Photonic Integrated Circuit for Rapidly Tunable Orbital Angular Momentum Generation Using Sb₂Se₃ Ultra‐Low‐Loss Phase Change Material

Abstract

The generation of rapidly tunable optical vortex (OV) beams is one of the most demanding research areas of the present era as they possess orbital angular momentum (OAM) with additional degrees of freedom that can be exploited to enhance signal‐carrying capacity by using mode division multiplexing and information encoding in optical communication. Particularly, rapidly tunable OAM devices at a fixed wavelength in the telecom band stir extensive interest among researchers for both classical and quantum applications. This article demonstrates the realistic design of a Si‐integrated photonic device for rapidly tunable OAM wave generation at a 1550‐nm wavelength by using an ultra‐low‐loss phase change material (PCM) embedded with a Si‐ring resonator with angular gratings. Different OAM modes are achieved by tuning the effective refractive index using rapid electrical switching of Sb2Se3 film from amorphous to crystalline states and vice versa. The generation of OAM waves relies on a traveling wave modulation of the refractive index of the micro‐ring, which breaks the degeneracy of oppositely oriented whispering gallery modes. The proposed device is capable of producing rapidly tunable OV beams, carrying different OAM modes by using electrically controllable switching of ultra‐low‐loss PCM Sb2Se3.

On-chip programmable optical routing using nonvolatile Sb2Se3 phase-change metasurfaces

“…The crystallization and amorphization temperatures of Sb 2 Se 3 are 200ºC and 620ºC, respectively, which are comparable to those of GST (T crys = 140ºC and T amorph = 550ºC) [5]. These characteristics make Sb 2 Se 3 an ideal PCM for programmable photonics in the telecommunication band [1][2][4][5][6][7][8][9][10][11][12][13][14][15].…”

Generation of Photon Orbital Angular Momentum and Its Application in Space Division Multiplexing

“…Table 2 Still in the spatial domain, generating OAM beams at the nanoscale is of significant interest for various applications in nanophotonics [95,96] and optical device miniaturization [97]. Recent developments in the creation and detection of optical vortex as well as some of its applications are observed in photonic integrated circuits [98][99][100][101][102][103], micro-ring resonators [104][105][106][107][108][109][110][111], metamaterials [112][113][114][115][116][117][118][119][120], plasmonic nanostructures [121][122][123][124], and metasurfaces [125][126][127][128], which offer precise control over the phase, amplitude, and polarization of light at the nanoscale. By engineering the meta-atoms on a metasurface, it is possible to design them to introduce a tailored phase gradient, resulting in the generation of OAM beams.…”

Tunable fast optical filter using metamaterials and phase change material

“…Integration of PCMs into multilayer metamaterial structures has initiated extensive innovation for applications such as rewritable optical data storage, metasurfaces, and optoelectronic devices. PCMs have been studied deeply due to their reversible phase change transition, high endurance, high switching speed, and data retention [1,2]. Germanium antimony-tellurium (GST) is a PCM that has amorphous and crystalline phases with distinct properties, is bistable and nonvolatile, and undergoes a reliable and reproducible phase transition in response to an optical or electrical stimulus.…”