Analysis of the responsivity of silicon p-i-n photodiodes to Nd:YAG laser pulses

The carrier transport equations for a silicon p-i-in photodiode were linearized and analytic solutions of the responsivity were obtained for a step function of weakly absorbed radiation. The solutions were used for the calculation of the responsivity to Q-switched pulses from a Nd:YAG laser. The use of p-i-n photodiodes to detect mode locked pulses by taking advantage of the long period between pulses is shown to be feasible if the pulse shape does not have to be resolved.