Low Loss $1×2$ Optical Coupler Based on Cosine S‐bend with Segmented Waveguides Available to Purchase

This paper presents an optimization of $1×2$ polymer Y‐junction optical coupler. The optimized optical coupler comprises straight polymer waveguide as the input waveguide, tapered waveguide, modified cosine S‐bend and linear waveguide. At the branching point, N short waveguides with small width are introduced to reduce evanescent field. At operating wavelength of 1550 nm the excess loss of the coupler is ∼0.18 dB. In term of polarization dependence loss (PDL), the proposed coupler also shows a good performance with PDL value of less than 0.015 dB for wavelength range of 1470 nm–1550 nm. The proposed coupler could reduce excess loss more than 25% compared to conventional Y junction optical coupler.