Polarization mixer based on walk-off crystals, half-wave plates and tec fibers

摘要

An optical subassembly (10; 62; 84; 98; 106; 136; 152) and a method for mixing polarization components (46A, 46B, 48A and 48B; 72A, 72B, 74A and 74B) of light signals using the same utilize an arrangement of walk-off crystals (12, 14, 20, 66, 68, 70, 86 and 110) and half-wave plates (22, 24, 26, 28, 90, 92, 94, 96, 102, 104, 108, 116, 118, 120, 122, 140, 142, 144, 156, 158 and 160). The optical subassembly can serve as a building block for fabricating a variety of optical devices such as optical circulators, switches and filters. Preferably, the optical subassembly is utilized in conjunction with optical fibers (32, 34 and 166) having thermally expanded cores. The optical elements of the subassembly are arranged such that the optical subassembly is able to separate polarization components of two light beams and recombine them to form two new light beams. A new light beams is formed by combining one polarization component from each of the two original light beams. Various arrangements of walk-off crystals and half-wave plates can be utilized to construct the optical subassembly in accordance with the invention. By attaching the optical subassembly with another optical assembly (162; 182), an optical device can be fabricated such as an optical circulator.