Abstract

Direct optical phase modulation of DFB lasers [1] is interesting for multi-Gbit/s lightwave communication since it avoids the wavelength chirping of direct on-off intensity modulation without the increased systems complexity and loss associated with external modulation. The compact optical spectrum of DPSK modulation would minimize systems degradations due to fiber chromatic dispersion. A recent analysis indicates that direct DPSK modulation may produce superior performance over FSK modulation for heterodyne transmission at 10 Gbit/s over conventional single-mode fiber [2]. Furthermore, DPSK signals can also be directly detected after optical demodulation with an interferometer. Thus the DPSK signal format can also be used for highspeed direct detection systems.

© 1990 Optical Society of America