Compact low-loss optical 72° hybrid based on nonoverlapping-image multimode interference coupler in silicon-on-insulator

Ze-Zheng Li, Yingxin Kuang, Huan Guan, Yang Liu, Xinqun Zhang, Weihua Han, Zhi-Yong Li
2019 IEEE Photonics Journal  
A universal principle to achieve different optical hybrids is summarized based on general nonoverlapping-image MMI couplers. An optical 72 • hybrid is proposed and demonstrated which is achieved by a 2 × 5 multimode interference (MMI) coupler with length of 89.5 μm and width of 8.0 μm. The device is fabricated in silicon-on-insulator (SOI) with 220 nm thick top silicon layer and the buried oxide layer is 3 μm thick. The proposed device exhibits an extinction ratio larger than 20 dB from 1470.8
more » ... 20 dB from 1470.8 nm to 1581.2 nm. The excess loss of optical hybrid is about 1.4 dB and a phase deviation less than ±6.0 • is obtained with the bandwidth of 51.5 nm.
doi:10.1109/jphot.2019.2956260 fatcat:ixgklaru25fzdcfcj5kmncwkmy