An integrated wavelength selective coupler based on long period grating written in twin-core fiber

摘要

Wavelength selective couplers (WSC) are demonstrated theoretically and experimentally by writing long period gratings (LPGs) in a twin-core fiber (TCF). The coupling characteristics of the wavelength selective coupler are analyzed for different conditions based on the coupled-mode theory. Two LPGs with nearly the same resonant wavelength are written in each core of the TCF by using a high frequency CO2 laser. The experimental results show that the LPGs in the TCF can couple the light from one core to the other and a peak coupling efficiency of 42% has been achieved. Our results prove the viability of realizing an integrated wavelength selective coupler by using the configuration of TCF with LPFs.