Abstract

It has been pointed out by Armstrong, in 1966, that laser phase noise can be converted into intensity noise by passing the laser light through a dispersive structure such as an interferometer.^[1] This notion has been appreciated in optical communication^[2] and, more recently, in laser spectroscopy.^[3,4] Nevertheless, to our knowledge one of the most interesting predictions of Armstrong has not yet been verified. Here we refer to the prediction that laser light with a Schawlow-Townes or quantum-limited linewidth Δν_l will be converted into chaotic light when passed through a spectral filter with bandwidth Δν_f, if Δν_f <Δν_l. We report here experimental verification of this effect. We also extend the theoretical description beyond that given by Armstrong; this illustrates the potentiality of our experimental approach to distinguish between various statistical models of laser phase noise.

© 1992 IQEC