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Our address is
Rhythm Optoelectronics, Inc.         244 Holovna Str., Chernivtsi, 58032 UkrainePhone: +380 3722  426 13, 453 10, 426 17,                              Fax:    +380 3722  426 33 rhythm@chv.ukrpack.net
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  • The advanced technology of semiconductor photosensitive chalcogenide (PbS and PbSe) films has been developed. On the basis of this technology design engineering and manuafcture of high-quality photodetectors (PD) and photodetector preamplifier modules (PPM) operating in (1 - 5) µm spectral region at the earliest possible dates are proposed.
  • A structural diversity, high parameters and relative cheapness of the devices developed provide their wide use in devices and systems for the following:
  • - remote temperature sensing within the limits of (300 - 2000) °;

    - flame sensors in fire warning systems;

    - control of thermal state and forecast of emergency situations in storages for free-flowing bulk materials including self-ignitable ones (coal, grain, cotton, arboreal sawdusts, etc.);;

    - control of the state of heat-resistant walls, diagnostics of faults in cooling systems and emergency situations forecast in blast furnaces, converters and other metallurgical installations;

    - systems of thermodiagnostics in medicine;

    - space exploration;

    - thermal control of electronic devices assembling quality;

    - control of thermal operation modes of equipment in steam power plants and atomic power equipment, steam generators, chemical equipment and other power-intensive and fire-hazardous technical installations.

  • Our devices are characterized by:
  • - detectivity and voltage responsivity high values;

    - application of built-in thermo-electric coolers (TEC), if necessary, their parameters being compared favourably with foreign analogs;

    - enhanced optical noise immunity owing to application of interference and semiconductor cut off light filters (λlim = (1 - 4) µ);

    -enhanced electric noise immunity owing to screening of a metallic package and the presence of built-in low-noise preamplifiers in PPM, made by hybrid-film technology;

    - extraordinarily low figure of merit straggling in multi-element structures (variation coefficient ω ≤ 0,1 - 0.2 across a 128 - element structure);

    - a strong cable standing up to forty thousand bends;

    - a structural diversity and relative cheapness at high quality level.

  • Over thirty years of production, thousands of our products found application in pyrometers, flame sensors in fire warning systems, automatic operation control of gas caldrons, etc. Single- and 128-element PPM with ultimate parameters are used in space IR specrometers installed on the interplanet space stations, in particular, the «Mars-96 » and the «Mars- Express».

Efficiency and quality of our products will recover your money spent a hundredfold!!!


  • Main photoelectric parameters of majority of PD and PPM of our production compare favourably with, or exceed values, declared in the catalogues of leading foreign companies manufacturers of analogous products.
  • PD (PPM) responsive element (RE) size, mm 0.1 - 10.
  • Main photoelectric parameters and characteristics are given in the table below.
Parameter (Characteristics) Name
Material of Photodetector Responsive Element
Temperature, °C
Spectral range (Δλ), µm
0,8 - 3,0
0,8 - 3,5
0,1 - 4,4
0,1 - 4,8
Peak spectral response wave-length (λmax), µm
2,5 ± 0,2
2,8 ± 0,2
3,5 ± 0,3
4,0 ± 0,3
Time constant (τ), µs
Dark resistance (Rd), MOhm
Voltage responsivity (Sv), V/W
(1 - 5)·104
(1 - 5)·105
(1 - 5)·103
(1 - 5)·104
Detectivity (D*λmax, 1010cm ·Hz½·W-1) at modulation frequency (fmod), Hz
5 - 15
20 - 70
0,5 - 1,5
2 - 8
  • The set of D*λmax , Sv, τ, λmax parameters may be optimized for a particular task at the expense of technological potential to control processes of photosensitive layers formation. According to experts from companies such as of NII PPH (Moscow, Russia), Vavilov GOI (St Petersburgh, Russia), UPI (Yekaterinburgh, Russia), Elettronica (Italy), Graseby Infrared (USA), products of Rhythm Optoelectronics Inc. measure up to the best world analogs as to their technical level.


  • make separate batches of devices according to technical requirements of the customer during 1 - 6 months;
  • carry out R&D for program-oriented devices development with the specifications set and further commercial production. The time interval is 1 - 2 years;
  • develop and produce as soon as possible the analogs of IR photodetectors, manufactured by foreign companies (FSA type - any; FR1-3, FR1-4, FR-SS-138; FSV-16, FSV-17, FSV-18, FSV-19; SF4 - any; FUO-611, FUO-612, FUO-613, FUO-614; FUL-611, etc.);
  • make PD and PPM of different construction and circuitry for the spectral range of (1-5) µm execution, element number from 1 to 128 on one substrate.


  Detection of optical radiation by a lead chalcogenide-based photoresistor depends on the change of material conductivity influenced by optical radiation.

  To detect the change in photodetector photoconductivity, it is connected in the circuit which consists of a direct voltage source and a load resistor, the photosignal shows up as a change of voltage across the load resistor. Due to its low value the signal in most cases is not suitable for direct applications.

  The signal should be amplified, maximum signal/noise ratio provided, being achieved on execution of the following recommendations:

  -resistance of the load resistor should be equal to dark resistance of the photodetector;

  -passband of the detecting electronic circuit should be minimum necessary;

  -noise voltage of the detecting electronic circuit should be smaller by a factor of three than noise voltage of the photodetector, not less;

  -the photoresistor (FR) and the electronic circuit should be proofed against the influence of optical and electric interferences.

  Typical photoresistor connection circuits are given in Fig. 1 - 3. The diagram in Fig. 1 is optimum for operation in equipment with unipolar power supply and allows providing a high photosignal voltage gain.

  The diagram is good as there is information in the output signal about the direct voltage value in the point of connection and the load resistor. This information can be used for thermal stabilization of the device to reveal the signal of error.

   Fig.1. FR connection circuit in the equipment with unipolar power source.

   In such a FR connection the output signal voltage is defined according to equation 1.

   Vc = ·Sv(R2/R3 + 1),      (1)

where is radiation flux;

Sv is voltage responsivity.

  Thus frequency f = 2πR3·C.

  The diagram in Fig. 2 should be preferably used in equipment with a two-polar power souce.

  The presence of a dividing capacitor allows eliminating the influence of FR temperature drift and permanent background radiation on the mode of the amplifier operation.

   Fig.2. FR connection diagram in the equipment with a two-polar power source.

   In such a FR connection the output signal voltage is defined according to equation 2.

   Vc = ·Sv(R4/R3 + 1),      (2)

  Thus frequency f = 2πR2·C.

  The diagram in Fig. 3 should be preferably used in the equipment with a two-polar power source operating in a narrow ambient temperature range.

  Fig.3. C and D diagrams of FR connection into the equipment source operating in a narrow temperature range.

  Their basic advantages consist in the minimum of completing items applied and possibility to operate with FR, remote from the amplifier at high frequencies of optical radiation modulation..

  At such methods of connection, it is necessary to execute the condition of E <Uoutput.max·Rf/R.

  As to their characteristics, A D connection diagrams are identical.


  When designs of devices with the application of lead chalcogenide-based photoresistors are developed, it should be taken into account that due to high resistance of (R + R1) circuit, interferences and pick-ups may penetrate to the entrance of the amplifier across the E circuit. This why, please, provide a simple RC-filter in the circuit and place it near the photodetector.