Rotation angle optimization of the polarization eigenmodes for detection of weak mode coupling in birefringent waveguides

Abstract

White light interferometry has been adopted to measure distributed polarization coupling in high-birefringence waveguides. Since the coupling mode is weak compared to the exciting mode, the contrast ratio of the interferogram is very low. This will increase the difficulty of direct detection of the polarization coupling intensity. By rotating the angle between the polarization eigenmodes and the principal axis of the linear polarizer from 45 degrees to 85 degrees , the contrast ratio of the interferogram can be improved more than 10 times. As a result, the measurement sensitivity can be improved more than 100 times.

Influence of ghost coupling points on distributed polarization crosstalk measurements in high birefringence fiber and its solution

“…According to Eqs. (10) and (13), the intensity of the ghost coupling point I 4 can be written as [14] h ghost…”

“…(25) and (26) we know that h Amis and h Bmis will increase if φ > 45°. Under this condition, the measurement sensitivity can be improved [14]; however, the ghost coupling point will rise also.…”

Photonic sensors review recent progress of fiber sensing technologies in Tianjin University

“…In stress-induced PMF, polarization mode coupling will caused by a range of environment parameters, such as external transverse forces [7], distributed stress [8], position, and strain [9]. The coupling coefficient has a definite relationship with these parameters.…”

“…The researches of Tianjin University are always focused on fiber optical sensing technology and the related detection technologies for many years. And we have received remarkable results in the field of high temperature sensor [1,2], parallel demodulation of extrinsic Fabry-Perot interferometer (EFPI) and fiber Bragg grating (FBG) sensors [3,4], gas concentration sensing technology based on intra-cavity [5,6], distributed sensing based on polarization maintaining fiber (PMF) [7][8][9][10] and so on. Tianjin University has taken on Natural Science Fund of China, 863 project, major programme of National Development Planning Commission, large project of Tianjin, and other provincial or ministerial funds for more than twenty research projects.…”

Enhancement of signal-noise-ratio in a distributed polarization mode coupling detection system

“…WLI based on optic sensors are immune to electromagnetic interference, suitable for harsh environments and compatible with optical fiber data communication systems. It also has been used to detect distributed polarization-mode coupling (DPC) in high-birefringence fibers (HBFs) to improve the measurement accuracy [1,2,5] . Due to the drawbacks in manufacturing process and environmental perturbations, distributed polarization coupling dose exist in HBFs [11,12] .…”