Efficient Optical Coupling to Ultra-Low Mode Area Silicon V-Groove Waveguides

We investigate the coupling performance between conventional silicon strip (A
eff
∼ 0.06 μm
²
) and novel ultra-low mode area V-groove waveguides (A
eff
∼ 0.005 μm
²
) in a directional coupler configuration. We find high peak coupling efficiencies and examine fabrication tolerances and operating bandwidth.