ABSTRACT
A Bragg grating acts as a filter that reflects light at the Bragg condition, which depends on the grating period. To make a tunable Bragg grating requires the ability to change the grating period. Since polymers have both a larger thermal expansion coefficient and are less stiff than glass fibers, it’s possible to make temperature-or stress-tuned Bragg fibers with a large tuning range. With the development of the wavelength division multiplexed-passive optical network system for broadband, network security, and high-speed transmitted data capacity, fiber grating has become an indispensable device in high-performance optical communications systems due to its unique features such as wavelength selectivity, high tunabilty, and low-loss characteristics. The main technique to create Bragg gratings is through interaction with other light. By creating an interference pattern with prisms, mirrors, or a phase mask, this pattern can be written in the optical fiber. But there is one condition: The optical fiber needs to be photosensitive.
