Abstract

In an optical-frequency-division-multiplexing (FDM) transmission system, the transmitter with a laser diode (LD) frequency control system is used to maintain the LD frequency allocation and stability. To date, several frequency-locking systems have been reported^1-3; among them, a spectroscopic method¹ has the advantage in wide capture range and modulation signalindependent controllability. However, the full channel range was limited by the scanning range of the sweep LD. In addition, the long-term stability of the control system depends on the long-term stability of the sweep LD emission frequency. We report a novel laser frequency locking scheme which extends the full range of the frequency-locked channels and the long-term frequency stability, utilizing a widely frequency-tunable DBR DC-PBH LD⁴ and a Fabry-Perot resonator.

© 1988 Optical Society of America