Light source for frequency-modulated continuous wave (FMCW) LiDAR device

A light source for a frequency-modulated continuous-wave (FMCW) LiDAR device, wherein the light source is formed by a photonic integrated circuit and comprises:

• a substrate, a multilayer structure supported by the substrate, wherein at least the following functional elements are formed by the multilayer structure:
• an input optical waveguide, an output optical waveguide and a cavity optical waveguide,
• an optical splitter connecting the input optical waveguide both to the output optical waveguide and to the cavity optical waveguide,
• a reflector connected to the cavity optical waveguide, and
• a variable attenuator causing an attenuation of light guided in the cavity optical waveguide,
• a semiconductor laser that is
• received in a recess etched into the multilayer structure and
• connected to the input optical waveguide such than an optical path extending between the semiconductor laser and the reflector and including the optical splitter forms an external cavity for the semiconductor laser,
• a first electrical line connected to the semiconductor laser so as to supply the semiconductor laser with a varying operating current, wherein the semiconductor laser is configured to produce light having a frequency that varies synchronously with the supplied operating current,
• a second electrical line connected to the variable attenuator so that the attenuation caused by the attenuator depends on electrical signals that are supplied to the variable attenuator via the second electrical line, and
• an electronic control module configured to supply the variable attenuator with electrical signals so that the variable attenuator causes a constant attenuation that is determined on a basis of measurements of the performance of the light source such that a linewidth of the semiconductor laser has a minimum.