Frequency response of a Fabry-Perot interferometer used as a frequency discriminator (semiconductor laser application)

The theoretically and experimentally obtained Fourier frequency responses of a Fabry-Perot interferometer used as an optical frequency discriminator are given. The frequency response depends greatly on the laser detuning from the fringe peak of the interferometer. Conditions optimizing the discriminator gain were obtained for a Fabry-Perot interferometer operated in reflection as well as in transmission. It is shown that the conversion gain is theoretically larger in reflection. For both modes, the bandwidth of the conversion increases as the laser is detuned from a fringe peak, and a resonance appears. The high-frequency slope is -20 dB/decade in reflection and -40 dB/decade in transmission.<>