Performance of a baseband carrier-sense circuit for optical packet networks

We have characterized our baseband carrier-sense circuit (BCSC) for use in future optical CSMA packet networks. The range of received optical power (ROP) for reliable operation at the circuit is bounded at the lower end where transmission collisions occur and at the higher end where transmission efficiency is compromised. A low low-pass filter (LPF) bandwidth benefits sensitivity, while a high LPF bandwidth benefits transmission efficiency. We found that for our BCSC implementation, an optimum LPF bandwidth exists that maximizes the operating range of ROP, but that the bandwidth dependence of this range is less than 1 dB between 100 kHz and 1 MHz.