Optimization of device model for metal-based 1×2 Y-branch Plastic Optical Fiber coupler

A metal-based 1×2 Y-branch Plastic Optical Fiber (POF) coupler has been developed. The device is based on two metal-blocks sandwiched on each other where the device structure was engraved on one of the blocks. The developed device has a hollow waveguide taper region where light rays propagate solely by reflection on all of the metallic inner-surfaces of this region which are all reflective. Device modeling has been performed using two simple models. The first model performed with a complete hollow structure shows how the device works as an ideal 3 dB coupler. A second optimized model developed incorporates some real device parameters and physical limitations which include mismatch between the cylindrical-shaped POF fibers and the square-shaped waveguide core. In addition, an air gap between the top and bottom mold insert blocks is included to simulate the actual fabricated and assembled device. The assembled POF coupler has an insertion loss of 5.8 dB, excess loss of 2.8 dB and a good coupling ratio of 50∶50.