Linearly chirped microwave waveforms (LCMWs) are indispensable in advanced radar systems. Our study introduces and validates, through extensive experimentation, the innovative application of a thin-film lithium niobate (TFLN) photonic integrated circuit (PIC) to realize a Fourier domain mode-locked optoelectronic oscillator (FDML OEO) for generating high-precision LCMW signals. This integrated chip combines a phase modulator (PM) and an electrically tuned notch micro-ring resonator (MRR), which functions as a rapidly tunable bandpass filter, facilitating the essential phase-to-intensity modulation (PM-IM) conversion for OEO oscillation. By synchronizing the modulation period of the applied driving voltage to the MRR with the OEO loop delay, we achieve Fourier domain mode-locking, producing LCMW signals with an impressive tunable center frequency range of 18.55 GHz to 23.59 GHz, an adjustable sweep bandwidth from 3.85 GHz to 8.5 GHz, and a remarkable chirp rate up to 3.22 GHz/μs. Unlike conventional PM-IM based FDML OEOs, our device obviates the need for expensive tunable lasers or microwave sources, positioning it as a practical solution for generating high-frequency LCMW signals with extended sweep bandwidth and high chirp rates, all within a compact and cost-efficient form factor.

On-demand and real-time generation of arbitrary complex fields directly from the laser source holds significant appeal for myriad applications. In this Letter, we demonstrate a ring laser configuration capable of dynamically generating arbitrary transverse fields. In a ring laser resonator, two cascaded phase modulations are utilized, which permits the control of two beams with high efficiency and high fidelity. The zeroth-order beam is a fundamental Gaussian field that self-reproduces itself in the resonator. The first-order beam serves as the desired output field, which is separated from the self-reproduction mode to facilitate the on-demand manipulation of amplitude and phase. In the verification experiments, a series of typical Hermite–Gaussian (HG) modes, Laguerre–Gaussian (LG) modes, flat-top mode, and amplitude-only pattern “A” are generated from the ring laser configuration. This innovative ring laser resonator may open up new perspectives for the design of structured-light lasers, with potential impacts in applications such as particle manipulation, advanced microscopy, and next-generation optical communication.