Performance evaluation of a high-birefringence linearly chirped grating for PMD compensation in WDM/ IM-DD transmission system

We analytically evaluated the performance of an adjustable polarization mode dispersion compensator based on a 2-cm long high-birefringence linearly chirped fiber Bragg grating and simulated a 4-channel WDM/IMDD system using this compensator. The device can adjust differential group delay in a linearly continuous way without affecting wavelength outside the bandwidth. The various properties of the device such as relative group delay, reflectivity, differential group delay etc. are investigated in terms of wavelength and stretching ratio. Results show that under stretched condition; the device generates a time-delay between fast and slow polarization axes that is adjustable from 0 ps to 55 ps and is tunable within 2.4 nm wavelength range. Through simulation, it is also found that the power penalty is reduced from 7.10 db to 4.5 dB at a mean DGD 40 ps for a 4-channel 10 Gb/s WDM system when no stretched is applied on the grating.