The invention discloses a protecting method from microwave breakdown in the waveguide, which character is that a small hole is opened on the waveguide wall, and then an airtight stainless steel pipe is sealed around hole, in which, a quartz glass window with a group of focusing lens and valve tube airtight components are located. The breakdown strike fire reaches the group of focusing lens and focuses on the face of optical fiber cable through the quartz glass window, which transmits the optical signals to the environment far from radiation to take photoelectric conversion and converts into the pulse signals to turn off the microwave switch through the optical isolator driver. The invention uses the condenser lens and optical fiber cable to transmit the optical signals of breakdown fire, so that the fire in the waveguide can be detected in the place far from microwave and nuclear radiation. |