Fabrication of long-period gratings in poly(methyl methacrylate-co-methyl vinyl ketone-co-benzyl methacrylate)-core polymer optical fiber by use of a mercury lamp

Polymer optical fiber (POF) with a highly photosensitive poly(methyl methacrylate-co-methyl vinyl ketone-co-benzyl methacrylate) core is fabricated. Gratings can be fabricated in the core of a POF with a low-cost mercury lamp. The part of the emission spectrum of the mercury lamp in which the cladding material exhibits photosensitivity is effectively filtered by a 1.5-mm-thick Pyrex glass to ensure that a long-period grating is formed only in the core of a POF. A long-period grating with a 3-dB resonant peak at 1568 nm is fabricated with 0.3 mW/cm2 of UV irradiation over a period of 200 s.