A method for aligning the spectral responses of two comb-like optical
filters is provided. This method does not necessitate the use of
spectrally-resolved equipment, as it uses the optical power correlation
profile of a broadband light signal representative of the combined
spectral responses of the two filters. In one embodiment, the power
correlation profile is compared to a pre-stored profile. A tuning method
for tuning two filters using this alignment method is also provided. The
two filters are first relaxed to an unstretched position, and the second
filter is stretched and aligned with the first. The first filter is also
stretched and aligned with the other. Both filters are then stretched at
a calibrated value.