Optical Array Connector Using Expanded-Beam Alignment

The patent introduces curved coupling surfaces (microlens arrays or curved flat surfaces) as intermediary elements between the first and second waveguide arrays. These coupling surfaces expand and collimate the optical beams, creating a larger effective coupling area that tolerates mechanical misalignments. The intermediary surfaces act as a buffer zone that decouples the mechanical connection requirements from the optical alignment requirements, allowing straightforward mechanical assembly while achieving precise optical coupling.

The patent changes the optical parameters by expanding the beam diameter through the curved coupling surfaces. By transforming the small cross-section beams into larger expanded beams, the system becomes less sensitive to alignment errors. The curvature of the coupling surfaces modifies the beam propagation characteristics, enabling tolerance to lateral and angular misalignments while maintaining high coupling efficiency.

The patent employs curved coupling surfaces (spherical or aspherical surfaces, including microlens arrays) that transform the small cross-section beam profiles into expanded, collimated beams. The curvature of these surfaces is specifically designed to match the waveguide parameters and achieve optimal beam expansion. This curvature-based approach maintains the benefits of small cross-section waveguides for high integration density while eliminating alignment sensitivity through beam expansion.

The patent transitions from direct end-face coupling in one dimension to curved surface coupling that operates in multiple dimensions. The curved surfaces introduce additional spatial dimensions for beam manipulation, allowing the system to tolerate misalignments in lateral and angular directions. This dimensional approach enables robust coupling despite the small cross-sections of the integrated waveguides.

The patent incorporates curved coupling surfaces that can be integrated into the waveguide array structures. These curved surfaces (including microlens arrays) provide misalignment tolerance through beam expansion while maintaining relatively simple device architecture. The curvature is achieved through standard fabrication techniques, balancing the need for misalignment tolerance with device simplicity.

The patent merges the coupling function with the waveguide array structure itself. Rather than adding separate, complex alignment mechanisms, the curved coupling surfaces are integrated directly into the waveguide arrays, combining the structural and optical coupling functions. This integration achieves misalignment tolerance without significantly increasing device complexity.