please explain this for me:
fiber Bragg grating (FBG) sensors are fabricated by illuminating a short length of single mode optical fiber by ultra-violet light under a phase mask. The FBG acts as a band-stop filter reflecting optical signals whose wavelength is determine by the phase mask period
fiber Bragg grating (FBG) sensors are fabricated by illuminating a short length of single mode optical fiber by ultra-violet light under a phase mask. The FBG acts as a band-stop filter reflecting optical signals whose wavelength is determine by the phase mask period