Impact of local oscillator intensity noise in coherent optical POLSK heterodyne/homodyne receivers

The impact of local oscillator intensity noise on the performance of POLSK (polarization-shift-keying) heterodyne/homodyne receivers is theoretically investigated, and the optimum local oscillator power is found. The local oscillator power has an optimum value to minimize the received signal power. At optimum local oscillator power, which is independent of bit-rate and signal-to-noise ratio, both receivers have the same sensitivity. The optimum local oscillator power for the homodyne receiver is 3 dB higher than that for the heterodyne receiver, while the homodyne receiver is significantly less sensitive to intensity noise in the region of high local oscillator power than the heterodyne receiver.>