Preparation method of optical fiber microcavity coupling system and ultrasonic detector

The embodiment of the invention discloses a preparation method of an optical fiber microcavity coupling system and an ultrasonic detector. The preparation method of the optical fiber microcavity coupling system comprises the steps that firstly, a microsphere cavity assembly is provided; then, a bent optical fiber assembly is provided, the bent optical fiber assembly comprises a tapering optical fiber, the middle part of the tapering optical fiber is bent to form an annular structure, and the two ends of the tapering optical fiber are mutually rotated and wound; adjusting a microsphere cavity of the microsphere cavity assembly to be coupled with an annular structure of the bent optical fiber assembly; and finally, sequentially fixing the microballoon cavity of the microballoon cavity assembly and the coupling part of the annular structure of the bent optical fiber assembly, and fixing the optical fiber support rod of the microballoon cavity assembly and the extension parts at the two ends of the bent optical f