UV fine tuning of narrow channel fused fibre wavelength division multiplexing couplers
The wavelength response of fused fibre wavelength division multiplexers with channel spacings between 8 and 24 nm was altered by exposure to high intensity ultraviolet light. Wavelength shifts are shown to be the result of changes in the index of refraction of the glass in the fused region of the couplers, with effective index of refraction changes in the illuminated area estimated to be between 10–3 and 10–2.