Phase noise research
Ong, Hueh Chuah.
Date of Issue1997
School of Electrical and Electronic Engineering
The broad linewidths of semiconductor lasers are unacceptable for various applications which require high spectral purity, eg. interferometry, laser spectroscopy and coherent optical detection. The only semiconductor laser light sources available at the beginning of 1980s were Fabry Perot laser diodes oscillating in multilongitudinal modes with a linewidth as wide as several tens of gigahertz, which was far away from the above requirement. Roughly speaking, the required linewidth of a light source for the realization of coherent lightwave communication systems is about lMhz. This is due to the required coherence between the light from the transmitter and local oscillator sources. As the phase noise is due to spontaneous emission in the laser diode, it has direct impact on the IF detection mechanism.
DRNTU::Engineering::Electrical and electronic engineering::Control and instrumentation
NANYANG TECHNOLOGICAL UNIVERSITY