Dr. Sidi Aboujja from SemiNex presented two technical talks on our latest SOA array and highly reliable Triple Junction for automotive LiDARs at SPIE Photonics West 2023 last week. These talks capture the technological advancements and application insights so that LiDAR can achieve long range with low cost and small form factors. The abstracts of these talks are listed below.
Technical Paper: High performance semiconductor optical amplifier and array for FMCW LiDAR in high-speed autonomous vehicles
We present an industry-leading semiconductor optical amplifier (SOA) platform that exhibits top performance at both 1550nm and 1310nm used in FMCW (frequency-modulated continuous-wave) LiDAR (Light Detection and Ranging) for autonomous vehicles. The SOA structure is based on a proprietary AlInGaAs material system with multiple quantum wells on InP substrate. The SOAs with curved and tilted straight waveguides were developed and tested. The saturated output power of such SOA at 1550nm and 1310nm can reach higher than 450mW and 600mW. An array of four SOA waveguides at 127um or 500um pitch can deliver total output power over 2 Watts. SOA arrays can also be processed as individually addressable with electrical and optical isolations. Such high performance offers the design freedom to LiDAR systems with various scanning strategies such that long range detection can be realized. The low anti-reflection (AR) coating can achieve 0.01% reflectivity, and the noise figure and near-field mode fields of various SOA configurations are presented and compared. Gain chip based on the curved waveguide for various laser configurations is tested and discussed. The SOA chips and arrays can be integrated into a Silicon Photonic Integrated Circuit (Si PIC) to minimize the total footprint of a LiDAR system and overall cost. They include self-alignment features for the ease of integration and high coupling efficiency on Si PIC.
Technical Paper: High reliability of 1550nm triple junction laser diode for long-range automotive LiDAR
We have developed the world-leading Triple Junction laser diode based on AlInGaAs/InP material systems for LiDAR applications. The monolithic laser structure with tunnel junction layers is designed to reduce the stress and improve the heat dissipation. It has 3x the output power and 2x the wall plug efficiency of a single junction laser due to its low operating voltage and high slope efficiency at 1W/A. A single Triple Junction laser diode at eye-safe 1550nm allows a LiDAR to achieve over 200m detection range in all-weather conditions. It can drastically improve and simplify the LiDAR design compared to other laser choices such as 905nm or fiber lasers. For mass adoption by the automotive industry here we demonstrate the high reliability required for Triple Junction high power laser diodes at 1550nm. The life test was performed on 95um aperture Triple Junction with 2.5mm cavity length in a TO9 package. They were driven at an average power of 700mW with the pulse width of 100 micro-seconds and 10% duty cycle at 90°C. Such stressed electrical and temperature condition is almost 20 times higher than standard operation for automotive LiDAR. We have accumulated for more than 1000 hours of life test on 30 devices. Based on Chi squared distribution analysis and Arrhenius equation the estimated MTTF (mean time to failure) is 248k hours at 20°C and 57k hours at 50°C operating temperature, which is respectively 31x and 7x more than the required 8k hours in automotive applications. We also tested Triple Junction laser diodes up to 100°C without performance degradation and without COD (catastrophic optical damage).
SemiNex is more than happy to work with you on the design-in effort or custom design requests to meet the requirements in your integrated LiDAR systems. For inquiries regarding product offerings, custom designs and future projects with SemiNex, as well as scheduling a meeting with us, contact email@example.com or +1-978-326-7703. Details on the Triple Junction laser diodes and SOAs are available at seminex.com/lidar/.