On-chip high-speed coherent optical signal receiver based on photonic spin-Hall effect

Abstract

The use of coherent optical signal processing in long-distance optical communication systems has dramatically increased data capacity enabling encoding of multiple-bit information in the amplitude and phase of a light beam. Direct detection of phase information of a high-speed modulated light remains challenging and requires an external, local oscillator for referencing, which is expensive for short-reach optical communications, for example, in datacenters. The availability of less complex integrated photonics devices for coherent signal detection would alleviate this bottleneck. On the other hand, phase information of coherent, orthogonally polarized light beams can be extracted from their polarization states and it is, therefore, possible to achieve phase measurements via fast polarization detection. Here we demonstrate an on-chip, high-speed coherent optical signal receiver enabled by spin-orbit coupling in Si-photonics circuitry. In a coherent communication experiment with up to 16 Gbaud/s rate, the high-speed quadrature phase-shift keying signals detected by a Si nanodisk based polarisation measurements at multiple wavelength in the C-band were recovered with a bit error rate below the forward error correction threshold. The proposed on-chip nanodisk coherent receiver shows promise in high-speed coherent optical communication applications where phase detection is required at low cost and small footprint.

Symmetry‐Protected Photonic Chiral Spin Textures by Spin–Orbit Coupling

“…Even for the SPP configuration, the loss mechanism does not affect the symmetry of the optical system, and it can be ignored by only considering the probability distribution of a single EM wave packet at the interface. [ 52,53 ] Moreover, from the former experimental results related to the photonic chiral textures, [ 11,12,17,18,31,45–48 ] one can find that the material loss primarily influences the intensity (photon number) but not the orientation of the vector. Thus, we can ignore material losses for convenience.…”

“…[2][3][4][5] In addition, owing to the "intrinsic" spinorbit coupling governed by Maxwell's theory, many topology-like phenomena have been reported in real space, including polarization Möbius strips [6,7] and polarization vortices, [8,9] along with various chiral textures, such as optical domain walls, [10] photonic skyrmions, and merons. [11][12][13][14][15][16][17][18][19] Among these chiral textures, the magnetic skyrmion, [20][21][22] which was named after nuclear physicist Tony Skyrme, is a topologically nontrivial spin that forms via the spin-orbit interaction (Dzyaloshinskii-Moriya interaction: DMI) in an electronic system that lacks inversion symmetry and minimizes the magnetic energy cost. The recently discovered photonic skyrmions, which have chiral spin textures and can be considered as the optical manifestation of magnetic skyrmions, have attracted widespread interest in the fields of spin optics, chiral quantum optics, and photoelectric interaction.…”