Micro-electronic integration enables the ubiquitous deployment of devices in large volumes, from robotics to autonomous vehicles and photonic transceivers. This thesis applies these principles to short-wave infrared (SWIR) LiDAR, advancing optoelectronic integration for both direct time-of-flight (dToF) and coherent sensing architectures by demonstrating novel integrated circuit designs.

For dToF sensing, a room-temperature 3D-stacked flash LiDAR sensor is presented for the SWIR regime. The 96$\times$96 InGaAs/InP single-photon avalanche diode (SPAD) array in the top tier is biased by a bottom-tier readout integrated circuit (ROIC) that implements a novel complementary cascoded gating architecture. This circuit is specifically tailored to control the noise and afterpulsing characteristic of InGaAs SPADs. Fabricated in a 110-nm CMOS technology, the proposed sensor successfully demonstrates intensity imaging and depth mapping in both indoor and outdoor environments.

To further scale these systems, larger-format ROIC architectures are introduced, featuring advanced methods to improve the signal-to-noise ratio and data throughput of dToF sensors. Specifically, a 288$\times$64 pixel 3D-stacked InGaAs/InP SPAD array is presented. The 110-nm CMOS readout architecture incorporates per-pixel gating with binary memory and a novel hardware-level coincidence processing scheme. Initial experimental results demonstrate robust room-temperature array functionality, including breakdown voltage mapping and SWIR intensity imaging. This architecture provides scalable, low-complexity noise reduction for large-format InGaAs SPAD arrays, marking a significant step toward practical SWIR single-photon LiDAR sensors.

Beyond dToF sensing, chip-scale integration is critical for coherent laser ranging (FMCW LiDAR), which offers instantaneous velocity and distance detection, eye-safe operation, and interference immunity. While integrated silicon photonics-based beam-forming has advanced rapidly, full wafer-scale integration remains hindered by stringent laser requirementsâ namely, high optical coherence, drivers enabling low chirp nonlinearity, and optical amplification.

To address these challenges, we propose a custom high-voltage arbitrary waveform generator (HV-AWG) utilizing a novel circuit architecture based on a voltage-controlled oscillator and a charge pump. This design generates high-voltage time-domain waveforms entirely within standard CMOS technology. By eliminating the need for dedicated high-voltage foundry processes, the driver can be seamlessly co-integrated with the advanced digital signal processing nodes inherent to modern LiDAR systems.

Leveraging this driver, we demonstrate a fully photonic-electronic integrated coherent LiDAR engine fabricated via foundry-compatible wafer-scale manufacturing. The complete system comprises the micro-electronic HV-AWG, a hybrid photonic tunable Vernier laser with piezoelectric actuators, and an erbium-doped waveguide optical amplifierâ successfully merging III-V semiconductors, \SiN{} photonic integrated circuits, and a 130-nm SiGe BiCMOS technology. The resulting optical source is turnkey, linearization-free, and functions as a universal ``drop-in'' solution that seamlessly interfaces with existing focal plane and optical phased array architectures, constituting a critical milestone toward fully chip-scale integrated LiDAR systems.