Why do we use forward bias in optical sources ?
Why do we use reverse bias in optical detector?
Answers
The photodiode is reverse biased for operating in the photoconductive mode. As the photodiode is in reverse bias the width of the depletion layer increases. This reduces the junction capacitance and thereby the response time. In effect, the reverse bias causes faster response times for the photodiode
Answer: Forward biasing means putting a voltage across a diode that allows current to flow easily, while reverse biasing means putting a voltage across a diode in the opposite direction. ... This is useful for changing AC current to DC current. It has other uses in manipulating electronic signals as well
The reverse bias causes the potential across the depletion region to increase and the width of the depletion region to increase. This is ideal for creating a large area to absorb the maximum amount of photons. The response time is reduced by the reverse bias by increasing the size of the depletion layer.