Recent Studies Of Laser Phase Noise In Optical Systems With Time Delays

In this paper we present results of recent theoretical and experimental investigations of the spectral shape of the phase induced intensity noise at the output of several optical recirculating configurations. These configurations include bulk-optics incoherent Fabry Perots, as well as fiber-optic delay lines. It is shown that whenever the system output consists of an infinite series of time delayed versions of the laser input field (recirculating structures), the RF power spectrum of the phase induced intensity noise is periodic with either notches or peaks at integral multiples of 1/(recirculating time), depending on the specific structure of the device. The relative phases of the output fields are shown to be the important factor which determines the shape of the period.