Compact linearized optical FM discriminator

A new type of optical frequency discriminator is proposed and analyzed numerically. The discriminator is based on a linear variation of the reflectivity of an optical reflection grating versus frequency. The proposed chirped grating has a constant /spl kappa/ or index variation and the reflectivity versus optical frequency is tailored by employing a grating with a spatially varying chirp parameter. Integration with a frequency-modulated distributed feedback laser would yield an efficient photonic RF transmitter.