Abstract

We demonstrate that an inexpensive, uncooled Fabry–Perot laser with no isolator is easily capable of transmitting 60 channels of 2-Mbit/s quadrature-phase-shift-keyed (QPSK) data. These lasers are far less expensive than the extremely linear distributed-feedback (DFB) lasers commonly used to transmit analog AM-VSB signals. Others have evaluated the feasibility of transmitting digital information on subcarriers in a hybrid AM-VSB-digital system. These systems used very linear lasers with isolators in order to meet the stringent requirements of the analog channels.^1-4 A previous study of QPSK transmission used a Fabry–Perot laser, but it suffered from a BER floor when multiple channels were transmitted.⁵

© 1995 Optical Society of America