Patent ID: 8818193

Claim:
A tunable optical dispersion compensator comprising: a first beam displacer on an optical path, wherein the first beam displacer separates an input optical signal into a first beam and a second beam; a first half-wave plate attached to the first beam displacer and located in the optical path of both the first beam and the second beam; a first polarizing beam splitter including a garnet and a second half-wave plate on the optical path, wherein the optical path from the first beam displacer through the first half-wave plate and the first polarization beam splitter is linear in a first direction; two or more component sets cascaded together on the optical path, wherein each of the two or more component sets includes: a collinearly-located polarization beam splitter; a collinearly-located quarter-wave plate attached to the collinearly-located polarization beam splitter; a collinearly-located etalon; an orthogonally-located half-wave plate attached to the collinearly-located polarization beam splitter; an orthogonally-located polarization beam splitter; an orthogonally-located quarter-wave plate attached to the orthogonally-located polarization beam splitter; and an orthogonally-located etalon; wherein: the collinearly-located polarization beam splitter, the collinearly-located quarter-wave plate, and the collinearly-located etalon are collinearly aligned with each other parallel to the first direction and either collinear with the first beam displacer, the first half-wave plate, and the first polarization beam splitter or collinear with the orthogonally-located polarization beam splitter of a preceding one of the two or more component sets; and the collinearly-located polarization beam splitter, the orthogonally-located half-wave plate, the orthogonally-located polarization beam splitter, the orthogonally-located quarter-wave plate, and the orthogonally-located etalon are collinearly aligned with each other orthogonal to the first direction; wherein the collinearly-located and orthogonally-located etalons in the two or more component sets are tunable and produce a group delay in the first beam and the second beam; a reflecting mirror on the optical path collinearly aligned parallel to the first direction with the orthogonally-located polarization beam splitter of a last one of the two or more component sets, wherein the reflecting mirror returns the optical signal back along the optical path; and a second beam displacer on the optical path and positioned to receive the first beam and the second beam after reflection by the first polarization beam splitter in a direction orthogonal to the first direction, wherein the second beam displacer combines the first beam and the second beam into an output optical signal.