Tunable Polarization Mode Dispersion Research Articles

Dual-core photonic crystal fibers for tunable polarization mode dispersion compensation

A novel type of dual concentric core photonic crystal fiber (PCF) is proposed and theoretically analyzed, aiming at the design of tunable dispersive fiber elements for polarization-mode-dispersion (PMD) compensation. The adjustment of the fiber's geometrical birefringence through the proper selection of structural parameters leads to very high values of differential group-delay (DGD). Moreover, the value of DGD can be dynamically tuned by infiltrating the outer core capillaries of the PCF with an optical liquid, which allows for the thermal control of its refractive index. Such fibers are envisaged as tunable dispersive fiber elements for PMD compensation or emulation modules.

Tunable PMD compensator based on highbirefringence

The simple structure of a tunable polarization mode dispersion (PMD) compensator based on a cantilever beam and a high-birefringence linearly chirped fiber Bragg grating is proposed. A cantilever structure is used to introduce a linear strain gradient on the grating, and we can tune the compensated differential group delay (DGD) at a fixed signal wavelength just by changing the displacement at the free end of the beam. Based on numerical simulations, the performance of the cantilever structure as a PMD compensator is assessed for 10-Gbits/s nonreturn-to-zero transmission systems with a large DGD. With this compensator, a significant improvement of system performance can be achieved in the eye pattern of a received signal.

Wide bandwidth, large, and tunable polarization mode dispersions in multilayered omnidirectional reflectors

We numerically demonstrate the generation of large, broadband, and tunable polarization mode dispersion (PMD) with omnidirectionally reflecting dielectric stacks with embedded cavities. Both first-order and second-order polarization mode dispersion can be generated by similar configurations. Our examples show that the first-order PMD can be tuned from 0 to 30 ps over an 80 GHz bandwidth and second-order PMD from 0 to 50 ps/nm can be generated over a 100 GHz bandwidth. We also show that in our configuration there is no significant modal distortion of the light beams when the beam diameters exceed 3.5 mm.

A novel adjustable PMD compensation using sampled Bragg gratings with uniform grating period

We propose a novel solution for linearly tunable polarization mode dispersion (PMD) compensation by sampled Bragg gratings fabricated with uniform-period phase masks. This all-fiber PMD compensation technique is cost-effective and flexible in designing the differential group delay (DGD) profile. Based on numerical simulations, the efficiency of this PMD compensator is assessed for the 10 Gb/s NRZ transmission system with large DGD. With this compensator, a significant improvement can be achieved in the eye pattern of the received signal.