200 MHz TTL-analog photodetector
Koheron PD200T is an InGaAs photodetector with a dual TTL-analog output. The analog output has a gain of 500 V/A and a 200 MHz bandwidth. The TTL output has 2.5 ns propagation delay, 1.3 ns rise time and 0.7 ns fall time. Trigger threshold can be adjusted with a precision trimmer.
|Wavelength range||900 - 1700 nm|
|Optical input power||0 - 2 mW|
|Noise Equivalent Power||30 pW/√Hz (at 100 kHz)|
|Small signal bandwidth||200 MHz at 3 dB|
|Impulse response||2 ns (FWHM)|
|Transimpedance gain||500 V/A (Hi-Z), 250 V/A (50 Ω)|
|Analog output impedance||50 Ω|
|Analog output dark offset||10 mV|
|Analog output current max||80 mA|
|Analog output voltage||3 Vpp (Hi-Z), 1.5 Vpp (50 Ω)|
|Analog output slew rate||400 V/µs (50 Ω), 600 V/µs (Hi-Z)|
|TTL rise / fall time||1.5 ns|
|Logic low||0.1 V (max. Hi-Z), 0.05 V (max. 50 Ω)|
|Logic high||2.6 V (min. Hi-Z), 1.3 V (min. 50 Ω)|
|TTL output current max||20 mA|
|TTL output impedance||50 Ω|
|Power Supply||3.7 - 15 VDC|
|Outside Dimensions||48 mm x 53 mm x 14 mm|
|Mechanical details||Compatible with M6 metric breadboards (25 mm spacing)|
We operated the Koheron LD100 laser in pulsed-mode (width of 10 ns, pulse period of 100 ns, 10 Vpp modulation). The laser average output power was 850 µW. Half of this power was used to feed the PD200T. Trigger threshold was adjusted to 1.0 V. The figure below shows the analog output (in blue) and the TTL output (in purple) observed on an oscilloscope:
Propagation delay between the analog and the TTL output is about 2.5 ns. TTL rise and fall times (10 to 90 %) are 1.3 ns and 0.7 ns, respectively.
We modulated the Koheron LD100 laser with a 100 Mbps pseudo random binary sequence (PRBS) shown in yellow in the figure below. The green curve represents the modulation detected by the 100 MHz photodetection of the LD100. The analog and TTL output of the PD200T are shown in blue and red, respectively.
The 25 ns delay between the laser modulation (in orange) and the PD200T analog output (in blue) corresponds to the 5 m fiber between the laser and the PD200T.
- 2: FC Photodiodes