W. Glatt et al., OPTICAL PSK HOMODYNE SYSTEM USING A SWITCHED RESIDUAL CARRIER FOR PHASE SYNCHRONIZATION, Electronics Letters, 32(15), 1996, pp. 1386-1387
In this new concept for a digital optical homodyne transmission system
, phase synchronisation of the receiver's local oscillator relies on a
n additional low-key phase modulation at the clock frequency. The fron
t-end uses a 180 degrees hybrid and is AC coupled.