A passive temperature-compensated optical grating arrangement includes a
housing of low CTE material, with the optical grating stretched across
the housing between a first, fixed sidewall and a lever arm, the lever
arm also being formed of a low CTE material. An expansion element of high
CTE material is attached to the frame and disposed to contact the lever
arm, resulting in rotating the lever arm as changes in temperature change
the dimensions of the expansion element. By properly sizing the lever arm
and the expansion element, changes in grating wavelength as a function of
temperature can be compensated for by adjusting the strain applied to the
grating as it is pulled or compressed as the lever arm is moved.