Optical waveguide devices are indispensable in various high technology industrial applications, and especially in telecommunications. In recent years, these devices, including planar waveguides, and two or three dimensional photonic crystals are being used increasingly in conjunction with conventional optical fibers. In particular, optical waveguide devices based on chiral optical fibers are advantageous and desirable in applications in which conventional optical fibers are also utilized. However, there are significant challenges in interfacing optical waveguide devices, including chiral optical fiber devices, with conventional low index contrast optical fibers. Typically, at least two major obstacles must be dealt with: (1) the difference between the diameters of the optical waveguide device and the conventional fiber (especially with respect to the differences in core sizes), and (2) the difference between the numerical apertures of the optical waveguide device and the conventional fiber. Failure to properly address these obstacles results in increased insertion losses and a decreased coupling coefficient at each interface.
A commonly assigned U.S. Pat. No. 7,308,173, entitled “OPTICAL FIBER COUPLER WITH LOW LOSS AND HIGH COUPLING COEFFICIENT AND METHOD OF FABRICATION THEREOF”, which is hereby incorporated herein in its entirety, advantageously addressed all of the above issues by providing various embodiments of a novel optical fiber coupler capable of providing a low loss, high coupling coefficient interface between conventional optical fibers and optical waveguide devices.
Nevertheless, a number of challenges still remain. With the proliferation of optical devices with multiple waveguide interfaces (e.g., waveguide arrays), establishing low loss high-accuracy connections to arrays of high numerical aperture waveguides often provide problematic, especially because the spacing between the waveguides was very small making coupling thereto all the more difficult.
It would thus be desirable to provide an optical fiber coupler array that provides a high coupling coefficient interface with high accuracy and easy alignment between an optical waveguide device having a plurality of high numerical aperture waveguide interfaces, and a plurality of optical fibers each having low numerical apertures.