Novel in-line fiber polarization beam splitter using high-birefringence fiber Bragg grating

This study proposes a novel fiber-type polarization beam splitter (PBS) based on a high-birefringence fiber Bragg grating (Hi-Bi FBG). The reflective and transmitted modes of the Hi-Bi FBG are used to separate the p- and s-waves of an optical signal. The experimental results show that a 36 dB extinction ratio can be obtained in the reflective mode. However, in the transmitted mode, the extinction ratio is just 4.78 dB since the reflectivity of the Hi-Bi FBG is only 34.75%. It is shown analytically that the extinction ratio in the transmitted mode can be improved to 20 dB by specifying a Hi-Bi FBG with a reflectivity of 99%. Finally, it is shown that the Bragg wavelength of the in-line fiber PBS can be tuned electrically to comply with the working wavelength.