Integrated coherent transceivers for broad-band access networks

We proposed and demonstrated an integrated device with a simple structure that can perform both transmitting and receiving functions with very high receiving sensitivity. The device is composed of a tunable distributed-Bragg-reflector (DBR) laser as a local oscillator (LO) and an integrated detector. An FSK receiver sensitivity of -43.4 dBm at 108 Mb/s was obtained. Multichannel operating characteristics were studied and it was found that systems with an operation channel spacing of 3 GHz can be realized. This device can be operated with either half-duplex or full-duplex mode for broad-band access applications.