Reconfigurable Dispersion Equalizer Based on Phase-Apodized Fiber Bragg Gratings

We present a novel dispersion equalizer design for the compensation of chromatic dispersion and chromatic dispersion slope in WDM systems. The device is based on a cascade of complex quasi-periodic chirped fiber Bragg gratings. We show that the use of a low chirp results in the distribution of the resonating cavities along the optical fiber length, which allows reconfiguration of the spectral characteristics by the application of a temperature profile. This paper exposes in detail the numerical techniques used in the optimization of the fiber Bragg grating filters taking into account fabrication imperfections. We present a specific design for a 32-channel dispersion equalizer for 10 Gbit/s and a 50-GHz channel spacing. We examine the spectral characterization of a device fabricated using a phase-apodized mask for various settings of the chromatic dispersion profile. We demonstrate a tuning range of +/- 800 ps/nm over a bandwidth of 30 GHz. On average, the standard deviation of the phase ripple was below 0.1 rad. Finally, we evaluate the performance of this device by bit error rate measurements.