Tunable optical filter - US 5073004 A
A tunable fiber Farby-Perot interferometer includes two aligned ferrule assemblies (22--22) having adjacent end faces separated by a gap. Each assembly includes a mirror (40) disposed transverse to a longitudinal axis (28) of the assembly and embedded internally therein adjacent to the exposed end surfaces which defines the gap. Each ferrule assembly is held in a sleeve (74) disposed in an end fixture (70) with a piezoelectric transducer system (44) extending between end fixtures. Means (82--82) are provided in each end fixture for deforming slightly the sleeve to cause the ferrule assembly disposed therein to be moved into alignment with the other. The transducer system is operated to adjust the length of the gap between the exposed adjacent end faces. Also, the facilities including the transducer system are provided such that a portion or portions of it may be operated selectively to fine tune further the alignment between the fibers.