We demonstrate a high-power pulse laser with extremely high pulse extinction ratio (ER). This laser module is designed
for the experiment of 217 km long distance photon-counting optical time-domain reflectometry (ν-OTDR) using an upconversion
single photon detector. The maximum peak power of laser pulse is over 24dBm with an extremely high pulse
extinction ratio of more than 100dB.
It’s difficult to detect the ultra-weak light with conventional method. By using APD, we can transform the weak light to feeble current. And it’s a great challenge to design the low noise and high gain front-end electronics of InGaAs photoelectric detector. The first step to design is to calculate the noise margin of system and the bandwidth of system. And then, choose the appropriate amplifier of the system. Finally, design the whole circuit which is working stably. In this paper, we bring about a whole process of design and simulation of the front-end electronics of InGaAs photoelectric detector in theoretical ways.