Polarization-resolved control and measurement of the optical field are essential for a wide range of photonic systems, including coherent communication, polarimetric sensing, and quantum information processing. We present a photonic integrated circuit that enables the generation and analysis of arbitrary polarization states. The device provides reconfigurable access to the full polarization degree of freedom of coherent light within a single integrated platform. We experimentally demonstrate arbitrary polarization state generation spanning the Poincare sphere, as well as Stokes vector measurement on chip. Unlike conventional Stokes measurements that rely on direct detection, polarization analysis utilizing this architecture is intrinsically non-destructive, preserving the optical signal for further optical domain processing. The devices are fabricated in a commercial foundry using CMOS-compatible processes, enabling scalable and reproducible integration. By combining polarization generation and analysis in a compact and stable photonic circuit, this work eliminates the need for external polarization optics and provides a foundation for robust, polarization-enabled photonic integrated systems.
Polarization is a fundamental degree of freedom of light and plays a central role in a wide range of optical systems, from classical and quantum communications [1][2][3] to sensing [4], imaging [5][6][7], and metrology [8]. The ability to generate, manipulate, and analyze arbitrary polarization states enables advanced functionalities such as polarization-division multiplexing, polarization-resolved coherent detection, ellipsometry, and polarimetric imaging. As photonic systems continue to scale in complexity and performance, precise and reconfigurable control over polarization has become increasingly important.
An integrated platform that can both generate and analyze arbitrary polarization states enables a self-contained polarimetric system, eliminating the need for external optics and simplifying system-level integration. Such capability is particularly attractive for applications requiring real-time polarization tracking, adaptive compensation, or compact instrumentation, including coherent transceivers, polarization-sensitive sensors, and onchip quantum photonic circuits. By bringing polarization control and measurement onto a single chip, polarimetric photonic integrated circuits (PICs) open new opportunities for scalable and robust polarization-enabled photonic systems.
Several methods for integrated photonic polarization analyzers and generators have been investigated previously. In particular, metasurface-based analyzers that operate by spatially demultiplexing polarization components have shown great success [6,7,9,10]. However, these devices often act as components in a large bulk optics system. Fully integrated polarization analyzers on PIC platforms have also been demonstrated [11][12][13][14][15]; however, these devices operate solely with passive, fixed operation components and lack the reprogrammability required to operate as a polarization generator. Polarization sensitive measurements in beams have also been demonstrated using interferometer meshes fed by sets of grating couplers at different angles. While these systems are capable of performing arbitrary polarization analysis, their spatial resolution is ultimately limited by the array of gratings used as a coupling interface [16].
We have developed a compact integrated photonic architecture based on reprogrammable, bidirectional photonic meshes for generating and analyzing arbitrary polarization states. The architecture relies on two key components: a polarization splitting grating coupler (PSGC) [14,17,18] and a two-stage binary tree photonic mesh comprised of Mach-Zehnder Interferometers (MZIs) [19][20][21][22]. The PSGC we have designed is a symmetric, four-port device that performs two operations. It nominally acts as a polarizing beam splitter, spatially demultiplexing the horizontally and vertically polarized components of an input free space beam. Secondarily, the device acts as a polarization rotator, coupling both horizontally and vertically polarized light into the quasi-TE mode of their respective waveguide ports. Thus, the PSGC enables the decomposition of any free space beam into the fundamental quasi-TE mode at each of the device’s four ports. The relative complex amplitudes that describe each of the device’s four ports then fully characterize the input polarization state.
When operated as an analyzer, we employ a binary tree of MZIs, leveraging self-configuration algorithms [20,23,24] to recombine the outputs of the PSGC into a single output of the PIC. The phase shifter settings required to interferometrically recombine the outputs of the PSGC into a single output port of the PIC contain the information needed to determine the input polarization state. Unlike typical Stokes parameter measurement techniques, this method does not require the direct detection of the beam being analyzed, such that any input signal is preserved for further optical signal processing by spectroscopy [25,26], spatial mode analysis [27,28], or other coherent detection methods [29,30]. When operated as a polarization synthesizer, the binary tree of MZIs is used to generate arbitrary sets of complex amplitudes at the ports of the PSGC, resulting in programmatic control of the launched polarization state. In this work, we operate the device in both configurations, demonstrating the efficacy of this architecture for polarization analysis and generation.
The PSGC used in this work is designed by enforcing fourfold symmetry onto a typical uniform Bragg’s grating coupler. This device leverages the horizontal symmetry of a normalincidence beam centered on a two-dimensional square lattice grating coupler. This principle is shown in Fig. 1 (a) and (b), where a normal-incidence beam, which has a dominant field component that is out of plane (E y ), is centered on a horizontally symmetric grating. It can be observed that the beam is coupled equally into the fundamental quasi-TE mode at the two opposing ports of the device. In accordance with the horizonta
This content is AI-processed based on open access ArXiv data.