COMBINED FREQUENCY AND AMPLITUDE-MODULATION FOR THE STARNET WDM COMPUTER-COMMUNICATION NETWORK

STARNET is an experimental wavelength-division multiplexed computer co mmunication network that makes use of combined modulation of a single transmitter laser to implement a virtual-ring control sub-network and a reconfigurable high-speed sub-network over a passive star architectu re. In this letter, we demonstrate a new technique of combined modulat ion that works by direct frequency-shift keyed (FSK) modulation and ex ternal amplitude-shift keyed (ASK) modulation of a semiconductor laser , By adjusting the amplitude modulation depth to 0.8, both the 125 Mb/ s ASK receiver and the 1,244 Gb/s FSK receiver operate with equal bit- error ratios less than 10(-9) for a received signal power of -24 dBm.