Wavelength-Dependent Polarization Beam Splitter Based on Birefringent Tapered Multicore Fiber

A newPolarization Beam Splitter (PBS) is proposed by introducing an outer substrate, different from the sophisticated design on the structures themselves. The PBS is fabricated by tapering a multicore fiber (MCF) and assembling with a PDMS substrate, with easy handling and high feasibility. The periodic oscillation transmission demonstrates the interference between the center- and side-core modes with a phase difference of π/2. The polarization dependence of the periodic spectra is observed. The intensity distribution can be modulated either in the center-core or side-cores by adjusting the polarized angle or the wavelength. For specified wavelength, the TE and TM mode can be split into different cores by introducing asymmetry from the PDMS substrate to produce a birefringent tapered MCF. The maximum polarization extinction ratio (PER) of the center-core and side-cores is achieved to be 26 dB and 20 dB for specified wavelengths, respectively. The experimental results show that the center- and side-core have different preservation capabilities of different linear polarized light, corresponding to periodic wavelength. The simulated models are computed by using Rsoft BeamPRO and COMSOL Multiphysics to clarify the fundamental principles of the observed phenomena. The simulated spectra are consistent with the measured spectral response. The proposed structure can serve as a potential PBS with high PER and easy feasibility in various MCF-based applications owing to its capability of the wavelength-dependent and polarization-dependent splitting.