Patent ID: 6826371
Filing Date: 2004-11-30
Classification: H04L

Abstract:
A communication system for transmitting multi-rate data signals between a transmitter and a receiver, the communication system comprising:a transmitter including a modulator for modulating data signals having different data rates defining modulated data signals and continuously transmitting said modulated signals over a predetermined medium, said transmitter configured to modulate said data signals by differential phase shift keying (DPSK); and a receiver for receiving said modulated signals, said receiver including a single demodulator for demodulating said modulated signals; said demodulator including a single optical DPSK demodulator which includes a first coupler for dividing the incoming optical modulated data signals into two unequal light paths such that the optical path delay between said paths is one data bit period; a second coupler for recombining the optical signals from the unequal light paths; a switched filter circuit optically coupled to said demodulator and said switched filter circuit including a plurality of filters, each filter being tuned to a different data rate; and a clock and recovery circuit for recovering the data and clock signals.