Question

which of the following can contribute to laser instability leading to a high BER value?

low insertion loss

high return loss

low return loss

high insertion loss

Answer 1

A low return loss sometimes causes instability in laser operation which may cause noise due to emission of different frequencies instead of single frequency.

In laser applications , back reflected light may increase bit error rate because the light which reflected back will emits multiple frequencies which is violating laser monochromatic characteristics and information at the transmitter side will not match with the information which is reflected back there by causing instability. Hence it is better to have high return loss than low return loss to avoid instability there by bit error rate BER also decreases.

Conclusion:C) Low return loss will cause instability leading to high BER.