Analytical prediction of coupling losses in bend silicon subwavelength optical interconnect

Abstract

For the first time, singular perturbation technique in conjunction with effective index method is used to quantitatively estimate parametric variations in a bend rectangular waveguide of subwavelength dimensions that forms a basic unit of photonics integrated circuits optical interconnect. These parametric variations are correlated to losses due to bending and coupling of bend and straight waveguides. The results are compared with that obtained by more rigorous finite elements method. A scheme to compensate the losses is also proposed. In case of tight bends (bending radius ≈ 10 μm) coupling loss compensation of about 40 dB is achieved.