Chemical etching process for PANDA polarization-maintaining fiber in HiBi fiber loop mirror

Chemical etching process for PANDA polarization-maintaining fiber (PMF) in HiBi fiber loop mirror (FLM) is studied detailedly in this paper. The PMF is inserted into the FLM whose etched length is about 3cm. Due to decrease of the fiber diameter, the whole wavelengths of transmission dips shift to the short wavelength because of the reduction of birefringence when the PMF is etched. The result shows that the wavelength spacing between two interference minima increases from 19nm to 22nm when chemical etching ends, the thinned PMF is sensitive to the external environment and can be applied to many biochemistry sensing applications.