Device for preparing low-loss micro-nano fiber grating sensor by chemical etching method

The utility model relates to a device for preparing a low-loss micro-nano fiber grating sensor by a chemical etching method, which comprises a broadband light source, a fiber circulator, a 3-dB fiber coupler, a spectrometer, an optical power meter, a stepping motor, a fiber written with Bragg grating, and a polytetrafluoroethylene container containing a corrosive solution. An optical signal of the broadband light source reaches the fiber Bragg grating via the fiber circulator while a reflection signal of the fiber Bragg grating is output to the 3-dB fiber coupler via the fiber circulator; the 3-dB fiber coupler transmits the reflection signal of the fiber Bragg grating to the spectrometer and the optical power meter; the tail end of the fiber written with Bragg grating is vertically dipped into the polytetrafluoroethylene container containing a corrosive solution, and the upper end of the same is fixed on the stepping motor; and the stepping motor increases the fiber speed and is controlled by a computer in r