Zurita Roberto O, Wiederhecker Gustavo S, Mayer Alegre Thiago P
Opt Express. 2021 Jan 18;29(2):1736-1748. doi: 10.1364/OE.413770.
We propose a feasible waveguide design optimized for harnessing Stimulated Brillouin Scattering with long-lived phonons. The design consists of a fully suspended ridge waveguide surrounded by a 1D phononic crystal that mitigates losses to the substrate while providing the needed homogeneity for the build-up of the optomechanical interaction. The coupling factor of these structures was calculated to be G/Q = 0.54 (W m) for intramodal backward Brillouin scattering with its fundamental TE-like mode and G/Q = 4.5 (W m) for intramodal forward Brillouin scattering. The addition of the phononic crystal provides a 30 dB attenuation of the mechanical displacement after only five unitary cells, possibly leading to a regime where the acoustic losses are only limited by fabrication. As a result, the total Brillouin gain, which is proportional to the product of the coupling and acoustic quality factors, is nominally equal to the idealized fully suspended waveguide.
我们提出了一种可行的波导设计，该设计针对利用具有长寿命声子的受激布里渊散射进行了优化。该设计由一个完全悬浮的脊形波导组成，其周围环绕着一维声子晶体，该晶体可减少向衬底的损耗，同时为光机械相互作用的建立提供所需的均匀性。对于其基本类TE模式的模内反向布里渊散射，这些结构的耦合因子计算为G/Q = 0.54（W/m），对于模内正向布里渊散射，G/Q = 4.5（W/m）。声子晶体的加入在仅五个单元胞之后就提供了30 dB的机械位移衰减，这可能导致一种声学损耗仅受制造限制的情况。因此，与耦合和声学品质因数的乘积成正比的总布里渊增益名义上等于理想化的完全悬浮波导。
