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 reported1-3; 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 AmericaPDF Article