System and method for using combining couplers with asymmetric split ratios in a lidar system
View Patent ↗A laser radar, or “lidar” system, employs an asymmetric single-ended detector to detect received signals reflected back from targets. The asymmetric single-ended detector benefits from a reduced part count and fewer optical splices while nearly achieving a same gain as a symmetric differential detector.
1. A lidar comprising:
a laser source configured to generate a laser output;
a splitter configured to split the laser output into a transmit signal and a mixing signal; and
a single-ended detector comprising:
an asymmetric combiner configured to combine a received signal and the mixing signal and output a combined signal, wherein the received signal is a reflected portion of the transmit signal reflected back from a target and received by the lidar, wherein the asymmetric combiner has a power split ratio greater than 0.5, and
a detector configured to detect the combined signal.
2. The lidar of claim 1 , wherein the asymmetric combiner has a power split ratio greater than or equal to 0.6.
3. The lidar of claim 1 , wherein the asymmetric combiner has a power split ratio greater than or equal to 0.7.
4. The lidar of claim 1 , wherein the asymmetric combiner has a power split ratio greater than or equal to 0.8.
5. The lidar of claim 1 , wherein the asymmetric combiner has a power split ratio greater than or equal to 0.9.
6. The lidar of claim 1 , wherein the asymmetric combiner has an empirical power split ratio of 0.8.
7. The lidar of claim 1 , wherein the asymmetric combiner has an empirical power split ratio of 0.9.
8. The lidar of claim 1 , wherein the asymmetric combiner comprises an asymmetric combining coupler.
9. The lidar of claim 1 , wherein the detector comprises a PIN diode.
10. The lidar of claim 1 , further comprising a gain stage or an attenuation stage configured to adjust a power level of the mixing signal prior to input to the asymmetric combiner.