Define the function of photodetectors in fibre optic communication system.
Photo-detectors:
At the receiver end, conversion of optical signal into analog signal is being done with the help of photo detectors for example photodiode. The photo detectors are required to have
a. High quantum efficiency photon to electron (e-) conversion efficiency
b. Sufficient frequency response speed of response
c. Low dark current: low leakage current into a reverse biased diode within the absence of illumination
d. Low signal dependent noise capable to respond for signal quite than noise