An optical filter having at least one optical fiber component and a thermal compensation
device which includes a first, second and third member in which the thermal compensation
device has a first and a second fixing point, the first, second and third members
are made from materials having first, second and third thermal expansion coefficients,
the optical fiber component is attached to the thermal compensation device at the
first and the second fixing points thus defining a composite thermal expansion.
The optical filter is such that the composite thermal expansion compensates for
thermal behavior of the optical fiber component.