Shanghai Jiao Tong University

Liangjun Lu

Jianping Chen

Jiao Liu

Linjie Zhou

Weihan Xu

Wensheng Shan

Junjie Du

Chen Zhu

A calibration system and related methods for optical phased array chips. The calibration system includes an adjustable mount module, an infrared microscopic observation module, an arrayed driver module, a two-dimensional laser beam scanning module, a photoelectric conversion module and an upper computer, and utilizes computer-vision-enabled positioning and phase error compensation algorithms as software components. Collimated laser is emitted from the target beamforming angle and aimed at the emission aperture of the chip, and is subsequently sampled by the array elements in a reversed injection manner. Based on the reciprocity of light propagation, by maximizing the power reversely output from the bus waveguide of the optical phased array chip, beamforming at the target angle is achieved supported by software implementations of optimization algorithms. The system and related methods are readily achievable, highly automated, and offers fast and batch calibration with relatively low expenses, good flexibility and long-term compatibility.

Calibration system and method for integrated optical phased array chip

A chip-scale silicon-based hybrid-integrated LiDAR system, wherein a transmitting end thereof sequentially comprises a narrow-linewidth tunable laser source, a silicon-nitride-based beam splitter, a silicon-based phase shifter array and a silicon-nitride-based unidirectional transmitting antenna array w.r.t the optical path. Based on the principle of reciprocity of light propagation, the receiving end thereof sequentially comprises a silicon nitride unidirectional receiving antenna array, a silicon nitride beam splitter and a silicon-based coherent receiving module. It also comprises a backup system and an electric controller as the driver of the phase shifters and the processing module. Modules on the silicon platform and the silicon nitride platform are monolithic integrated in a multilayer sandwiched fashion by means of a tapered silicon/silicon nitride evanescent inter-layer coupler; and a gain chip in the tunable laser module and a silicon nitride waveguide are hybrid-integrated by horizontal coupling.

Chip-scale silicon-based hybrid-integrated LiDAR system

A three-dimensional scanning LiDAR based on one-dimensional optical phased arrays comprises a transmitting end, a coherent receiving end and an incoherent receiving end, wherein the transmitting end, the coherent receiving end and the incoherent receiving end are all one-dimensional arrays. A phase control complexity of the three-dimensional scanning phased array is reduced, and a tunable laser with high cost and a grating array antenna with large crosstalk are avoided. The LiDAR provides pure solid-state three-dimensional scanning in speed and integration level and is highly practical.

Three-dimensional scanning LiDAR based on one-dimensional optical phased arrays

Integrated two-dimensional multi-beam LiDAR transmitter based on the Butler matrix, comprising an tunable laser array, a frequency modulated continuous wave modulator array, an N×N Butler optical matrix network, an N×M optical beam expanding network, an M-path phase shifter array, and an M-path two-dimensional LiDAR emitters. N-path narrow linewidth continuous light output by the tunable laser array passes through the frequency modulated continuous wave modulator array to generate N-path frequency modulated continuous light signals; after processed by the N×N Butler matrix and the N×M optical beam expanding network, energy of each path of the frequency modulated continuous optical signal is evenly distributed to the M-path output ports, and the M-path phase shifter array generates equal-difference phases with continuously tunable phase differences for M-path optical signals, which, with continuously tunable phase differences, are transmitted by M-path two-dimensional LiDAR emitters to realize no more than N different two-dimensional steerable transmitting optical beams.

Integrated two-dimensional multi-beam lidar transmitter based on butler matrix

A silicon Fourier transform spectrometer and an optical spectrum reconstruction method are disclosed. The spectrometer includes a waveguide input coupler, cascaded optical switches, unbalanced subwavelength grating (SWG) waveguide pairs, and a germanium silicon detector, where the cascaded optical switches are connected through unbalanced SWG waveguide pairs. The state of the optical switches are adjusted to digitally configure the optical path, so as to constitute a series of unbalanced Mach-Zehnder interferometer (MZI) arrays with different optical path differences, to realize a Fourier transform spectrometer based on spatial heterodyne. The optical spectrum is reconstructed by using a compressed sensing algorithm.

Silicon fourier transform spectrometer and optical spectrum reconstruction method

A silicon- and optical phased array-based integrated optically adjustable delay line, comprising, an optical phased array transmitting unit, a slab waveguide transmitting unit, and an optical phased array receiving unit that are sequentially arranged. By the optical phase control transmitting unit, the phase difference between channels is regulated and controlled via a phase shifter to change a far-field interference light spot and form a wave beam with directivity to regulate and control an incident angle of an optical signal entering the slab waveguide, thus changing the propagation path length of the optical signal. Finally, the optical signal is received by a corresponding optical phased array receiving unit to obtain different delay amounts. Large adjustable delay amount is realized and the delay line has the advantages of simple structure and control and high integration level with high application value in optical communication and microwave photonic and optical signal processing.

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Shanghai, China

Liangjun Lu