Goswami Arnab, Krishna Das Bijoy
Opt Lett. 2022 Mar 15;47(6):1474-1477. doi: 10.1364/OL.453518.
Photon pair generation via spontaneous four-wave mixing in silicon waveguides/microring resonators integrated with a high extinction pump rejection filter is very much in demand for futuristic large-scale integrated quantum photonics circuits. Ideally, a distributed Bragg reflector (DBR) can be designed to offer desired pump rejection. However, fabricated DBRs suffer degradation in pump extinction due to roughness-induced unwanted scattering waves in the forward direction around the Bragg wavelength. It is therefore inferred that the roughness-induced forward scattering can be reduced significantly by integrating a DBR structure in one of the sidewalls (instead of two sidewalls) of a multimode rib waveguide (instead of a single mode strip waveguide). Therefore, we studied a single-stage DBR filter with this design which exhibits a significantly higher stop band extinction (∼63 dB), in comparison with that of earlier reported results (<50 dB). To validate the pump rejection efficiency of such fabricated devices in quantum photonic applications, we have carried out on-chip stimulated four-wave mixing experiments and shown that the pump laser within the rejection band could be attenuated to the level of idler power.
通过与高消光泵浦抑制滤波器集成的硅波导/微环谐振器中的自发四波混频产生光子对，对于未来的大规模集成量子光子学电路来说需求非常大。理想情况下，可以设计一个分布式布拉格反射器（DBR）来实现所需的泵浦抑制。然而，由于在布拉格波长附近的前向方向上粗糙度引起的不需要的散射波，制造的DBR在泵浦消光方面会出现退化。因此可以推断，通过在多模脊形波导（而不是单模条形波导）的一个侧壁（而不是两个侧壁）中集成DBR结构，可以显著降低粗糙度引起的前向散射。因此，我们研究了采用这种设计的单级DBR滤波器，与早期报道的结果（<50 dB）相比，它表现出明显更高的阻带消光（约63 dB）。为了验证这种制造的器件在量子光子应用中的泵浦抑制效率，我们进行了片上受激四波混频实验，并表明阻带内的泵浦激光可以衰减到闲频功率水平。
