Poulton Christopher G, Pant Ravi, Byrnes Adam, Fan Shanhui, Steel M J, Eggleton Benjamin J
Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS), Australia.
Opt Express. 2012 Sep 10;20(19):21235-46. doi: 10.1364/OE.20.021235.
We propose a scheme for on-chip isolation in chalcogenide (As₂S₃) rib waveguides, in which Stimulated Brillouin Scattering is used to induce non-reciprocal mode conversion within a multi-moded waveguide. The design exploits the idea that a chalcogenide rib buried in a silica matrix acts as waveguide for both light and sound, and can also be designed to be multi-moded for both optical and acoustic waves. The enhanced opto-acoustic coupling allows significant isolation (> 20 dB) within a chip-scale (cm-long) device (< 10 cm). We also show that the bandwidth of this device can be dramatically increased by tuning the dispersion of the waveguide to match the group velocity between optical modes: we find that 20 dB isolation can be extended over a bandwidth of 25 nm.
我们提出了一种用于硫族化物（As₂S₃）肋形波导片上隔离的方案，其中受激布里渊散射用于在多模波导内诱导非互易模式转换。该设计利用了这样一个理念：埋在二氧化硅基质中的硫族化物肋条对光和声都起到波导的作用，并且还可以设计成对光波和声波都是多模的。增强的光声耦合使得在芯片级（厘米长）的器件（<10厘米）内实现显著的隔离（>20分贝）。我们还表明，通过调整波导的色散以匹配光学模式之间的群速度，可以显著增加该器件的带宽：我们发现20分贝的隔离可以扩展到25纳米的带宽上。
