Optical sensor chip

A LIDAR system, comprising:

• a LIDAR chip with a ridge waveguide configured to guide an outgoing LIDAR signal and a LIDAR input signal,
• the LIDAR input signal including light from the LIDAR output signal after an object located outside of the LIDAR system reflects the light from the LIDAR output signal,
• the ridge waveguide including a ridge of a light-transmitting medium extending away from slab regions of the light-transmitting medium,
• the ridge having a width greater than 1 μm and less than 4 μm,
• the ridge having a height greater than 1 μm and less than 4 μm, and
• the slab regions having a thickness greater than 0.5 μm and less than 3μm;
• the LIDAR chip including a coupler configured to couple a portion of the outgoing LIDAR signal from the ridge waveguide onto a reference waveguide as a reference signal and also to couple a portion of the LIDAR input signal from the ridge waveguide onto a comparative waveguide as a comparative signal;
• the LIDAR chip configured to generate a composite signal having light from the reference signal beating with light from the comparative singal;
• and
• electronics configured to use the composite signal to generate LIDAR data that includes the distance between the LIDAR chip and the object.