Various methods, systems, and apparatuses in which a chromatic dispersion
compensation module includes an input fiber, an output fiber, a lens, and an etalon
resonator. The input fiber has a first core with a center. The output fiber has
a second core with a center. The input fiber is adjacent to the output fiber. The
spacing between the center of the first core and the center of the second core
is affixed to less than one hundred and twenty microns. The input fiber routes
an optical signal to a lens. The lens routes the optical signal to the etalon resonator.
The etalon resonator has reflectors with fixed reflectivity and a variable optical
length to induce a wavelength-dependent delay into the optical signal. The etalon
resonator routes the optical signal to the output fiber through the lens.
