Spin-orbit interaction of light in photonic nanowaveguides: A proposal of graphene-based optical isolators
Refereed conference paper presented and published in conference proceedings



摘要Light carries both spin and orbital momentum. It is found recently that the spin and orbital properties are strongly coupled with each other when light is tightly confined to subwavelength waveguiding structures. Here we exploit this spin-orbit interaction to propose an on-chip photonic isolator. Optical isolators are a type of nonreciprocal devices that allow for unidirectional light transmission by breaking the time-reversal symmetry. In traditional optics, such devices can easily be implemented by utilizing Faraday rotation effect of magneto-optical garnets. Recently, it has been found that a monolayer graphene also exhibits enormous magneto-optical effect which can be utilized to construct optical isolators. To date, most of graphene-based optical isolators take an out-of-plane scheme, where light propagates along the normal of the graphene sheet. Such scheme not only suffers from the short interaction length, but also is difficult for on-chip implementation where light propagates in a plane in parallel with the graphene sheet. Here, by utilizing the photonic spin-orbit coupling effect in nanowaveguides, we propose a hybrid graphene/silicon magneto-optical isolator for on-chip integration. Owing to the intrinsic transverse spin-momentum locking in photonic waveguides, the cyclotrons in graphene experience opposite photonic spin states for counterpropagating light. This results in different transmission spectra for the forward and backward propagating light. Our numerical simulation indicates that the proposed isolator can achieve excellent isolation performance with the extinction ratio as high as 45dB and the insertion loss less than 8dB at 1.552 μm by operating near a critical-coupling wavelength of a ring resonator. The excellent device performance, together with the advantage of CMOS compatibility, has shown its great promise as a new type of photonic nonreciprocal devices for on-chip integration.
著者Ma JW, Xi X, Yu ZJ, Sun XK
會議名稱2016 Progress in Electromagnetic Research Symposium (PIERS)
會議論文集題名2016 Progress in Electromagnetic Research Symposium (PIERS)
頁次980 - 980

上次更新時間 2021-10-01 於 02:00