Fitting method for spontaneous emission noise of laser radar system and optical fiber sensing system

A method for fitting spontaneous emission noise, which is applied to a lidar system or an optical fiber sensing system,

• wherein the lidar system comprises a signal source, a co-located transceiver module and a distributed transceiver module, the signal source is used to provide a trigger collection signal to simultaneously trigger the co-located transceiver module and the distributed transceiver module to detect a detection target, the co-located transceiver module has a first telescope for emitting a detection beam and receiving co-located data returned by the detection target, the distributed transceiver module has a second telescope for receiving distributed data returned by the detection target, and spontaneous emission noise is fitted based on the co-located data and the distributed data;
• wherein the optical fiber sensing system comprises a signal source, a laser, a circulator, an optical fiber disk, and an optical switch, the signal source is used to provide a trigger collection signal to trigger the laser to emit a detection beam to detect a detection target, the optical switch is used to control a switch of the circulator, the optical switch has a first state and a second state:
• in the first state, the optical switch is turned on, the detection beam is emitted through a first output end of the circulator, and then is output by the optical fiber disk, and co-located data is returned by the detection target based on the detection beam;
• and in the second state, the optical switch cuts off the first output end of the circulator, the detection beam enters the optical switch through a second output end of the circulator, and distributed data is received;
• wherein the method comprises:
• providing a trigger collection signal by a signal source;
• triggering, based on the trigger collection signal, a co-located transceiver module and a distributed transceiver module to perform synchronous detection on a detection target;
• receiving co-located data and distributed data returned by the detection target;
• subtracting local noise from the co-located data and the distributed data, respectively;
• selecting a linear interval to normalize the co-located data;
• performing subtraction operation on the normalized co-located data and the distributed data to obtain spontaneous emission noise;
• and
• fitting the spontaneous emission noise by a function.