preserved in the fiber. PMFs are used in special applications, such as in fiber
optic sensing and interferometry.
1.2.9 Photosensitive Fiber
FBG is a means to increase optical fiber transmission capacity. It is a
technique for building optical filtering functions directly into a piece of optical
fiber based on interferometric techniques. Exposing photosensitive fiber to deep
UV light through a mask forms regions of higher and lower refractive indices in
the fiber core. The number of transmitted channels is limited by the wavelength
separation between each Bragg grating. The quality of the Bragg grating depends
heavily on the photosensitive fiber used to write the grating.
When the core of a photosensitive optical fiber has been created using
dopants, ...