基于多模干涉耦合器的集成热光开关实验研究

报道了一种基于多模干涉(MMI)耦合器的马赫曾德尔干涉仪(MZI)型2×2集成热光开关的实验研究结果,插损为3.40 dB,偏振相关损耗为0.47 dB,直通和交叉状态消光比分别为32.01 dB和16.42 dB,响应时间小于3 ms,开关功耗为658 mW。针对直通和交叉状态消光比不对称的现象,从理论上做出了解释,因为半导体平面光波电路(PLC)工艺一致性较好,两个多模干涉耦合器的分光比虽然因工艺误差偏离50∶50,但误差量相近,这个特点对光开关直通和交叉状态的消光比产生了不同影响。分析了在波导上制作加热电极对波导有效折射率的影响,估算其增量在2×10-4量级。

Experimental Research on Integrated Thermooptic Switch Based on Multimode Interference Couplers

The experimental results of a 2×2 integrated thermooptic Mach-Zehnder interferometer (MZI) switch based on multimode interference (MMI) couplers are reported. The insertion loss is 3.40 dB, polarization-dependent loss is 0.47 dB, extinction ratios at bar state and cross state are 32.01 dB and 16.42 dB respectively, response time is less than 3 ms, and power consumption is 658 mW. Regarding to asymmetry of extinction ratios at bar state and cross state, theoretical analysis is presented. Coupling ratio of the two multimode interference couplers deviates from 50:50, but the deviation is nearly the same, which is decided by good uniformity of semiconductor planar lightwave circuit (PLC) process. This property affects extinction ratios at bar state and cross state in different mechanisms. Adding metal heating electrode on waveguide affects its effective index and analysis based on experimental results is given. The increment of waveguide effective index is in the order of 2×10-4.