Compact silicon photonics-based laser modules for FM-CW LIDAR and RFOG

摘要

Narrow-linewidth semiconductor lasers, micro-optics, silicon photonics (SiP), low noise electronics and high-densitypackaging are key elements for the development of compact high-end light sources for sensing.A laser module for the interrogation of an RFOG (Resonant Fiber-Optic Gyroscope) includes three distributed feedbacklasers coupled with micro-lenses to a multi-component SiP chip that performs beat note detection and several otherfunctions. The lasers and SiP chip are packaged in a 2.6 cm3 multi-layer ceramic package, a 4x volume reduction over afirst generation module. The package interfaces with 92 electrical pins and two fiber pigtails, one carrying the signalsfrom a master and slave lasers, another carrying that from a second slave laser. The complete laser source includingelectronics is 60 mm in diameter and 23 mm in height, a 10x volume improvement over a previous version. The masterlaser can be locked to the RFOG resonator with a loop bandwidth greater than 1 MHz. The slave lasers are offsetfrequency locked to the master laser with loop bandwidths greater than 100 MHz. This high performance source iscompact, automated, robust, and remains locked for days.A lighter version of this laser module for FM-CW LIDAR applications produces an output optical frequency that varieslinearly as a function of the electrical drive. A triangular modulation at 100 kHz with a greater than 1 GHz amplitude hasbeen demonstrated with a linearity noise near 1 MHz as measured through a 150 m unbalanced interferometer.