Characterization of D-fibers and optical waveguides using scanning near field optical microscopy and atomic force microscopy

Abstract

The D-fiber is the same as a standard circular fiber with the exception that it has a D-shaped cladding. In order for this fiber to be used in sensing applications, both this evanescent and propagating field of the fiber must be well characterized. The near field microscope was used to measure both the propagating field at the cleaved end face of the D-fiber and the evanescent field near its flat edge. Before the D-fiber can be accurately modeled, the exact geometry of the fiber must be known. To obtain this information, a technique utilizing differential fiber etching and atomic force microscopy (AFM) was used. The profile obtained by the AFM was in excellent agreement with the calculations..