LIDAR is a distance and speed measurement apparatus using reflection characteristics of an emitted light. A laser emits a brief coherent light pulse at a defined frequency. A photodetector measures the reflected light. The time between emitted and detected light allows to compute the distance from the target. Frequency shift in the reflected light also allows to measure the relative speed between the target and the LIDAR.
Societal applications for LIDAR are numerous. There is a strong interest in long range LIDAR for autonomous vehicle application. Space industry is also using LIDAR to scan planet surfaces before landing missions. LIDAR is also used to scan earth atmosphere from space or from ground. All these applications are requesting longer range for LIDAR. Current photodetectors used in LIDAR are reaching a theoretical limit requiring a major change in the photo detector choice.
Having the most sensitive detector is therefore a critical to measure long distances, particularly in space applications. Due to its very large gain, SiPM can detect single photon with a single photon timing resolution down to 30 ps RMS. As the first SiPM for LIDAR are getting on the market, no front-end electronics is proposed to read-out these SIPM arrays.
Resolution and sensitivity increase of LIDAR using SIPM will disrupt that technology. Existing systems can either be very sensitive by using photomultipliers – in that case, systems are single channel but can detect only few reflected photons – or high resolution using APDs matrices – in that case the multi-channel system has a high resolution but low gain of APD require a large number of photons, thus a lower distance range, to trig and perform measurement.
Future of LIDAR will involve multi-channel read-out of SiPM for which front-end ASIC will be mandatory. Increase of channel number using SiPM compared to photomultiplier tubes will allow a disruption in LIDAR resolution and sensitivity that can only be achieved by a dedicated microelectronics read-out chips fulfilling the specific requirements of LIDAR application.
Our consortium proposes to design a LIDAR dedicated multi-channel read-out chip prototype focusing our R&D on bandwidth and fast return to baseline to fulfil LIDAR requirements.