Optical phased array with on-chip phase calibration

Abstract

Optical phased arrays (OPAs) with phase-monitoring and phase-control capabilities are necessary for robust and accurate beamforming applications. This paper demonstrates an on-chip integrated phase calibration system where compact phase interrogator structures and readout photodiodes are implemented within the OPA architecture. This enables phase-error correction for high-fidelity beam-steering with linear complexity calibration. A 32-channel OPA with 2.5-µm pitch is fabricated in an Si–SiN photonic stack. The readout is done with silicon photon-assisted tunneling detectors (PATDs) for sub-bandgap light detection with no-process change. After the model-based calibration procedure, the beam emitted by the OPA exhibits a sidelobe suppression ratio (SLSR) of −11 dB and a beam divergence of 0.97° × 0.58° at 1.55-µm input wavelength. Wavelength-dependent calibration and tuning are also performed, allowing full 2D beam steering and arbitrary pattern generation with a low complexity algorithm.

Demonstration of inherently low differential phase noise across C-band in InP integrated, amplifying optical phased arrays

“…The diagnostic data from the deployed chip would improve the accuracy of estimated performance in different cases and is expected to drive design cycle improvements for the next generation of chips. Further, the DPN measurement structure also enables OPA calibration [29]. The OPA chip is operated at 18 0 C (SOA performance was previously measured at this temperature [30] )and is pumped by an external laser with narrow linewidth (Keysight 81960A +14 dBm, 100 kHz).…”

High-power mode-programmable orbital angular momentum beam emitter with an internally sensed optical phased array

“…Generally, an OPA refers to a system that uses the laser array as the carrier to flexibly control the individual phase of optical elements [50,51] , which could manipulate the combined beam pattern in the far field. The OPA has attracted growing attention and is widely applied in a range of applications, such as lidar [50,52] , beam steering [51,53] , and optical communications [54,55] .…”

“…Generally, an OPA refers to a system that uses the laser array as the carrier to flexibly control the individual phase of optical elements [50,51] , which could manipulate the combined beam pattern in the far field. The OPA has attracted growing attention and is widely applied in a range of applications, such as lidar [50,52] , beam steering [51,53] , and optical communications [54,55] . Different from the on-chip OPA [50][51][52][53][54] , the OPA that is based on a coherent fiber laser array has a promising prospect for forming the high-power OAM beam emitter [36,[43][44][45] .…”

“…The OPA has attracted growing attention and is widely applied in a range of applications, such as lidar [50,52] , beam steering [51,53] , and optical communications [54,55] . Different from the on-chip OPA [50][51][52][53][54] , the OPA that is based on a coherent fiber laser array has a promising prospect for forming the high-power OAM beam emitter [36,[43][44][45] . In practice, to generate the OAM beam with an OPA, the piston phase of each element in the source plane is modulated to fit a whole helical phase structure [36,[43][44][45] .…”