Optical resonant cavity coupling structure, manufacturing method and ultrasonic detector

The invention provides an optical resonant cavity coupling structure, a manufacturing method and an ultrasonic detector, and relates to the technical field of ultrasonic detection. The optical resonant cavity coupling structure comprises an optical fiber coupling assembly and an optical branching assembly. When the resonant frequency of the resonant cavity is included in the gain range of the laser, part of the laser enters the second conical optical fiber from the resonant cavity and enters the laser source sequentially through the second port and the first port through the optical branching assembly, and self-injection locking of the laser source is achieved. When the gain range of the laser entering the resonant cavity through the optical branching assembly does not contain the resonant frequency of the resonant cavity, the gain range of the laser is adjusted to contain the resonant frequency of the resonant cavity, and then self-injection locking of the laser source is achieved. According to the ultrasoni