Distortion in angle-modulated links induced by ripple in fiber-Bragg-grating reflectance and delay characteristics

Ripple in the reflectance and delay characteristics of a linearly chirped fiber Bragg grating is shown to produce significant distortion in a wide-band angle-modulated fiber-optic link. Experimental results for a 7-GHz 39.4-km link where dispersion is compensated with a linearly chirped fiber Bragg grating show that the residual ripple in both the reflectance and delay contributes to harmonic and intermodulation distortion. Numerical modeling shows that the distortion is dominated by the random component of the delay ripple. The distortion is further quantified as a function of the ripple, the modulation index, and the modulation frequency.