When it comes to selecting a photoreceiver for measuring fast and small optical signals FEMTO® has plenty of options. All versions include the choice of an integrated Si or InGaAs PIN photodiode. Here’s a run-down on their receiver options:
FWPR Ultra High Sensitivity and Very Low Noise
This femtoWatt photoreceiver combines selected PIN diodes with a specially designed transimpedance amplifier, providing gain up to 1012 V/A and ultra-low noise with an NEP of 0.7 fW/√Hz @ 960 nm (for Si) and 7.5 fW/√Hz @ 1550 nm (for InGaAs). It is possible to measure directly optical powers as low as 50 fW without any further averaging circuitry. Applications include photon counting, NIR spectroscopy, fluorescence, electrophoresis and chromatography.
LCA Low Noise Current Amplifier with 107 V/A Transimpedance Gain
FEMTO combined their proven and outstanding low noise current amplifiers with state of the art photodiodes resulting in a minimum NEP as low as 75 fW/√Hz that allows for detection of optical signals in the nanoWatt range without further averaging. Applications include general purpose opto-electronic measurements, optical front-ends for oscilloscopes, A/D converts and lock-in amplifiers.
HCA-S High Sensitivity and High Bandwidth
Utilising high speed photodiodes and FEMTO®’s HCA series amplifiers, this series offers gain up to 1.9x104 V/A at 1550 nm (for the 200 MHz model) and 4.8x103 V/A at 1550 nm (for the 400 MHz model). The sophisticated DC coupled multistage amplifier design permits 1.8 ns rise time measurements when using the 200 MHz model and 1ns rise time with the 400 MHz model, with NEP of 40 pW/√Hz (at 800 nm and 100 MHz) and 24 pW/√Hz (at 1550 nm and 100 MHz). Optical signals in the microWatt range can be detected.
HSPR-X and HSA-X-S GigaHertz Technology
Here FEMTO® combine their GHz amplifiers with state of the art photodiodes to produce photoreceivers with remarkable performance. The HSPR-X and HSA-X-S offer ~2 GHz bandwidth, with an NEP of 11 pW/√Hz at a transimpedance of 5x103 V/A. MicroWatt optical power levels in the GHz range can be measured.
OE-200 Variable Gain
Designed for a wide range of applications requiring fast 500MHz from DC measurement of small optical signals, adjustable gain from 103 to 1011 V/A offering measurement between ~100 fW to 2 mW optical input power. This high sensitivity is achieved using a low noise design resulting in an NEP of 6 fW/√Hz. Additional features include switchable signal filters and opto-isolated remote control by PC.
OE-300 Variable Gain
Similar to the OE-200 however this model offers DC to 200 MHz measurement in order to incorporate large aperture photodiodes when using either free space optical beams or aligning fibre optic couplers. Switchable gains from 102 to 108 V/A allows for dynamic range measurement of 10 mW optical power.
