EFFECT OF TRANSMISSION THROUGH FIBER GRATINGS ON SEMICONDUCTOR-LASER INTENSITY NOISE

The effect of transmission through a fiber Bragg grating on the relati ve intensity noise of semiconductor laser light is investigated. We fi rst present a model of the grating as a linear frequency discriminator that exchanges correlated power between frequency noise and intensity noise caused by spontaneous emission. This correctly explains observe d increases in intensity noise of up to 30 dB at low frequencies, obey ing an inverse-square frequency dependence. Next, we show that there e xist conditions under which a grating can reduce intensity noise and t hat these are determined by the phase relationship between correlated intensity and frequency fluctuations. Finally, we demonstrate a 2 dB r eduction ol intensity noise at frequencies up to 15 GHz, and present a numerical calculation based on the complex transmittance of the grati ng that correctly describes the effect of grating dispersion. (C) 1997 American Institute of Physics.