Optical low-coherence reflectometry using a Gaussian bandpass filter for measuring WDM components

We report that a tunable narrow-band light source using a Gaussian bandpass filter is indispensable for measuring the return loss of a wavelength-division-multiplexing component with an optical low coherence reflectometer. We used an arrayed-waveguide grating (AWG) to construct a 0.4 nm-wide Gaussian bandpass filter and successfully measured the reflection of a 100-GHz-spaced 1/spl times/6 AWG component.