Experimental investigation of a long-period grating based coupler for high-capacity transmission systems

Abstract

In this work, we developed and characterized a coupler based on long-period gratings (LPGs). The coupler consists of two single-mode fibers close to each other with similar LPGs inscribed, and it was optimized by adjusting the longitudinal distance between the LPGs. The optimized coupler was then integrated into a 400G coherent optical transmission system to evaluate its impact on the signals. There was no penalty imposed over the 400G signals at the coupling band. These results show that an LPG based coupler could be used in high-capacity coherent transmission systems for wavelength-selective coupling.