Enabling Ultrasensitive Measurements on ElectroOptical Innovations

Antenna-Coupled Tunnel Junctions for Optical Interconnection

Tue, 10 Dec 2019 02:08:13 +0000

My silicon photonics work at IBM centred on the idea of integrating submicron silicon optical waveguides with metal plasmonic antennas and metal-insulator-metal (MIM) tunnel junctions, to build optical detectors and modulators in the 1.55 μm region.

POEMS: Programmable Optimizing Electromagnetic Simulator

Tue, 10 Dec 2019 02:08:39 +0000

There are a variety of EM simulation schemes in wide use, with different strengths and weaknesses. For free-space antennas at radio frequency, where dielectrics are simple and metals are excellent conductors, integral equation schemes such as the method of moments (MoM) win. At optical frequencies, particularly when metal is involved, partial differential equation methods are generally better. The two most common PDE schemes are finite element method (FEM) and finite difference, time domain (FDTD). The antenna-coupled tunnel junction work required simulations with very fine resolution (1 nm) in some places, to represent plasmons and metal surface discontinuities, and a very large simulation domain, at least 5 μm square by 20 μm long. This requires multiprocessor capability and subgridding, i.e. different places in the simulation domain having different cell sizes. Subgridding is a natural strength of FE, but presents a challenge in FDTD, which naturally likes uniform cubical grids. On the other hand, mesh generation can be very time consuming, and FEM doesn’t clusterize as well as FDTD and is much harder to get correct.

Laser Noise Cancellers

Tue, 10 Dec 2019 02:08:57 +0000

Laser noise is very often the primary limiting factor in making high-accuracy optical intensity measurements. There are ways of making your laser quieter, but they won’t get to the shot noise level. On the other hand, what we actually measure is the photocurrent, not the laser power, and that we can improve.

Laser Noise Cancellers are extremely powerful devices that allow us to make shot-noise limited measurements at baseband, even with very noisy lasers. With zero adjustments, they will reliably suppress the effects of laser residual intensity noise (RIN) by 55 or 60 dB from dc to several megahertz, and with a bit of (optical) tweaking, will do 70 dB or more at low frequency, which is where it’s most needed (see the picture above, which shows > 70 dB suppression of noise intermodulation). There’s a New Focus app note which surveys applications of noise cancellers.

The laser noise canceller has two operating modes, linear and log-ratio. The linear mode produces a replica of the photocurrent minus the noise. The log ratio mode also suppresses the intermodulation of the laser noise with the signal, allowing (for example) tunable diode laser spectroscopy to achieve 1-ppm sensitivities even when the laser power is varying by >30% over a scan line, as shown here.

ISICL: In Situ Coherent Lidar for Submicron Particle Detection

Tue, 10 Dec 2019 02:09:27 +0000

Particles in plasma etch chambers are a major source of yield loss in semiconductor manufacturing. Particles condensing from the plasma or spalling out of films on the chamber walls are levitated in the edges of the plasma sheath for long periods, and then (too often) drop on the wafer when the plasma excitation is turned off.

Process control and tool utilization can both be improved by knowing what’s happening inside the chamber while the process is going on—but how? The plasmas are usually too bright to look at, and there’s only one (poor quality) window in the typical chamber, so an optical particle detector would have to work in backscatter, with a huge background.

ISICL is capable of seeing and mapping individual particles of less than 0.2 μm diameter, as they float around in the plasma, a unique capability.

Heterodyne Confocal and Solid Immersion Microscopy

Tue, 10 Dec 2019 02:10:03 +0000

Optical phase is a wonderful thing—it can get you good topographical images of samples with no discernible amplitude contrast, for example, or allow you to disambiguate phase features from amplitude ones. My interest in phase-sensitive microscopes dates back to my graduate work—hence this paper. It gives design details and the theory of the heterodyne scanning laser microscope, including the point- and line-spread functions, plus a deconvolution method that can give resolution equivalent to an ordinary microscope working at λ0/2—ultraviolet resolution from a visible-light scope. Operating with a green Ar+2 laser (514.5 nm) and 0.9 NA, it attained a 10%-90% edge resolution of 90 nm.

This works because the interferometer makes it a confocal microscope, i.e. its amplitude point-spread function is the square of the illumination PSF. By the convolution theorem of Fourier transforms, that means that its bandwidth is twice as wide, i.e. ±2NA/λ. A bit of digital filtering turns the resulting nearly-triangular transfer function into something a bit more Gaussian-looking, which gives us a factor of 2 resolution improvement. Unlike the usual image processing ad-hockery, Fourier filtering makes absolutely no additional assumptions about the sample; the additional information comes from measuring both phase and amplitude, which is why you need an interferometer.

Footprints: A $10 Thermal Infrared Imager

Tue, 10 Dec 2019 02:10:30 +0000

A low-resolution thermal camera with competitive sensitivity (0.13 K NETD) at very low cost. Easily built from scratch—it requires no special parts, except a screen-printed sheet of pyroelectric PVDF polymer (as used in automatic porch lights) and a moulded polyethylene Fresnel lens. This camera achieves a cost reduction of 2 orders of magnitude ($10 vs $1000) over the next cheapest, which is a 256-pixel PZT array from Irisys, while maintaining very good sensitivity. These are from a project called Footprints.

The design is simple: screen-printed carbon ink on a free-standing film of PVDF polymer, with a multiplexer made out of ordinary display LEDs with a few interesting optical and electronic hacks, as shown in these photos.

SiPM Module

Wed, 24 Feb 2021 20:21:59 +0000

Specifications


3dB Bandwidth	From DC–200 kHz to DC–300 MHz
Rise Time	4ns (highest bandwidth configuration)
Gain Control Method	Gain settable by serial or analog voltage. Analog voltage control profile mimics behaviour of similar PMT modules.
Detector Type	Hammamatsu S13361/S13362 series or On Semi MicroFC series SiPm
Coupling	DC
Output Impedance	50 Ω
Dynamic Range	All configurations support analog and photon counting
Power Requirements	+5V 100mA, -5V 10mA
Signal Output	SMA
Applications	Flow cytometry, Microplate readers, TOF Lidar

In the last year or two we’ve been doing a lot of work aimed at replacing photomultiplier tubes (PMTs) in instruments, using avalanche photodiodes (APDs) and silicon photomultipliers (SiPMs). These devices are arrays of single-photon detectors, so they’re also known as multi-pixel photon counters (MPPCs). Our main application areas include biomedical instruments such as flow cytometers and microplate readers, which have to measure low light levels very precisely but don’t need the ultralow dark current of PMTs. (Follow-on articles will talk about our SiPM work in airborne lidar and SEM cathodoluminescence, as well as on improving the performance of actual PMTs.)

Featured Product: LA-22 Low Noise Lab Amplifier

Tue, 06 Jan 2026 13:08:08 +0000

The LA-22 Low-Noise Laboratory Amplifier, 800 Hz–22 MHz, 1.1 nV / √Hz

One problem that comes up again and again in doing measurements is that we need the apparatus to be quieter than the thing we’re measuring, ideally by at least a factor of two. Besides quiet, it should be wideband, have an accurately known gain that’s flat with frequency, have a clean step response, and generally do its job while keeping itself out of the way. There’s a wealth of detail in our app note AN-1 on photoreceiver testing.

"Super-Regenerative Receivers" by J. R. Whitehead

Mon, 29 Dec 2025 23:39:34 +0000

A quick plug for a little gem of a book that all fans of early radio should know about: “Super-Regenerative Receivers” by J. R. Whitehead (Cambridge University Press, 1950). It’s part of the Modern Radio Techniques series, where a bunch of the technical movers and shakers document the advances that were made during the war, e.g. centimeter radar. This one is about the theory and practice of superregenerative radios. I learned a lot from it and had a lot of fun.

Temperature Control 1: Simple Control Theory

Sun, 28 Dec 2025 21:48:25 +0000

Temperature Control

The need to control temperature is everywhere, but getting it right is more difficult than one might expect. A domestic furnace controlled by a simple thermostat keeps a house comfortable in winter, but the inside air temperature swings irregularly over a range of a few degrees. That’s fine for a house—you can have a New Year’s party, with a bunch of people dissipating a hundred watts each, doors to hot ovens and the cold outside opening and closing, no worries whatsoever. The heating system keeps it comfortable.

A High-Performance Time Domain Reflectometer

Wed, 05 Mar 2025 15:22:56 +0000

In a previous article, we described an ultralow-cost time-domain reflectometer (TDR) that is used as a radar dipstick for fuel gauges in heavy equipment. Its 150-ps edges were better than good enough, and its rock-bottom BOM cost ($1.30 @ 100 pcs) made it possible for the whole gauge to retail for under $40. That performance is far from the limit for low-cost samplers, as we’ll see.

Product Announcement: QL03 Photoreceiver

Wed, 19 Feb 2025 18:33:55 +0000

We’ve got a new photoreceiver available over at our sister site, Hobbs ElectroOptics. The QL03 Photoreceiver comes out of several proof-of-concept systems where we needed a high-sensitivity, low-noise optical receiver for low-light applications.

It features a massive 150 mm² photodiode with slight magnification from an immersion lens, making it especially effective for diffuse light measurements, spectroscopy, and fluorescence detection—plus, setup is a breeze since you’re aiming at a barn door.

A 150-Picosecond Time Domain Reflectometer for Under $2

Wed, 05 Feb 2025 12:08:10 +0000

One of the most enjoyable parts of electronics design is getting excellent performance with rock-bottom parts cost. The right circuit can produce exceptionally good speed, noise, and accuracy specs from very low-cost parts. A case in point was a project from December 2016: a time-domain reflectometer (TDR) for a liquid level sensing application in industry.

TDRs work by sending short pulses down a transmission line where they bounce off anything that disturbs their propagation. By measuring the time delay, you can tell how far down the line the disturbance is. It’s a bit like a one-dimensional radar, except that with TDR you can learn a lot more from the reflection than just its location. TDRs can find damaged optical fibres, waterlogged sections of coax cable, and many other things of that sort. This application used an air-dielectric coaxial probe built from two metal tubes sticking downwards into a tank, so that the first part of the probe had air as dielectric and the second part had liquid. The dielectric constant of a liquid is at least 2, whereas air’s is 1.0, so there’s a nice healthy impedance mismatch at the surface to reflect the pulse. This approach is very rugged and resistant to fouling (you can get all sorts of nameless crud in process water and diesel tanks, for instance).

Application Note: Photoreceiver Testing

Mon, 01 May 2023 16:05:03 +0000

We’ve published our first full-scale application note: AN-1: Photoreceiver Testing System . Based on our LP870 Nanosecond Light Source and LA22 Lab Amplifier, the system gives an easy and economical way to test photoreceivers as fast as 5 ns. In the time domain, it measures rise and fall times with excellent accuracy. In the frequency domain, it measures the noise floor (down to below 1 nV/√Hz), both dark and light, and gives a neat hack for measuring the transimpedance vs. frequency to very high accuracy.

Photomultipliers: There's a Lot to Love

Wed, 23 Jun 2021 18:35:14 +0000

Placeholder for a PMT article on photon counting, low-current analogue mode vs. MPPCs, and the high linearity version

What Photodetector Should I Use for Application 'X'?

Wed, 23 Jun 2021 18:27:50 +0000

We often get asked questions like, “How do I know what photodetector is best for (application X)?” For some values of X, it’s pretty simple: if you’ve got milliwatts of visible light, use a silicon PIN photodiode and an ordinary transimpedance amp (TIA) made from an op amp or (for faster things) a packaged 50-ohm RF amplifier. It’s usually easy to verify that you’re in the shot noise limit—if your photocurrent drops more than 50 mV across its load impedance, you’re there. (*)

Contact

Tue, 02 Feb 2021 22:43:22 +0000

Silicon Photomultiplier Module Design

Mon, 25 Jan 2021 16:30:28 +0000

Internal Developments

Signal to Noise Ratio and You, Part 2

Sun, 24 Jan 2021 13:05:47 +0000

In Part 1, we discussed ways to get better measurements by improving the signal to noise ratio (SNR), and saw that although it was often a win to measure more slowly and use lowpass filters, going too far actually makes things worse, because of the way noise concentrates at low frequency. Here we introduce a more sophisticated approach that generally works better: the lock-in amplifier.

We were considering a typical baseband signal, one that goes from near DC to some much higher frequency. Audio is a typical example, with a bandwidth usually quoted as 20 Hz to 20 kHz. To escape the low frequency noise, we need to move our signal up in frequency, out of baseband. In lock-in detection we make the signal periodic in time at some carrier frequency fc chosen to be several times higher than the required bandwidth. This is generally pretty easy to do, as we’ll see, and doing so ensures that none of the signal we care about remains near DC. Our noise rejection filter now needs to be a narrow bandpass centered at fc, so as to reject both low-and high-frequency noise. We’ll also need some means of measuring the amplitude and phase of the AC signal. That’s more complicated, of course, but with this setup we can narrow the bandwidth as much as we like and still get the full SNR improvement. A lock-in amplifier is a device for making such narrow-band AC measurements conveniently. It’s basically a radio that measures the phase and amplitude of its input, so that we recover a lowpass-filtered version of the baseband modulation signal that we care about, with no 1/f noise pollution to worry about. At this point we need to geek out a little bit and talk about modulation, which is what we mean by moving the signal away from baseband.

Signal to Noise Ratio and You, Part 1

Sun, 24 Jan 2021 11:16:17 +0000

In building an ultrasensitive instrument, we’re always fighting to improve our signal-to-noise ratio (SNR). The SNR is the ratio of signal power to noise power in the measurement bandwidth, and is limited by noise in the instrument itself and the noise of any background signals, such as the shot noise of the background light or the slight hiss of a microphone.

If the signal is weak, it will have proportionally more noise, so that the apparatus has to be designed to get rid of as much noise as possible. There are a number of ways to do this. The best is to get more signal or reduce the noise, for instance by increasing the laser power and using a laser noise canceller, but eventually we hit a practical limit. At that point, we’re left with several options, all of which boil down to filtering in one form or another.

Technology: Low Noise Thermoelectric Cooler (TEC) Controllers

Thu, 29 Oct 2020 14:06:35 +0000

Thermoelectric (Peltier) Coolers

A thermoelectric cooler is a solid-state device made from two alumina ceramic plates with an array of metallized pillars in between. The pillars are also ceramic–they’re made of alternating p-type and n-type bismuth telluride (Bi2Te) semiconductors, alloyed with antimony telluride (p-type) or bismuth selenide (n-type), and connected in series electrically. The Peltier effect makes them electric-powered solid state heat pumps. (Thermocouples work the other way round, via the Seebeck effect, but the physics is the same.)

Mirror of www.analog-innovations.com (Jim Thompson's site)

Tue, 14 Jul 2020 07:56:59 +0000

James Elbert (Jim) Thompson was a well-known chip designer who used to be a regular on sci.electronics.design. He last posted in July 2018. As he was very sick at the time, we presume that he has died, but no obituary has so far turned up. He was born on February 29th, 1940, and used to say that he was looking forward to his 21st birthday in 2024.

Jim had a consulting company, Analog Innovations LLC, and a website, http://www.analog-innovations.com. You can find it on web.archive.org, but those copies are incomplete. A complete archive (minus a bit of javascript) is here at

Low Frequency Noise In InGaAs Heterojunction FETs

Sun, 23 Feb 2020 09:01:14 +0000

InGaAs heterojunction FETs are magic parts—fast, strong, and extremely quiet. They’re also called pseudomorphic high electron-mobility transistors (pHEMTs), because they use a 2D quantum well to to force the conduction electrons to move in a plane without much scattering. My fave Avago ATF38143 pHEMT was discontinued, but luckily Mini-Circuits stepped into the breach with their very nice SAV-551+ and its siblings, which are similar enough that the ATF SPICE model can be hacked up to work with them. (RF companies like Mini-Circuits never seem to supply SPICE models for some reason.) In one post on the ‘purpose of precision’ thread on sci.electronics.design, I noted that the Avago ATF38143 model I had posted awhile back predicted way, way too much low frequency noise. The real pHEMTs tend to have a pretty accurately 1/f PSD with corner frequencies between 10 and 50 MHz and flatband noise of around 0.3 nV/√Hz, about 10 dB quieter than the best JFETs, as well as being 20 times faster.

How We Work

Thu, 30 Jan 2020 14:56:30 +0000

At EOI, we’ve been building advanced instruments for a long time. One reason for our success is our large inventory of working designs, and another is the way we go about doing it. This post walks through a typical sort of development plan for a challenging customer requirement, in the form of a hypothetical email proposal outline for a fibre-coupled noninvasive glucose sensor similar to the one we did in 2013.
(You can also read about a recent project that went a lot like this, except with a single prototype stage.)

Silicon Photomultiplier (SiPM, MPPC) System for Cathodoluminescence

Thu, 30 Jan 2020 11:57:07 +0000

In How We Work, we gave an overview of how we build instruments, from the initial feasibility calculation (or photon budget) to delivery of the first production units.

Each project is different, of course, but there are common themes. Here’s a description of these steps from our most recent one at this writing (late January 2020), which is a low-cost cathodoluminescence detection system for use in scanning electron microscopes (SEMs).

Photon Budget

Cathodoluminescence Principles

A SEM works by scanning a tightly-focused beam of high-energy electrons (1 keV - 30 keV) across a sample, and looking at the stuff that comes out. For ordinary imaging you usually look at backscattered and secondary electrons, but there are other modes. For instance, you can get a lot of information about the sample’s chemical composition by looking at the x-rays it emits. Most samples will also emit some amount of light, a process called cathodoluminescence .

How We Work: An Example

Mon, 27 Jan 2020 17:00:58 +0000

At EOI, we’ve been building advanced instruments very successfully for a long time. One reason for our success is our large inventory of working designs, and another is the way we go about doing it. This post walks through a typical sort of development plan for a challenging customer requirement. Here are the usual steps, in the form of a hypothetical email proposal outline for a fibre-coupled noninvasive glucose sensor similar to this one.
(You can also read about a recent project that went a lot like this, except with a single prototype stage.)

Silicon Photomultiplier (SiPM, MPPC) System for Cathodoluminescence

Mon, 27 Jan 2020 11:38:02 +0000

In How We Work, we gave an overview of how we build instruments, from the initial feasibility calculation (or photon budget) to delivery of the first production units.

Photon Budget

Cathodoluminescence Principles

Noninvasive Transcutaneous Blood Glucose: A War Story

Wed, 15 Jan 2020 16:55:20 +0000

Here at EOI we have three main kinds of project. One is our internal technology development projects. Some of these fail, mostly because they tend to be insanely hard, but the ones that pay off give us important new capabilities.

The second is research projects with customers, trying to push technological limits in fields such as biochip DNA sequencing, nanoantennas for infrared detection, ultrahigh resolution optical microscopy, hypersonic lidar, and (closer to home) infrared remote controls for consumer electronics. Those ones are a bit sporty, but succeed more often than not.

Good Books

Tue, 10 Dec 2019 21:20:58 +0000

Classic Books On Electro-Optics and Circuits In Softcopy

There’s also the 100 Good Books list from Building ElectroOptical Systems.

Books on Electro-Optics

MIL-HDBK-141: Optical Design

And, courtesy of the good folks at Any2DJVU:

Lab Equipment List

Tue, 10 Dec 2019 21:11:52 +0000

Here’s a partial list of EOI’s lab equipment. The list is heavily weighted towards electronic stuff, but we also have a very complete set of high precision optical and optomechanical parts: mounts, translation and rotation stages, lenses, prisms, polarization optics, gratings, filters, modulators, detectors, lasers, and fibres, for a start. This lets us try out new ideas quickly and build test setups to verify them.

If you’re also a fan of classical equipment, you can download manuals at Keysight (formerly Agilent, formerly HP) and Tektronix, liberatedmanuals.com, BAMA, Kurt’s Manuals, ElektroTanya.com, and K04BB. KE5FX’s GPIB Tools are pretty serviceable and also free. (NB: Keysight for some reason doesn’t allow deep links to their support pages—you have to go through the main page and select “support”.)

High-Value Ceramic Capacitors: They Stink, and You Can't Get Them Anyway

Thu, 26 Jul 2018 14:10:44 +0000

There are widespread shortages of electronics parts at the moment, especially passives. Quoted factory lead times are 40 weeks or thereabouts, and since the industry is capacity-limited, it isn’t clear that the situation is going to get better any time soon, so everybody’s starting to panic. Given all this churn I’ve been spending an unconscionable amount of time lately finding suitable replacements for out-of-stock parts.

High value ceramic caps are the worst–their capacitance drops by at least 60% and at worst 95% at rated voltage, so finding an adequate substitute involves a lot more than the package, value and voltage rating. Most of their data sheets are useless, which is frustrating. However, all is not lost: most makers have websites where you can look at the C(V) curves.

BEOS outtakes: Photographic Film

Tue, 20 Mar 2018 14:35:17 +0000

From the cutting room floor at Building Electro-Optical Systems, Third Edition:

Photographic Film
Okay, okay. Photographic film isn’t a detector of the sort we’ve been discussing. Film is so out of fashion, so inconvenient. It needs messy chemicals. Getting it to be highly sensitive requires all sorts of 1960s alchemy such as pre-flashing and hypersensitizing in a forming gas or hot hydrogen atmosphere. Why do we care about it at all, in these days of 4k x 4k CMOS imagers?

Temperature Measurement is Hard

Fri, 09 Mar 2018 09:52:10 +0000

Measuring temperature is surprisingly subtle. There are lots of sensors out there; Digikey sells thermistor sensors interchangeable to +- 0.1 C from several vendors for about $3 in onesies. IC sensors tout good accuracy and linearity, and come in both analogue and digital versions for way under a buck. So what’s the issue?

The issue is: temperature sensors measure the temperature of the sensor, whereas what we want is the temperature of something else: air, fluid, or some solid object we’re trying to control. So the problem is to get the sensor temperature to track the temperature we actually care about. IC sensors are especially bad, because they have stout leads made of copper (400 W/m/K thermal conductivity) and small packages made of plastic (0.1 W/m/K). Thus they basically measure the temperature of their leads, and are horrible at measuring air temperature, for instance.

Footprints Project

Sat, 24 Feb 2018 22:41:26 +0000

Pizzafil

Sensor2small

Sidestacksmall

Sensorasmall

Decap Photo of Terabeam APD Photoreceiver

Sat, 24 Feb 2018 20:53:26 +0000

Decap picture of a Terabeam CD3109 APD/TIA module, taken with a lens glued to a cell
phone camera

Thermal Runaway Found Useful

Sat, 24 Feb 2018 20:51:39 +0000

This odd circuit is an on-chip temperature balancer that uses thermal runaway to force N transistor arrays to all run at the same temperature. BJT dissipation goes up at low temperature, with very high gain. Here’s its step response.

Sine Wave Generation with TANH Wave Shaper

Sat, 24 Feb 2018 20:46:04 +0000

Sine wave generation is a perennial problem.

Direct-digital synthesis (DDS) uses a bunch of counters, lookup tables, and DACs,
but that’s a relatively heavyweight solution that doesn’t fit all problems.
BJT differential pairs naturally have a hyperbolic tangent (tanh) characteristic, which can be used to round off a triangle wave into a very passable sine. I’m not old enough to have invented this technique, but here are a couple of illustrations of how it works: TANH Sine Wave Shaper (PDF) and TANH Sine Wave Shaper (Mathcad).

Care and Feeding of Tantalum Capacitors

Sat, 24 Feb 2018 20:40:06 +0000

Solid tantalum capacitors have a lot of advantages: very low inductance in surface mount packages, ESR low but not so low that your LDO regulators start oscillating; and good capacitance per unit volume. Unfortunately they’re also prone to burn up when mistreated, which makes many engineers wary of them. This war story, entitled What a Cap-astrophe! talks about how to treat them properly, and how a bit of TLC after soldering can restore their full performance.

High Dynamic Range FET Bridge Mixers

Sat, 24 Feb 2018 20:34:12 +0000

For RF folks, one of the perennial quests is for better frequency mixers: lower distortion,
lower power, better spurious performance. FETs can help. Nowadays CMOS muxes are the devices of choice for HF mixers, but to get the best performance, you still have to know how they work. Ed Oxner was a long-time Siliconix apps guy, and his paper on High dynamic range FET RF mixers is still right up there with the best.
(From a Siliconix databook, 1985.) The FET mux approach is often credited to Dan Tayloe, but since they work just the same, the “Tayloe mixer” should really be called the “Oxner mixer”.

Noise Peaks From Linear Voltage Regulators

Sat, 24 Feb 2018 15:10:29 +0000

Erroll Dietz is a remarkable fellow. He started out at National Semiconductor as Bob Pease’s
technician, and rose to become Chief Technology Officer.

Feedback amplifiers generally have an output impedance that rises linearly with frequency—in other words, it’s
inductive. As Dietz’s short paper from Electronic Design shows, this effective inductance can
resonate with the output bypass capacitor to cause really nasty noise peaks in the 1-100 kHz region. If you have an inexplicable noise peak in that range, a small resistor (a few tenths of an ohm to an ohm or two) in series with the regulator output can be just the ticket. You can also put it in series with the cap, but if you do that, make sure it’s a pulse-withstanding type, or it’s liable to blow up by an output short-circuit, or even the inrush transient, e.g. if somebody runs your gizmo off batteries.

Random resources from my Usenet posts on sci.electronics.design

Sat, 24 Feb 2018 15:03:20 +0000

Sometimes it’s useful to add supporting documents, schematics, scope photos, simulations or other things to Usenet posts. By popular request I’ve added links to some of these, in no particular order.

A trick for turning the usual proportional/integral (PI) loop filter of a phaselocked loop (PLL) into a sweep generator for lock acquisition.

A big slide deck with ideas on Getting Photodetection Right (from a talk given at BBN in Cambridge MA)

How To Read SED: Archive Sites and Newsfeeds

Sat, 24 Feb 2018 14:34:57 +0000

One of the nice things about sci.electronics.design is that it’s widely redistributed by archive sites, some of which you can also use for posting, which is good since Google Groups no longer links to Usenet.

Some examples:
electronics-related

Narkive

Electron Depot

It’s really better to use a proper newsreader such as Thunderbird or Forte Agent. You can get a free Usenet account from Eternal September, and cheap ones from Supernews or astraweb.

SED has been around for a long time. Archives going back to 1993 are available from Archive.org, and have a lot, a lot of good stuff. (Plus the usual allotment of Usenet flame wars and so on.)

Expert Case: Waymo LLC v. Uber Technologies, Inc., et al.

Fri, 16 Feb 2018 16:50:46 +0000

This was a patent and trade secret case concerning lidar (laser radar) technology for self-driving cars and trucks. It was the biggest case I’ve worked on, with potential damages over $2 billion, and also one of the most fun. I was the defendant’s expert on the patent side, and we beat Google–they dropped all their patent assertions. (This was made a lot easier by the fact that Uber wasn’t infringing, of course.)

New Web Site

Sun, 12 Nov 2017 19:34:10 +0000

Thanks to the efforts of our newest member, Simon Hobbs, we have a new web site with a new look and lots of new content, with more to come. We hope you enjoy it!

EXFO Inc. et al. v Viavi Solutions, Inc.

Sun, 12 Nov 2017 14:49:52 +0000

In this one I was engaged as a testifying expert for the plaintiff in an action for patent infringement in optical time-domain reflectometers (OTDRs) used for testing fibre-optic networks. As so often happens, the defendant petitioned the Patent Office for an inter partes review of the patents-in-suit, which I also assisted with. The most unusual feature of this one was the really ferocious protective order covering the defendants’ source code–it had to be printed on blue paper, one hard copy only, no soft copy, and kept locked in a steel cabinet at all times when not actively in use.

Neutral Referee in IP dispute between former joint development partners

Sun, 12 Nov 2017 14:38:33 +0000

In the spring of 2017, I was approached by lawyers from two technology companies working in civil avionics (instruments for airplanes). I can’t say who they were due to NDA restrictions, but the job was an unusual and interesting one. The two companies had been joint development partners, but the relationship had soured and trust had now broken down completely. Both were concerned that the other was misusing intellectual property disclosed during the joint venture, and they asked me to do do an audit to see whether this was in fact true. The situation was made more complicated because one company was several hundred times as large as the other, and of course there was no court-ordered discovery and no one was under oath.

Lab Tour

Thu, 02 Nov 2017 11:11:46 +0000

Come on into the EOI lab and we’ll show you around!

We'll start with my office door and pan around to the right.

Since I do a lot of stuff on B-size vellum, the antique drafting table is appropriate. The print is Botticelli's Madonna del Libro.

Here I'm in the middle of going over the schematics for an ultrastable cavity-locked laser (Allen variance < 1E-10 @ 100,000 seconds)

Voxpath RS, LLC v. Desay A&V Science and Technology Co. Ltd, et al.

Thu, 07 Sep 2017 16:50:20 +0000

Testifying defense expert representing Samsung in an action for patent infringement concerning optical storage, holographic optical elements, tracking servos, and signal integrity.

Industrial Technology Research Institute v. LG Corporation, et al.

Thu, 07 Sep 2017 16:50:01 +0000

This was another fun one with a lot of reverse engineering. This time round I was working with the plaintiff, Industrial Technology Research Institute, which is a research lab owned by the Taiwanese government. It was an action for patent infringement in the focusing and tracking servos of optical disc drives, as well as in the arrangement of the laser sources. The patent claims at issue concerned the way the magnetic “voice coil” actuators simultaneously adjusted focus, tracking, and tilt, so I needed to take several of the accused products apart and run the head servos by themselves in my lab. I also had to cut apart some of the coils to show how they were wired, and decap the lasers to show that there were two chips side-by-side in the CD/DVD source and one in the BluRay source.

ThinkOptics, Inc. v. Nintendo of America, et al.

Thu, 07 Sep 2017 16:49:42 +0000

Testifying expert representing ThinkOptics in an action for patent infringement concerning video games, specifically the human interface of the Nintendo Wii.
February 15, 2015: Settled after an inter partes re-examination.

Two strange cases: Yufa v. Lockheed Martin and Yufa v. Hach Ultra-Analytics

Thu, 07 Sep 2017 16:49:23 +0000

Particle counter showing gold mirror

This was quite an unusual situation. Dr. Aleksandr L. Yufa had several patents relating to optical particle counting, and tried to get various companies to license them. I don’t know if any actually signed up, but obviously some didn’t, because he sued several manufacturers and users of these technologies for infringement. The unusual part was that Dr. Yufa was acting pro se, that is, he was acting as his own lawyer.

Morgan Solar v. Banyan Energy

Thu, 07 Sep 2017 16:49:07 +0000

An interesting though brief patent interference case concerning flat-panel solar concentrators. The plaintiff (Morgan) had filed a continuation patent application, which is a means of getting additional claims out of a previously-filed specification. The new patent gets the same priority date as the old one, so you don’t have to worry about later art (such as that of the competitor whom you want to pay you royalties), but you don’t get the usual 20-year patent lifetime. Morgan then came after Banyan.

Texas Advanced Optoelectronic Solutions, Inc. v. Intersil, Inc.

Thu, 07 Sep 2017 16:48:45 +0000

It isn’t easy defending an IP lawsuit in the Eastern District of Texas.

This was a long-running case alleging patent infringement and trade secret misappropriation. Chipmaking company Intersil Inc. wanted to get into the market for ambient light sensors (ALS). An ALS is a tiny chip that goes into phones and other battery-powered devices, which lets the processor know how brightly lit the device’s surroundings are. That lets it adjust display brightness automatically to compensate, which saves battery power in dim surroundings and keeps the display from being too bright or too dim.

InGaAs Photodiode Characterization Drift and 1/f Noise at 70-90 °C

Thu, 07 Sep 2017 16:47:58 +0000

Drift and 1/f Noise at 70-90 °C
Sometimes you have to find out things that aren’t in the datasheet, and even the manufacturer may not know.

Thermoacoustic Refrigeration

Thu, 07 Sep 2017 16:47:30 +0000

Thermoacoustic fridges are magic: you heat one end, and the other end gets cold. (Of course you have to sink all that heat from the middle.) They can easily be made long and skinny, and so are a natural for use down drillholes. They’re also made entirely of metal, and have no moving parts, so they will survive bouncing around in the back of a truck.

This was a design study for a general purpose fridge for 2-inch cased holes (38 mm maximum OD) that would solve many of the temperature problems of downhole operation for a wide variety of sensors.

Transdermal glucose detectors based on optical coherence tomography

Thu, 07 Sep 2017 16:46:56 +0000

This was a photon budget for an OCT system—interesting primarily for the effect of path delay in turning FM noise in the superluminescent diode (SLD) into AM noise in the measurement.

Mixed-reality head-mounted projection displays

Thu, 07 Sep 2017 16:46:01 +0000

I chaired a series of formal design reviews for a start-up company making immersive displays with resolution better than the human eye.

All-Optical Downlink for Antisubmarine Warfare (ASW) sonobuoys

Thu, 07 Sep 2017 16:45:42 +0000

Another Della project for the Navy: I did a photon budget that showed that this could be done optically within the power and weight constraints, and would work in bright sun as well as at night. (Optical communications are much harder to intercept or to jam than radio.)

Integrating vs. TIA front ends for compressive-scan cameras

Thu, 07 Sep 2017 16:45:17 +0000

A shootout between the two major classes of transimpedance amplifier (TIA) designs for one difficult corner of the design space.

13.5 nm EUV Lithography: Tin Droplet Detection System

Thu, 07 Sep 2017 16:44:13 +0000

When you’re hitting a droplet with enough pulsed CO2 light to generate X-rays efficiently, you have to know exactly when it’s going to cross the focus.

RF Design for Ion Trap Mass Spectrometer RGA

Thu, 07 Sep 2017 16:43:50 +0000

Producing an integrated model of circuit conditions and ion motion, allowing optimization of circuit and excitation parameters, plus sanity checking

Touch Panel Displays: Low-Cost Optical Front End

Thu, 07 Sep 2017 16:42:01 +0000

In cooperation with Flatfrog Laboratories AB, Lund, Sweden. This one was interesting mostly due to the requirement for high and stable performance at an absolute rock-bottom cost.

Plasmonic Nano-Antennas for Thermal Infrared Pixels

Thu, 07 Sep 2017 16:41:41 +0000

This was a seedling design study for a DARPA program that never got funded. It leveraged POEMS and my antenna-coupled tunnel junction devices, adding a couple of novel wrinkles: metal-insulator-metal varactors and parametric readout using a 10 GHz pump frequency. Hopefully there will be a chance to revisit this, because it was potentially a pretty sweet solution.

Long-range IR transceiver

Thu, 07 Sep 2017 16:41:18 +0000

For a large Far Eastern consumer electronics manufacturer to use in virtual reality games. A greatly improved transimpedance amplifier got them a factor of 10 in range (30 m vs. 3 m) for about the same amount of power.

Aircraft Carrier Flight Deck Optical Communications Link

Thu, 07 Sep 2017 16:40:41 +0000

Photon Budget and Optical Data Receiver
This one was a somewhat similar application for the Navy.

Ad Hoc Optical Battlefield Network: Optical Data Receiver

Thu, 07 Sep 2017 16:40:00 +0000

This was a collaboration with Chris Wieland of Della Enterprises on an Army Research contract.

Downhole Interferometry: Cavity-Stabilized 1550-nm Laser

Thu, 07 Sep 2017 16:10:00 +0000

This was in collaboration with a start-up in New Mexico called Symphony Acoustics. Downhole measurements are notoriously difficult, and this one was no exception: building a laser that could achieve an Allan variance of 10-10 at 10,000 seconds, and do it 5000 feet down a 2-inch cased drillhole. Due to the casing thickness, the maximum outer diameter of the instrument package was 38 mm, including its own casing and two concentric zones of thermal control.

Nuclear Nonproliferation: 100-MHz Noise Cancelling Front End

Thu, 07 Sep 2017 16:09:38 +0000

This was in cooperation with Mesa Photonics of Santa Fe NM. It’s part of a DOE program, an advanced deployable solar occultation spectrometer for detecting volatile plumes from clandestine uranium enrichment.

Their scheme uses a really cool technique: solar heterodyne detection. It’s a good illustration of the importance of a photon budget.

32-Channel IR Detector for Compressive Scanning Camera

Thu, 07 Sep 2017 16:09:22 +0000

A follow-on to the single channel version. This one had to work at very much lower power, which required a new amplifier topology based on local feedback around a very low noise JFET. This was a very fruitful development, which has been used in a number of follow-on designs.

Compressive-Scan Camera: 1-Channel IR Detector Analog Front End

Thu, 07 Sep 2017 16:08:31 +0000

In cooperation with InView Technology. Compressive scanning is a scheme for doing image sensing with a single-element detector, without suffering the N2 speed penalty of raster scanning. It’s a sort of combination of scanning and image compression—you use a digital micromirror device (DMD) to multiply the image by a series of 1-bit digital basis functions, measure the resulting photocurrent, and then invert the transform to produce a compressed image. That’s not too useful in the visible, where image sensors are cheap commodity items, but in the UV and especially the shortwave IR (SWIR), image arrays are extremely expensive, so there’s a need for compressive scan cameras.

Current Amplifier for Nanopore Biochips for DNA Sequencing

Thu, 07 Sep 2017 16:07:03 +0000

Discussion on the topic here.

This one came from a a major industrial research laboratory: near shot noise limited detection of 1 nA currents in 100 MHz bandwidth.
This was one that I wasn’t at all sure would work: it’s pretty sporty trying to detect a few dozen electrons at 100 MHz in a built-up circuit. (A 100-MHz lowpass has a time-domain response about 5 ns wide, and 1 nA in 5 ns is 31 electrons.) Obviously to get the highest available signal voltage, the input-node capacitance has to be absolutely the minimum possible: less than 1 pF.

Instrumentation: Wideband Laser Noise Canceller

Thu, 07 Sep 2017 16:06:39 +0000

60 dB of laser RIN cancellation out to > 10 MHz, about 100 times faster than current commercial devices

Spectroscopic-Detection Biochips Based on Photonic Waveguides

Thu, 07 Sep 2017 16:05:15 +0000

Using POEMS to design waveguides, coupling structures, and optical/chemical interaction regions; consulting on microfabrication issues

Bootstrap Charge Sensitive Front End

Thu, 07 Sep 2017 16:04:46 +0000

This is for for a scanning surface potential measurement tool, used in contamination detection in semiconductors: 40 attocoulomb sensitivity in a 4 MHz bandwidth

SWIR Grating Spectrometer Proof of Concept

Thu, 07 Sep 2017 16:03:52 +0000

This was a prototype of a transcutaneous (through-the-skin) sensor for blood glucose and blood alcohol.

Optical and optomechanical design, detection and control electronics and software, prototype construction: first spectra were taken 5/16/2013, and technology transfer to a contract engineering firm was essentially completed 6/14/2013.

Most notable was the schedule requirement: from a standing start, in less than 6 weeks’ work, I did a complete photon budget, designed and built all of the optics and electronics, wrote all the software, integrated and shipped the system. It worked great.

Blood Detector for Egg Grading

Thu, 07 Sep 2017 16:03:12 +0000

A bit of a departure from our usual fare: a low cost, high speed sensor for detecting blood spots in eggs using spectral differencing. I’m going to be doing the firmware as well as the optics and electronics, and this will be the first actual client work for our newly qualified PCB designer, Magdalen.

Competing devices use xenon flashtubes and very expensive photodiodes, but still need a lot of calibration and tweaking. That makes it a good candidate for our signature technique: A really careful photon budget followed by a design that actually reaches the theoretical optimum performance.

Plate Reader for Water Quality Assay

Thu, 07 Sep 2017 15:59:53 +0000

This is a research project with a small division of a very large manufacturer. It’s a complete optical/electronic design to measure optical absorbance in a rapidly moving assay plate.

Shot-Noise Limited Sub-Nanoamp Photoreceiver for Spectroscopy

Thu, 07 Sep 2017 12:41:18 +0000

This is a smaller job for a sensor manufacturer, interesting mostly for the size, weight, and power (SWaP) requirements. It has to be shot noise limited above 500 pA with a 1600 pF photodiode. (This is possible only because the bandwidth is relatively small.)

Doubling the Resolution of Solid Immersion Microscopes: Update

Thu, 07 Sep 2017 12:38:44 +0000

This is a very exciting development, in cooperation with a semiconductor equipment manufacturer. Back in 1989, my colleagues and I started working on a contact-lens microscope for looking into the interior of silicon chips through the back surface. In 1992 I took a picture (shown above) at a numerical aperture of 2.5, with resolution equivalent to NA 3.5 due to a confocal design.

Cascode Enhancement pHEMT Photodiode Preamp

Thu, 07 Sep 2017 12:30:22 +0000

This is pretty small, because it has to be–those are microwave transistors, and will oscillate at the slightest provocation. The axial resistors and TO-92 parts are all for biasing—the actual amplifier is the part between the output coupling cap (the small orange thing in the middle) and the photodiode, which is the white square with the black middle at the right.

The 0.1-inch pitch holes round the outside and 25-mil pad pitch set the scale.

Transistor Tester for laser noise canceller

Thu, 07 Sep 2017 12:27:50 +0000

As discussed in medium-gory detail in this paper, laser noise cancellers can let you do shot-noise limited measurements at baseband with lasers that are as much as 70 dB noisier than that.

They’re limited by two main effects: beta nonlinearity (1/hFE-1/hfe) and log nonconformance (d ln(IC)/dVBE - kT/e).

This tester measures both of these quantities directly. It’s a one-off, of course, so it’s done with discrete logic and instrumentation amp parts. It has certain points of interest, for instance the use of a unity gain instrumentation amplifier as a precision +1/+2 gain amplifier. One loose end: U1 is a LT1043 switched-capacitor building block—a glorified MUX that has very low charge injection and very good common-mode rejection.

Inter Partes Review for Fluorescent Bar Signs

Fri, 02 Oct 2015 15:00:23 +0000

Sometimes the expert has to tell the client that their case probably won’t hold up. This case was an excellent example: University of Cincinnati v. Crayola, Inc.

As happens so often, the defendant had petitioned for a reexamination of the asserted patent, and I was asked by the plaintiff to help out. The patent-in-suit was a division of an older case, so the specification had a lot of good inventive stuff in it, but the actual claims of this patent concerned ultraviolet-activated fluorescent displays (the black-light ones you see in bars and restaurants that you write on with a fluorescent marker). An interesting idea, for sure, but one that has been in wide use since the 1960s at least.

Industrial Technology Research Institute v. LG Electronics et al.

Fri, 12 Jun 2015 10:26:16 +0000

January 2013 - June 2015.

Here I was a testifying expert working with the plaintiff in a case involving the fancy voice-coil electromagnetic actuators that control tracking and focus in optical disc drives (CD, DVD, BluRay). I did a lot of reverse engineering, including driving the actuators and taking video showing their operation, unwinding the coils to show their winding pattern and connections, that sort of thing. The case was stayed for quite awhile and then settled, so full reports and testimony weren’t required.

Texas Advanced Optoelectronic Solutions (TAOS) v. Intersil Inc.

Fri, 03 Apr 2015 14:36:00 +0000

November 2009 to March 2015

This was a very large ($100M) action for alleged patent infringement and trade secret misappropriation concerning ambient light sensor (ALS) chips. (These allow your phone to adjust the screen brightness to optimize readability and battery life.) I was testifying expert for the defendant on the trade secret side of the case, working with the late Dr. A. Bruce Buckman on the patent side. After an unsuccessful negotiation for Intersil to acquire TAOS, Intersil developed its own line of ALS chips. TAOS sued, alleging that these were based on TAOS intellectual property.

At Trial in TAOS v Intersil

Thu, 05 Feb 2015 19:50:30 +0000

I’m testifying in my first trial, as an expert witness on the trade secret side of a complicated lawsuit alleging patent infringement, trade secret misappropriation, among other things. As a technical expert, I have to sit through the whole three-week trial to make sure I don’t miss any relevant testimony, even though I’ll probably be on the stand for no more than three or four hours. It’s actually pretty interesting.

Coherent Laser Radar for Vehicles and Navigation

Wed, 04 Feb 2015 15:55:31 +0000

Coherent laser radar (often miscalled lidar) is an ultrasensitive method for measurement of distance and radial velocity. It uses low power CW lasers and has excellent resistance to ambient light and interference from other laser radars. I’m doing a design for a unit suitable for vehicles and small ships (e.g. tugboats).

Doubling the Resolution of Solid Immersion Microscopes

Sat, 20 Dec 2014 15:57:41 +0000

This is a very exciting development, in cooperation with a semiconductor equipment manufacturer, I’m building a visible-light scanning microscope with six times higher lateral resolution than is possible with a normal microscope. It’s based on my Ph.D. thesis work and some things I did at IBM long ago.

Optical Devices LLC v. Lenovo et al.

Tue, 30 Sep 2014 09:50:40 +0000

January-September 2014

Sometimes you just get blindsided. Back in the mid-1960s, shortly after the laser was invented, a couple of smart guys named Norman Wild and Paul Leavy were working for a defense contractor in New Hampshire called Sanders Associates (now part of BAE Systems). They came up with a clever idea for spotting snipers on a battlefield, based on a laser and a special property of the eye. Most of us have seen the way a cat’s eyes seem to glow in the dark: their retinas are retroreflectors much like a bicycle reflector or a safety vest, that send light back preferentially the way it came. Human retinas do that too, though not quite as obviously. (Before smart digital cameras, photos taken with direct flash tended to show people’s eyes glowing bright red for this reason.)

Summary Judgment Granted In Yufa v. Lockheed Martin

Mon, 23 Dec 2013 18:17:00 +0000

Based in large part on my expert reports and reverse engineering of accused products, our Motion for Summary Judgment was granted. In the order, Judge Beverly O’Connell stated that the defendant “…has shown that Plaintiff has failed to produce evidence to support his claims for patent infringement.”

This is especially satisfying to me, since although I had been retained only in September, the case had been dragging on for over six years, and a previous motion for summary judgment had been denied. (The only drawback is that I had been looking forward to testifying in January.)

Three New Projects

Mon, 23 Dec 2013 18:16:10 +0000

Three interesting new engineering projects have come in: a microplate reader subsystem for water quality assays; a sensor front end with very stringent size, weight, and power (SWaP) constraints; and a scanning microscopy development system.

(Picture credit: https://en.wikipedia.org/wiki/File:Microplate_reader.jpg)

New expert case: Morgan Solar v Banyan Energy

Fri, 20 Dec 2013 18:14:55 +0000

I’ve been retained by Banyan in a patent interference case regarding concentrator-type solar collectors.

The mountain hath been in labour....TAOS v Intersil is going again

Tue, 28 May 2013 18:08:46 +0000

After almost exactly three years waiting for a claim construction ruling, this case has gotten started again. I’m working on the trade secret side of a complicated suit arising out of a contemplated acquisition that wasn’t completed.

Another New New Expert Case

Fri, 22 Feb 2013 18:05:28 +0000

I’ve been retained in NTRI v LG Electronics et al., another optical disc patent infringement case.

DCG Systems, Inc. v. Checkpoint Technologies, LLC

Thu, 10 Jan 2013 16:50:44 +0000

Testifying defense expert in an action for patent infringement concerning solid-immersion microscopy and laser voltage measurement in semiconductors.
Recent items:

April 2012: Wrote claim construction declaration;
May 1, 2012: Gave deposition in support of claim construction declaration;
May 23, 2012: Assisted in tutorial
December 2012: Case settled

Two New Expert Cases, One Settles

Mon, 10 Dec 2012 18:03:36 +0000

A case I’ve been working on since March 2012, DCG Systems v Checkpoint Technologies, has settled, and I’ve been retained in two others, ThinkOptics v Nintendo et al. (helping ThinkOptics with an inter partes reexamination), and Voxpath RS v Desay et al. (defending Samsung in an optical disc case).

Two New Front Ends for Scanning Surface Voltage Tool

Mon, 19 Nov 2012 17:59:25 +0000

I’m designing two brand new front ends for a scanning surface voltage tool for semiconductor manufacturing. Normally there are two ways you can measure surface potential—the vibrating Kelvin probe, which gets you the actual voltage but is very slow, or the fast-scan method, which is fast but gets you only the 1-D derivative of the potential.

Working with a leading semiconductor tool vendor, I’ve come up with both an improved transimpedance front end and (more interestingly) a new class of front end amplifiers that should be able to get the actual voltage like the Kelvin probe while going fast like the scanning method, while providing at least 15 dB SNR improvement over either one.

Photonic Biochips

Wed, 19 Sep 2012 17:36:13 +0000

(We can’t show ours due to NDA requirements– this is a cool one from Brown University that uses plasmonics.)

We’ve just started a collaboration with a prominent biotech company in California on spectroscopic-detection biochips using photonic waveguides. Our part of the effort is to explore the design space and come up with new topologies to maximize signal-to-noise ratio and measurement stability. This is an excellent application for POEMS as well as being an exciting new area for us.

Finisar Corp. v. Oplink Communications, Inc.

Thu, 05 Jan 2012 16:51:40 +0000

Testifying defense expert in an action for patent infringement in GBIC optical transceivers. Advised and performed some reverse engineering.
(settled quickly in 2011)

NTech Industries, Inc. v. Holland Scientific, Inc.

Wed, 07 Sep 2011 16:52:01 +0000

March-June, 2009.

Holland ACS470

This was my first expert case, beginning shortly after I left IBM. It was a patent infringement case concerning real-time spectroscopic optical sensors for precision agriculture, i.e. finding the condition of each plant or small region of a field, and applying just the right amount of fertilizer or pesticide. Precision agriculture is a win all round; it improves crop yields, prevents the spread of pests, while reducing the cost of chemicals and minimizing the runoff of those chemicals into waterways and ground water.

New Premises

Fri, 01 Jul 2011 16:19:58 +0000

160 North State Road, Suite 203, Briarcliff Manor, NY

I’m happy to announce that as of July 1, 2011, EOI is now in a larger and more convenient space, still in Briarcliff. As you can see in this photo tour, it provides a much larger lab area as well as a library/storage area and a second office for visitors and perhaps a colleague.

EOI is very well equipped for electronic, photonic, and electro-optical design and prototyping, from the infrared to the ultraviolet and from DC to 40 GHz. As you can see from the equipment list, I have a very large and varied collection of optical, mechanical, and electronics parts of all sorts, that allows me to try new ideas out very quickly.

PH200 Nanowatt Photoreceiver

Tue, 05 Apr 2011 16:09:09 +0000

Besides info on do-it-yourself photoreceivers, I am introducing a new line of electro-optical products in cooperation with Highland Technology, a cutting-edge instruments company in San Francisco. The first product is a shot noise limited free space photoreceiver with quantum-limited sensitivity from 60 nW to 100 μW and an honest 1 MHz bandwidth (3 MHz on the 100 μW range). For photocurrents below a microamp, it’s significantly better than even the bootstrapped cascode, and it comes in a nice module that fits your setup easily and has normal normal 1/4-20 and M6 threaded mounting holes.

Building Electro-Optical Systems: Making it all Work

Mon, 01 Jan 0001 00:00:00 +0000

This book is an attempt to provide a systematic and accessible presentation of the practical lore of electro-optical instrument design and construction: in other words, it’s the book I needed as a graduate student, but couldn’t find.

It’s intended in the first instance for use by oppressed graduate students in physics and electrical engineering, who have to get their apparatus working long enough to take some data before they can graduate. When they do, they’ll find that real-world design work has much the same harassed and overextended flavor, so in the second instance, it’s intended as a self-teaching guide and professional reference for working electro-optical designers.

Capability

Mon, 01 Jan 0001 00:00:00 +0000

Equipment — a partial list of EOI’s lab equipment
Lab Tour — photos from around the EOI lab

Consulting

Mon, 01 Jan 0001 00:00:00 +0000

Consulting Services

I got started in consulting during my 20 years as a Research Staff Member at IBM T. J. Watson Research Center. I began in the Manufacturing Research department, building special instruments for unique manufacturing problems for which commercial solutions did not exist, such as scanned-probe and solid-immersion microscopy, and in-chamber particle detection. I also did a fair amount of firefighting, retrofitting semiconductor lithography equipment for new capabilities, and helping fix problems that were causing immediate revenue loss in manufacturing. Later I developed new classes of computer input device, advanced scanning technology, and a new class of photonic detector and switch for optical interconnection, based on metal-insulator-metal tunnel junctions.

Expert Witness Work

Mon, 01 Jan 0001 00:00:00 +0000

With more than 30 years’ experience designing electronic, optical, and mixed-technology systems, and 43 US patents issued or pending, I have amassed a lot of expertise in a number of fields, including optics, optoelectronics, electro-optics, photonics (especially silicon photonics), analog electronics, optomechanics, optical and atomic force microscopy, semiconductor processing, signal processing, simulation, electromagnetics, due diligence, and the drafting and technical interpretation of patents.

Expert witness work is one natural application, and I’ve been testifying expert in 35 matters to date, including inter partes reviews and cases in district court and before the International Trade Commission. I’m expert in optics, photonics, microscopy, and analog electronics, as well as some areas of semiconductor processing, metrology, and testing. I’ve also written about 150,000 lines of C++ code, mostly for electromagnetic simulation, instrument control, and embedded applications, so I do a lot of reverse engineering and source code review as well.

Patents

Mon, 01 Jan 0001 00:00:00 +0000

Here’s a list of links to PDFs of the patents on this site. A few of these cases were also filed overseas. We’ve also recently filed a provisional application on the thermal Faraday shield.

I also do a fair amount of expert witness work in patent and trade secret cases. I’m always interested in new work, so send me an email and let’s talk about your application.

Solar Photovoltaics

Quantum Computing

US07889992: HYBRID SUPERCONDUCTOR OPTICAL QUANTUM REPEATER

Optical Interconnection

Footprints: a Network of Distributed Low-Cost Infrared Imagers

Ultrasensitive Measurements

Instruments for Manufacturing and Process Control

Advanced Scanning Technology

Solid-Immersion Microscopy (NA=2.8 to 3.2)

Scanned-Probe Microscopy

US05298975: COMBINED SCANNING FORCE MICROSCOPE AND OPTICAL METROLOGY TOOL

Recent Work

Mon, 01 Jan 0001 00:00:00 +0000

EOI works with customers of all sizes, from garage startups and university research groups to the largest companies in the electronics, defense, biomedical, and semiconductor equipment industries. We do research, technology selection, product design, IP licensing, and expert witness work in both patent and trade secret cases. We’re always ready to help with debugging and firefighting as well—we learned some of this stuff the hard way too.