LiDAR has attracted increasing attention because of its strong anti-interference ability and high resolution. Traditional LiDAR systems rely on discrete components and face the challenges of high cost, large volume, and complex construction. Photonic integration technology can solve these problems and achieve high integration, compact dimension, and low-cost on-chip LiDAR solutions. A solid-state frequency-modulated continuous-wave LiDAR based on a silicon photonic chip is proposed and demonstrated. Two sets of optical phased array antennas are integrated on an optical chip to form a transmitter–receiver interleaved coaxial all-solid-state coherent optical system which provides high power efficiency, in principle, compared with a coaxial optical system using a 2 × 2 beam splitter. The solid-state scanning on the chip is realized by optical phased array without a mechanical structure. A 32-channel transmitter–receiver interleaved coaxial all-solid-state FMCW LiDAR chip design is demonstrated. The measured beam width is 0.4° × 0.8°, and the grating lobe suppression ratio is 6 dB. Preliminary FMCW ranging of multiple targets scanned by OPA was performed. The photonic integrated chip is fabricated on a CMOS-compatible silicon photonics platform, providing a steady path to the commercialization of low-cost on-chip solid-state FMCW LiDAR.

We demonstrate a single-mode hybrid integrated laser architecture combining a waveguide Bragg grating fabricated on a 3 µm silicon-on-insulator (SOI) platform with a semiconductor optical amplifier (SOA) gain chip. Utilizing a Bragg grating with a controlled period of 224 nm, and duty cycle of 75%, the device achieves a narrow intrinsic linewidth of 4.89 kHz. With a compact 6-mm-long DBR grating, this design simultaneously yields an ultra-sharp spectral filtering with the full width at half maximum value of 30 pm and a low coupling constant of 0.68 cm⁻¹. Leveraging the thick-SOI platform's advantages-including superior fiber-chip coupling efficiency and enhanced power handling capabilities - in conjunction with a high-power SOA design, the system delivers output power of 112 mW while maintaining kHz-level linewidth. This performance-optimized design establishes a manufacturable pathway for implementing high-power narrow-linewidth lasers in coherent optical networks, optical atomic clocks, and light detection and ranging (LiDAR) systems that require simultaneous high coherence and high-power output.

This study demonstrates the implementation of high-order hole gratings within a silicon planar waveguide platform. Through optimization of the structural parameters, we achieve narrow-band operation with full width at half maximum (FWHM) values ranging from 70 pm to 130 pm, and coupling constants ( $\kappa $ ) in the range of 0.58 cm¹ to 1.06 cm¹. These results facilitate the development of long-cavity single-mode lasers with kHz-level linewidths, all within a compact monolithic platform.

A compact and low-loss multimode waveguide bend plays a significant role in multimode channels and high-density on-chip optical interconnection architectures, and it has become a key component of photonic integrated chips. Here, we propose an inverse design method based on staged optimization of high-order Bezier curves with high degrees of freedom, which effectively overcomes the optimization limitations of traditional geometric curve design. Using this approach, we demonstrate an ultra-compact 90° multimode waveguide bend on a 220 nm silicon-on-insulator (SOI) platform, featuring an effective bending radius as small as 9 μm and supporting four TE modes. Furthermore, the bend is extended to arbitrary angle interconnects, with 60°, 120°, and 180° configurations as examples, significantly enhancing the flexibility and adaptability of on-chip compact multimode interconnections. Simulation results show that 90° bend exhibits excellent performance at 1550 nm with excess losses below 0.038 dB and crosstalk below −30 dB . The proposed design was further fabricated and experimentally characterized. The maximum measured excess loss is 0.13 dB, and the inter-mode crosstalk is all below −25 dB at 1550 nm. This device combines ultra-compact footprint, low loss, and excellent scalability, suitable for high-density on-chip interconnects.

In this paper, we propose a compact 180° adiabatic tapered waveguide bend based on a higher-order Bézier curve. By co-optimizing the inner and outer boundaries of the Bézier profile, the design achieves simultaneous high-efficiency adiabatic transmission and 180° optical path reversal between narrow and broadened waveguides. Fabricated on a 400 nm silicon nitride platform, the proposed bend features a small bending radius of 20 μm, achieves a waveguide width variation from 0.8 μm to 2.5 μm, and exhibits an insertion loss below 0.01 dB across the 1290–1330 nm wavelength range. This compact, broadband, and fabrication-tolerant 180° bend provides a vital building block for high-density, low-loss photonic integrated systems.