分光比可设计的偏振无关光功分器研究

Polarization-Independent Optical Power Splitter with a Designable Splitting Ratio

基于三明治结构和绝热耦合器,设计了一种分光比可设计的偏振无关光功分器,对波长为1550 nm的光信号实现所需分光比的功率分配。通过调节三明治结构中间层材料SiNx的折射率,使同一波长下横电(TE)和横磁(TM)偏振模的分光比相等,实现偏振无关,通过改变绝热耦合器波导间隙的不对称性,获得可设计的分光比。运用三维有限时域差分方法,对器件进行建模仿真,最终结果表明:所设计的器件耦合长度仅为7μm,可设计分光比的最大范围为0.50~0.95,同时支持TE和TM偏振模,插入损耗均低于0.31 dB,分光比容差在±0.01内的带宽可达100 nm,在未来光子集成光路系统中具有潜在的应用价值。

Based on a sandwich structure and adiabatic coupler,a polarization-independent optical power splitter with a designable splitting ratio is designed to achieve power distribution for the 1550 nm wavelength optical signal with a designable splitting ratio.By adjusting the refractive index of the sandwiched middle layer material SiNx,the splitting ratios of the transverse electric(TE)and transverse magnetic(TM)polarization modes are made equal at the same wavelength,and a polarization-independence function is realized.Next,the designable splitting ratio function is obtained by varying the asymmetry of the waveguide gaps in the adiabatic coupler.The three-dimensional finite-difference timedomain method is used for modeling and simulations.The results reveal that the coupling length of the proposed device is only 7μm.The device can achieve designable splitting ratios ranging from 0.50 to 0.95 and simultaneously support the TE and TM polarization modes.The insertion loss value is lower than 0.31 dB.A 100 nm bandwidth can be obtained when the tolerance of the splitting ratio is within±0.01.The proposed approach is potentially applicable to future photonic integrated circuit systems.