Abstract:
An avalanche photodiode (APD) detector is a sensitive photon detector
when operated near breakdown voltage to achieve the highest internal
gain. Due to low level of output from the APD, it is required to add
trans-impedance amplifier (TIA) and cascaded stage of post-amplifier
(PA) for amplification in addition to bias supply circuit for the design
of optical receiver. The noise contribution from each component of
the optical receiver is required to perform for low-level light detection
application. At higher operating gain, the APD also contributes to the
total noise level. In this paper, we have described the detail about circuit,
simulation of the equivalent circuit of detector, detail noise calculations
with bandwidth of more than 1 MHz, and frequency response of the
receiver. The in-house proto-type circuit is successfully tested with
APD for the detection of photons given from the fibre-optic with
the laser diode as an optical source in laboratory. We believe that the
work described here will find application in medical instrumentation,
automobile industry, and signal communication area.
