Novel Fabrication of Fiber Bragg Gratings Using Silicone Rubber Phase-Mask Stamp on the Cladding

Strong fiber Bragg gratings (FBGs) (17 dB) have been fabricated using a silicone rubber [polydimethylsiloxane (PDMS)] phase mask directly integrated on top of the cladding of an optical fiber. To achieve this result, a new technique was developed that took advantage of alterations of the material under low power exposure to a UV laser beam. Thus, the UV-improved PDMS phase masks were the key to achieve strong FBG inscription. Fluor plasma surface treatment of PDMS and variable depth profiles enables self-replication for the fabrication of chirped and complex FBG filters. Since the mask is fixed to the fiber, it can be reexposed at different times to increase its isolation and length or reduce the phase stitch between two gratings for precise tuning after use in a device. This technique enables new reconfigurable FBG or FBG tuning after/during use.