Wavelength lockers, which monitor the wavelength drift of a laser's beam
due to aging, are tunable to adjust for manufacturing misalignments between its
various optical components. Tuning is accomplished by adjusting the position of
a collimating lens using a flexure. Adjusting the lens position changes the angle
of incidence of a monitored beam relative to a fixed filter and detector and avoids
the challenging manufacturing task of rotating the filter and detector to achieve
the same result.
