Patent ID: 8150228

Claim:
A device, comprising: a waveguide comprising a rib structure between a first waveguide channel and a second waveguide channel, the first waveguide channel comprising a first sidewall and a second sidewall, the first sidewall of the first waveguide channel comprising a sidewall of the rib structure, the second waveguide channel comprising a first sidewall and a second sidewall, the first sidewall of the second waveguide channel comprising a sidewall of the rib structure, the rib structure comprising a first end, a second end, a length extending in a first direction along the rib structure and a width extending in a direction that is substantially perpendicular to the length, light entering the rib structure at the first end propagates along the rib structure and exits the rib structure at the second end; at least one fin structure formed between the first sidewall and the second sidewall of the first waveguide channel that comprises a height that is substantially equal to a height of the first sidewall and the second sidewall of the first waveguide channel and a width that extends substantially in a same direction as the width of the rib structure; and a fin structure formed between the first sidewall and the second sidewall of the second waveguide channel that corresponds to each fin structure formed between the first sidewall and the second side wall of the first wave guide channel, the fin structure formed between the first sidewall and the second sidewall of the second waveguide channel comprising a width that extends substantially in a same direction as the width of the rib structure, the at least one fin structure in the first waveguide channel and the corresponding fin structure in the second waveguide channel together comprising an optical loss that is less than or equal to about 1.4 dB for a rib structure width that is less than or equal to about 1.80 μm and a fin structure width that is less than or equal to about 2.0 μm.