There are so many innovations coming up today. Unfortunately, FMCW LiDAR is one of the overrated new technologies. LIDAR (Light Detection and Ranging) is considered the most crucial technology for self-propelled vehicles. According to experts, Frequency Modulated Continuous Wave (FMCW) LIDAR will help the breakthrough in autonomous driving and entirely phase out the currently employed Time of Light (TOF) LIDAR systems.
Autonomous driving is the automotive industry’s leading source of innovation. In addition, the entire mobile ecosystem will be transformed by self-driving cars, autonomous taxis, delivery services, and buses.
Autonomous driving can fundamentally disrupt the automobile industry’s traditional supply chain or introduce entirely new players. Mobileye, an Intel business, was recently permitted to test the technology in Munich, Bavaria. Intel.
FMCW RADAR is already available as a standard driver aid system in the car sector. Unlike radar, FMCW LiDAR uses light in lasers rather than radio waves, allowing superior image resolution and object recognition, such as walkers and bicycles.
Benefits of FMCW LiDAR
Compared to traditional approaches, this FMCW LiDAR technology offers tremendous benefits.
- Range of more than 250 meters and resistance to adverse weather and direct sunshine
- Sensor cross-talk and self-interference are not a problem since light impulses from other sensors are not confused or disrupted.
- Simultaneous distance and speed measurements in each data point, resulting in reduced processing effort and system costs.
- Low cost and scalability can be achieved using highly integrated Photonic Integration Circuits.
- Furthermore, it can deliver precise measurement results even in low-visibility situations, such as fog, rain, or snowfall. Sentinel also employs a freshly created beam deflection mechanism free of mechanical components like MEMS.
Advantages of FMCW LiDAR Over Conventional LiDAR
The FMCW LiDAR technique has several advantages over traditional “direct detect” LiDAR methods, including the following:
- Range resolution has been improved, allowing for measuring and separating multiple closely spaced surfaces.
- The improved dynamic range allows for simultaneous measurement of bright and dim objects.
- Single-photon sensitivity allows for small apertures, long-distance operation, and obscurant penetration.
- Velocity sensitivity allows for the detection and quantification of motion.
Uses of FMCW LiDAR
Powering Autonomous Vehicles
Aeries I is the first 4D LiDAR sensing system that meets perception requirements for autonomous vehicle development and testing and industrial programs. This all-in-one system combines LiDAR, camera, and processing electronics to produce uniquely rich data that meets perception needs by leveraging a unique design of Frequency Modulated Continuous Wave (FMCW) technology.
Lumentum is developing an FMCW LiDAR optical subassembly (LOSA) to address the challenges associated with long-range LiDAR. This novel approach integrates all visual elements, including the laser, laser monitor, detector, mixer, receiver, scanning mirror, and circulator. It takes advantage of our decades of optical integration design experience to reduce FMCW LiDAR’s cost, size, power consumption, and complexity.
Products Using FMCW LiDAR
Visual Communication
The optical components and modules are used globally in virtually every communication network, including telecom, enterprise, and data center networks.
Lumentum’s comprehensive, vertically integrated portfolio includes laser chips (EMLs, DMLs, and VCSELs), pluggable coherent transceivers, pump lasers, and TrueFlex® colorless, directionless. It is vital to optimizing the components for best-in-class performance, resulting in flexible and scalable platforms that can address constantly changing market conditions and product migrations. In addition, Lumentum uses only the best materials and processes to ensure field reliability, including stringent, proprietary burn-in procedures during laser manufacturing.
Submarine Elements
Best-in-class reliability, performance, and product breadth enable intercontinental undersea communication networks globally.
Modules and passive components
A solid vertical integration capability aids module design and manufacturing.
Amplifiers for Optical Signals
It is the industry’s most comprehensive portfolio of high-performance amplifiers.
Commercial Lasers
kW class fiber lasers, ultrafast solid-state lasers, UV Q-switched diode-pumped lasers, and low-power continuous-wave lasers are among the commercial laser products available.
Lumentum provides OEM customers with the most comprehensive range of laser modules, engines, and components. These lasers offer a wide range of extreme operational performance, proprietary SESAM technology, direct-process fiber connect processes, high pulse-to-pulse stability, highest stability and reliability, and low noise with excellent beam quality. In addition, our lasers consistently set industry benchmarks in terms of dependability and longevity.
FMCW LiDAR Systems vs. Time of Flight Systems
FMCW is a New Revolting Technology.
Contrary to popular belief, FMCW LiDAR has been around for a long time, dating back to 1960s research at MIT Lincoln Laboratory8, only seven years after the invention of the laser itself9. Unfortunately, many of the FMCW lessons learned over the years, while unclassified and in the public domain, have been forgotten. What has recently changed is the increased availability of long coherence-length lasers. While this has rekindled interest in the established technology by theoretically providing an extremely high signal gain, it is vital to address several limitations of LiDAR before using it in autonomous vehicles.
FMCW Accurately and Efficiently Measures Velocity and Range
It is one of the most deceptive claims. ToF systems, including AEye’s LiDAR, require multiple laser shots to determine target velocity. Compared to the claims of FMCW with single images, this may appear to be extra overhead. Much more important is realizing that not all velocity measurements are created equal. While radial velocity in two cars colliding is critical (one of the reasons a more extended detection range is desirable), so is lateral velocity, which accounts for more than 90% of the most difficult edge cases. Cars running red lights, swerving vehicles, and pedestrians crossing the street require lateral velocity to make evasive decisions. FMCW cannot measure lateral acceleration simultaneously in a single shot, thus providing no benefit.
FMCW detects and tracks objects further and faster.
There is no proof of this claim. ToF LiDAR systems can provide high-speed laser shot rates (up to several million shots per second in the AEye system), agile scanning, increased return salience, and the ability to apply high-density Regions of Interest (ROIs) — providing two- to four-times better information from returns than other systems. However, many low-complexity FMCW systems can only achieve shot rates in the tens to hundreds of thousands of shots per second 50 times slower.
Summary
When cost, range, performance, and point cloud quality are essential. AEyebelieves that high-performance, agile-scanning ToF systems serve the needs of autonomous vehicle LiDAR better than FMCW. However, it is easy to see the logical reasoning for FMCW playing a niche role in applications where lower shot rates are appropriate and FMCW systems are more cost-effective.
