High Speed All-Optical Polarization Scrambler Based on Polarization Beam Splitting Delayed Fiber Loop

Polarization scramblers are widely employed to mitigate polarization fluctuation-related effects for optical signals propagating in fiber systems. We propose an all-optical polarization scrambler configuration based on a polarization beam splitting delayed fiber loop. By deteriorating the coherence of one beam, and controlling the intensity ratio of two orthogonal beams, the polarization scrambler operates in a chaotic regime. The effect on polarization scrambling of loop structure is tested by a home-made narrow-linewidth laser with linewidth of 500 Hz. We investigate the polarization scrambling performance for a commercial distributed feedback laser with linewidth of 3 MHz in various operating regimes. Scrambling speeds under chaotic regime reach 42 Mrad/s with a degree of polarization <0.1 at the maximum sampling rate of 100 MSa/s. We also characterize the dependence of the scrambling speed and average degree of polarization on delay fiber length and wavelengths within the C-band. The output performance of the proposed scrambler for scrambling 40 MHz and 6 GHz modulated signals are tested and waveform distortions are identified due to polarization scrambling.

Automated summary

In this paper, an all-optical polarization scrambler configuration based on a polarization beam splitting delayed fiber loop is proposed. The polarization scrambler operates in a chaotic regime by deteriorating the coherence of one beam and controlling the intensity ratio of two orthogonal beams. The effect of loop structure on polarization scrambling is tested using a narrow-linewidth laser and a commercial distributed feedback laser, and the dependence of scrambling speed and average degree of polarization on delay fiber length and wavelengths within the C-band is characterized. The performance of the proposed scrambler for scrambling modulated signals at 40 MHz and 6 GHz is also tested.