MIT Researchers Tout Low-Cost Lidar System

Researchers at the Massachusetts Institute of Technology’s Photonic Microsystems Group in Cambridge, Mass., are developing light-detection and ranging (lidar) sensors they claim will be considerably smaller, simpler, less expensive and better performing than current lidar systems.

The so-called lidar-on-a-chip technology has the potential to reduce production costs to as low as $10 per unit, the team estimates. This compares with $1,000 to as much as $70,000 for the lidar systems currently being tested in prototype autonomous vehicles. Several other companies are developing solid-state lidar that also promises to be much less expensive.

The MIT technology, which is detailed in the current issue of IEEE Spectrum, is described as a silicon photonic chip with steerable transmitting, receiving phased arrays and on-chip germanium photodetectors.

The chip, which is smaller than a dime and has no moving parts, uses thermal phase shifters to heat waveguides through which the laser propagates, changing the speed and phase of the light that passes through them. The lasers also could be integrated onto the chip in the future.

By eliminating the moving parts of conventional mechanical lidar systems, the researchers say the lidar-on-a-chip unit has the potential to be 1,000 times faster.

The rate of refraction varies depending on the temperature of the silicon. Notches fabricated in the silicon act as antennas, scattering the light out of the waveguide and generating emission patterns that combine to create a focused beam without a need for lenses.

The current test systems have a limited detection range of less than 7 ft. The researchers are targeting a fivefold increase within a year and aim to eventually expand the range to more than 300 ft.