Spin separation based on-chip optical polarimeter via inverse design

Abstract

Polarimetry has been demonstrated essential in various disciplines, such as optical communications, imaging, and astronomy. On-chip nanostructures for polarization measurements are most expected to replace the conventional bulk elements, and hence minimize the polarimeter for integrated applications. Some on-chip nanophotonic polarimeter via polarization detection has been implemented, in which the separation of two spin polarized states is needed. However, due to the relatively low coupling efficiency or complicated photonic silicon circuits, on-chip polarimetry using a single device still remains challenging. Here, we introduce and investigate an on-chip polarimeter with nanostructures using the inverse design method. The developed device shows the ability to detect the four polarization components of light, two of which are the spin polarizations, and the other two are the linear polarizations. The retrieved Stokes parameters with experimentally tested data are in close agreement with the numerical results. We also show the proof of concept demonstration for high-speed Stokes vector optical signals detection. In the high-speed communication experiment with data rate up to 16 GBd, the detected optical signals via polarization measurements at multiple wavelengths in the C-band were recovered with the bit error rate below the 20% forward error correction threshold. The proposed on-chip polarimeter shows promising performance both in Stokes polarimetry and high-speed optical communication applications.

Optimized optical catenary structures empower compact on-chip polarization detector

“…Over the past few years, metasurfaces have rapidly emerged as a fast developing research field due to their distinctive capabilities in optical manipulation. By adjusting the geometric parameters of nanostructures constituting the metasurfaces, manipulation of optical characteristics such as amplitude, phase, and polarization has been achieved [9][10][11][12][13][14] , leading to the realization plethora of ultrathin optical devices, including metalenses, holographic devices, and orbital angular momentum generators, etc [15][16][17][18][19][20][21][22] . Due to its inherent advantages of high sensitivity and high integration, polarization detectors based on metasurface designs have garnered widespread attention [23][24][25][26] .…”

On-Chip Integrated Metasystem with Inverse-Design Wavelength Demultiplexing for Augmented Reality

“…Distinct from traditional metasurfaces to operate with free-space light, − on-chip metasurfaces can manipulate guided waves and facilitate arbitrary interfacial conversion between the free-space light and the on-chip guided waves. Imparted the encoding-freedom from traditional metasurfaces, on-chip metasurfaces can enable engineering of light amplitudes, phases, and polarization states at the subwavelength scale and thus create various desired and practical functionalities including beam-steering, optical router, − lensing, − holographic display, − etc.…”