Polymer 1 X 2 couplers were fabricated using multimode optical waveguide circuit tech-niques which are amenable to low-cost production strategies. Optical circuit design and basic materials were selected to enable the couplers to be compatible with 250 μm diameter Eska-10(R) plastic fiber. The "all polymer" coupler, with input and output plastic fiber pigtails, had an excess loss of less than 2 dB and a loss uniformity of 0.8 dB at 820 nm. Variations in excess loss were 1 dB over a wavelength range from 420 to 850 nm. Directivity values of 25 ± 5 dB were measured and coupler performance was found to be only minimally affected by temperature over the range of 0 to 70°C.
Anthony A. Boiarski,
"Low-Cost 1 X 2 Fiber Optic Coupler Using Plastic Fiber", Proc. SPIE 0840, Fiber Optic Systems for Mobile Platforms, (3 December 1987); doi: 10.1117/12.942589; https://doi.org/10.1117/12.942589