A CMOS Optoelectronic Transceiver with Concurrent Automatic Power Control for Short-Range LiDAR Sensors

Area of Science:

• Optoelectronics
• Integrated Circuits
• Sensor Technology

Background:

• Short-range LiDAR sensors require efficient optoelectronic transceivers (OTRx).
• Conventional OTRx designs face challenges with varying laser diode characteristics, impacting performance.
• Complementary metal-oxide-semiconductor (CMOS) technology offers a cost-effective platform for integrated sensor solutions.

Purpose of the Study:

• To present a novel optoelectronic transceiver (OTRx) optimized for short-range LiDAR applications.
• To integrate a modified current-mode single-ended VCSEL driver (m-CMVD) transmitter (Tx) and a voltage-mode fully differential transimpedance amplifier (FD-TIA) receiver (Rx).
• To implement a concurrent automatic power control (APC) circuit for stable operation.

Main Methods:

• Realization of the OTRx in a 180 nm CMOS technology.
• Utilization of a modified current-mode single-ended VCSEL driver (m-CMVD) for the transmitter.
• Integration of two spatially modulated P+/N- well avalanche photodiodes (APDs) with the FD-TIA receiver and an additional APD for APC.
• Development of a novel APC path within the receiver to adjust the VCSEL driver's bias current.

Main Results:

• The proposed OTRx demonstrates stable operation across a wide input current range.
• DC bias current increased from 0.93 mA to 1.42 mA as input current decreased from 250 µA_pp to 3 µA_pp.
• The integrated APC circuit effectively compensates for threshold current variations in the VCSEL diode.

Conclusions:

• The developed OTRx is suitable for short-range LiDAR sensor applications.
• The cost-effective CMOS implementation makes the design attractive for mass production.
• The integrated APC mechanism ensures reliable performance and compensates for VCSEL diode variations.