FBG vibration detection system, apparatus and vibration detection method using the system

摘要

A vibration detection apparatus for, for example, ultrasound/AE, with Fiber Bragg Grating (FBG), is used for elastic wave detection generated by a material impact and ultrasonic defect detection. Disadvantageously, the apparatus cannot detect ultrasound and has degraded performance at variable temperatures and strains. In response, a highly sensitive, small and light vibration detection apparatus is provided. FBG reflection light is lased by using a fiber laser. The intensity of the lased reflection light from the FBG is converted into an electrical signal. Thus, the ultrasound vibration or the like is detected. A vibration detection system includes an optical amplifier 42, an optical circulator 43, and an optical coupler 45. An FBG 44 and an entry/exit port of the optical circulator are connected by an optical fiber. The optical coupler and the optical amplifier are inserted between an entry port and an exit port of the optical circulator. The entry port and the exit port are connected by an optical fiber.

主权项

1. A vibration detection system for detecting vibration, the system comprising:
a fiber laser including:
a Fiber Bragg Grating (FBG) operating as a reflection mirror of the fiber laser, such that the fiber laser has a resonant structure, andan opto-electrical conversion unit converting intensity of reflection light from the FBG into an electrical signal, the reflection light being lased by the fiber laser; an optical amplifier; an optical circulator; and an optical coupler, wherein the fiber laser has a lasing wavelength at the Bragg wavelength of the FBG, the Bragg wavelength being determined by the optical amplifier configured for optical amplification in a wavelength range that comprises a reflection wavelength of the FBG by using the FBG for a sensor operating as a reflection mirror.