Teltec Pacific is a technical Sales and Service organisation serving the Semiconductor, Photonics and Optoelectronics Industries in Asia Pacific countries.


Electro-Optical Systems Inc has been operating as an independent riginal equipment manufacturer of photodetector/photodiode components, detector, bassemblies and custom instrumentation covering the complete UV/vis - 40 micron spectral region since 1983,.

Our broad product line finds application in OEM instrumentation and test equipment, optical testing, quality control, laser detection and characterization, thermometry, spectrometry, process control, enviromental sensing, gas analysis, fiber-optic sensing, device characterization and a variety of other optoelectronic uses.

Products are in use world-wide with customers that include test equipment manufacturers, instrument manufacturers, colleges and universities, government agencies, industry research and development labs, aerospace and defense contractors, and process control systems manufacturers. EOS’s philosophy is to provide standard and custom engineered "turnkey" products which are user-friendly, represent state-of-the-art performance, and more importantly are the optimum solutions for customers' projects.

Product Index:

          Detector Components + Pre-Amplifier Electronics

          Power Supplies, TE-Controllers, Pre-Amplifiers, Data Acquisition Systems, etc...

          Si - Ge - InGaAs - ex InGaAs - InAs - InSb - PbS - PbSe – HgCdTe


Detector Components + Pre-Amplifier Electronics

EOS specializes in integrating our broad product line of detector components with preamplifier electronics, creating receiver modules to ccommodate almost any IR measurement requirement, from laboratory experimentation to industrial OEM applications.

The compact TO-packaged units offer the user the convenience and performance advantages of having the photodetector and amplifier in as close proximity as possible, minimizing EMI and microphonics.


The versatile H-seriesunits offer the user a group of interchangeable detectors which provide optimal coverage of the UV-VIS-NIR, -MWIR, -LWIR wavelength regions.


The cryogenic detector/amplifiersoffer the ultimate in sensitivity for any given wavelength range as well as maximum immunity to EMI, microphonics, and accidental mishandling.

These products insure the proper matching of the photodetector and amplifier characteristics for maximum performance. All the receiver modules work well with our

Support Electronics.


EOS categorizes the Receiver Modules into three main sub-categories as follows:


The compact TO-packaged units offer the user the convenience and performance advantages of having the hotodetector and amplifier in as close proximity as possible, inimizing EMI and microphonics. Hybrid photodiode/amplifier modules are available using any of our room temperature or TE-cooled photodiodes. A 4-pin TO-5 is used for fixed-gain, un-cooled units with active areas up to 3mm diameter. TO-8 packages are used for larger area devices and for applications where user selectability in terms of gain, bandwidth, and offset is desirable.

TE-coolers for temperature stabilization and/or performance enhancement can also be added in the TO-8 packages and in the larger T-5 OFHC copper housings. hotoconductor/amplifier modules are available containing PbS, PbSe and HgCdTe devices. These use TO-8 or T-5 packages for either room temperature or TE-cooled operation. The units are AC-coupled and can be provided with user selectable bias, gain, and bandwidth.


H - Series Receivers

Modules containing any of the EOS photodetector components are available in the versatile H-series housing with either current mode transimpedence amplifiers or low-noise voltage amplifiers.

From the users' standpoint, the modules are interchangeable; when coupled with the proper electronic, optical, and mechanical accessories, they provide a complete IR measurement capability. These housings are rugged and provide excellent mechanical stability for different mounting arrangements. Both room temperature operating and TE-cooled units are available.


The thermal characteristics of the package are good enough that in many cases the TE units do not require additional heat sinking. Optimization of the gain and bandwidth is done at the time of order to specific user requirements and the output signals are compatible with signal processing electronics such as ADCs, lock-in amplifiers, oscilloscopes, and DVMs.

Options include: optical filters, filter holders, fiber-optic connectors and custom multi-stage amplifiers.

Cryogenic Receivers 

The cryogenic receivers offer the ultimate in sensitivity for any given wavelength range as well as maximum immunity to EMI, icrophonics, and accidental mishandling. The standard EOS dewars, side-viewing or down-viewing, can be rovided with built-in amplifiers for any of the photodiode or hotoconductor components.

Depending on the specific detector and sensitivity requirements, parts of the amplifier may be cooled along with the detector. These EOS modules are unique in the industry in providing the ultimate in sensitivity, EMI immunity, and low microphonic noise. The standard units contain switchable gains, BNC outputs, and shielded power connections. Custom options include offset control, additional gain control, and multi-stage amplifiers.



Power Supplies, TE-Controllers, Pre-Amplifiers, Data Acquisition Systems, etc...

EOS manufactures support electronics for our detector products. This product line includes power supplies, preamplifiers, temperature controllers, lock-in amplifiers and a variety of custom data acquisition systems.


One of the great advantages of these units is that the end user can directly plug them into any EOS receiver module without additional wiring. EOS electronics are designed for extremely low noise operation resulting in optimum detector system performance. All power supplies are CE Marked.

Below you will find our standard accessories:

PS – 1 Low Noise Power Supply 

The PS-1 provides very low noise, +/- 15VDC. This unit operates with all EOS receiver modules, including all biasing requirements. In addition, the PS-1 works well as a general purpose, dual polarity aboratory power supply. Unless otherwise specified, the factory setting is 120VAC. The voltage is selected by rotating the small board beneath the fuse to read either 120 or 240. EOS can customize the number of channels of the PS-1 to power several receivers at once. Please review the one, two, and five channel specifications below.




PS - 1B Ultra Low Noise - Battery Operated Power Supply

The PS-1B is an ULTRA LOW NOISEbattery operated power supply designed primarily for powering all EOS' receiver modules and preamplifiers. The PS-1B will operate as a standard PS-1, or as a battery powered supply. In the PS-1 mode the output will be +/- 15VDC; in the battery powered mode, the output will be +/- 12V. This unit can be customized up to 2 channels.




PS /TC-1 Power Supply / TE Controller

The PS/TC-1 combines the low noise +/- 15VDC power supply for the amplifiers with a closed-loop proportional controller and power supply for all the TE coolers offered with EOS detectors. The PS/TC-1 was designed specifically for the thermoelectric cooler control characteristics but can also be used a general purpose power supply.


One of the great advantages of the PS/TC-1 is that the end user can directly plug it into any TE-cooled EOS receiver module without additional wiring.



TC-2 Board Level Controller

This module is an OEM version of the TE cooler controller which can easily be designed into users' equipment. It operates from a 5VDC supply and features status indicators and a variable temperature setpoint.




AMPLIFIERS  EM-Series - LOG/LOG - Lock-In Amplifiers

In addition to the amplifiers integrated into our receivers, EOS offers a line of stand-alone amplifier modules. These units, which support both photodiodes and photoconductors, are available in multi-stage or multi-channel configurations.They offer a wide selection of gain/bandwidth characteristics. Custom designs are also available.




LIA/PS-1 Lock-In Amp / Power Supply

The LIA / PS-1 is a combination lock-in amplifier and low noise power supply which powers all EOS' receiver modules and interfacing to the receiver preamplifiers. In addition, the PS-1 works well as a general purpose, dual - polarity laboratory power supply.







Si - Ge - InGaAs - ex InGaAs - InAs - InSb - PbS - PbSe - HgCdTe

The EOS detector component product line consists of photodiodes and photoconductors of a variety of different starting materials, giving the broadest selection from one source in the industry. EOS offers several standard sizes in most detector types, and offers custom design service for non-standard requirements. Please consult factory if you need technical support for your application.

The products can be generally broken down into three wavelengths regions plus a specialty category that includes Position Sensors, 2-Color Detectors, and Quadrants.

UV - VIS / NIR includes InGaAs, ex-InGaAs, Germanium, and Silicon photodiodes that cover progressively from 0.2 to 2.6 microns.

NIR - MWIR includes InAs and InSb photodiodes as well as PbS, PbSe, and HgCdTe photoconductors that cover the 1 to 5.5 micron spectral range.

LWIR includes HgCdTe photoconductors and specialized pyroelectric and thermopile detectors that are used to cover the 1 to 40+ micron spectral range.

UV - VIS/NIR 200 nm - 2.5 microns

Components in this category are Silicon, Germanium, InGaAs, extended-InGaAs, and photodiodes that cover progressively from 0.2 to 2.6 microns.

These detectors operate at room temperature or with TE-Coolers and are housed in a variety of TO-Style packages.

Several standard diameters are available as well as specialty devices such as Si & InGaAs Quadrants, 2-color detectors, multi-element detectors and PSDs.


Click here for part numbers


NIR – MWIR 1.0 - 5.5microns

Detectors included in this category are InAs and InSb photodiodes as well as PbS, PbSe and HgCdTe photoconductors that cover the 1 to 5.5 micron spectral range. Room temperature, TE-Cooled and Cryogenic packages are utilized, depending on sensitivity requirements. A variety of standard and custom sizes are available.


Click here for part numbers


LWIR 2 - 40 microns

Detectors included in this category are HgCdTe Photoconductors and specialized Pyroelectric and Thermopile detectors that are used to cover the 1 to 40+ micron spectral range. A variety of standard sizes and custom geometries are available.


Click here for part numbers



To expand the line of position sensing devices, EOS has added several quadrant detectors to our standard product line. These are high performance devices and come in room temperature or TE-Cooled TO-Style packages. The Quadrants have been added to the line of position sensing products including Silicon for the UV-VIS and InGaAs for 1 - 1.7 µm. Applications include laser beam steering and tracking.


Click here for part numbers / Click here for Operating Notes



The G-series Germanium and IGA-series InGaAs Position Sensors are a family of lateral effect photodiodes sensitive in the near-IR region of the spectrum - from 800nm to 1700nm. They offer continuous position sensing capability over a selection of active sizes and are available as components or as integrated photodiode/preamplifier subassemblies.


Click here for part numbers



EOS manufactures two-color detector components, each with a different spectral response, mounted in a sandwitch style configuration. This geometry has its' top photodetector with normal operating characteristics. However, it also acts as a long wavepass spectral filter over the bottom detector.