An improved etalon has a bulk optic defining the optic cavity between
selectively transparent thin film mirror coatings. The bulk optic
comprises an optically transparent body, such as a portion of a substrate
wafer, along with a wedge correcting coating on at least one of the two
surfaces of the optically transparent body and/or a thickness-adjustment
layer on one or both surfaces. The wedge coating establishes high
precision parallelism of the selectively transparent surfaces of the
etalon. The bulk optic is a solid, self-supporting body, optically
transparent (at the wavelength or wavelengths of interest), whose
thickness, i.e., the dimension between the selectively transparent
surfaces, defines the cavity spacing of the etalon. Optical elements and
optical communication systems incorporating the novel etalons are
disclosed, as well as methods of producing the etalons.
