Chirped FBGs 匚 I Longer Wavelengths Shorter Wavelengths A"is where you get a variation in the period of the le grating (and hence a variation in its response to different wavelengths)along the length of the grating vary the period of the grating or vary the average Ri of the gratingChirped FBGs • A “chirp” is where you get a variation in the period of the grating (and hence a variation in its response to different wavelengths) along the length of the grating: – vary the period of the grating or – vary the average RI of the grating