Optical signal routing devices and systems

One example LIDAR device comprises a substrate and a waveguide disposed on the substrate. A first section of the waveguide extends lengthwise on the substrate in a first direction. A second section of the waveguide extends lengthwise on the substrate in a second direction different than the first direction. A third section of the waveguide extends lengthwise on the substrate in a third direction different than the second direction. The second section extends lengthwise between the first section and the second section. The LIDAR device also comprises a light emitter configured to emit light. The waveguide is configured to guide the light inside the first section toward the second section, inside the second section toward the third section, and inside the third section away from the second section.