Modeling and measurement of losses in silicon-on-insulator resonators and bends.
We present an analytical model to quantify losses in resonators and bends without uncertain contributions from fiber coupling in/out or waveguide cleavage facets. With resonators in add-drop configuration, intrinsic losses are calculated from the free spectral range, through-port extinction and drop-port bandwidth. We fabricated and characterized silicon-on-insulator resonator for loss analysis. At 1.55 mum, racetrack resonators with a bending radius of 4.5 mum show intrinsic losses as small as 0.14+/-0.014 dB/round-trip. Meanwhile, intrinsic losses increase up to 1.23 dB/round-trip in the racetrack resonator that has a bending radius of 2.25 mum. Losses in a 180 degrees bend are estimated as a half of the intrinsic losses in these racetrack resonators, i.e., 0.07+/-0.007 dB/turn for a bending radius of 4.5 mum and 0.62 dB/turn for a bending radius of 2.25 mum. Loss in a 90 degrees bend with a radius of 4.5 mum is determined to be 0.06+/-0.006 dB/turn at 1.55 mum. The losses in 180 degrees or 90 degrees bends are found to be mainly due to the transition loss between waveguide bends and straight waveguides.
Xiao
Shijun
S
Khan
Maroof H
MH
Shen
Hao
H
Qi
Minghao
M