Tapered Optical Element Array for Photonic Integrated Circuits

The patent applies parameter changes by modifying the geometric parameters of the optical active element structure. Specifically, tapered regions are introduced with specific dimensions (width 5-20 μm, length 5-30 μm, height 1-3 μm) and angles (5-50 degrees) to reduce light reflection. This changes the physical parameters of the interface between optical elements and waveguides, thereby reducing reflective losses and improving optical transmission efficiency.

The patent employs curvature by introducing tapered regions with inclined surfaces instead of sharp edges or flat interfaces. The tapered structure creates gradual transitions in the optical path, reducing abrupt impedance mismatches that cause reflection. The curved or angled interfaces help match impedance between different optical components, minimizing reflective losses.

The patent applies segmentation by dividing the optical active element structure into distinct functional regions: tapered regions for impedance matching and flat regions for standard optical coupling. This segmentation allows each region to be optimized for its specific function while maintaining overall manufacturability. The structured division into manageable segments reduces the complexity of the overall design.

The patent applies local quality by introducing tapered regions only at specific locations (input and output regions of optical active elements) where impedance matching is most critical, rather than applying complex structures throughout the entire device. This localized approach reduces overall structural complexity while achieving the desired optical performance improvement at key interfaces.

The patent specifies optimal parameter ranges for the tapered regions (width 5-20 μm, length 5-30 μm, height 1-3 μm, angle 5-50 degrees) that balance reflection reduction performance with manufacturability. These parameter ranges are chosen to achieve effective impedance matching while remaining within the capabilities of standard semiconductor fabrication processes, thereby managing manufacturing precision requirements.

The patent employs etch selectivity between different materials (semiconductor material versus mask materials like SiN, silicon oxide, SOG, aluminum oxide, and BCB) to achieve the tapered structure. By utilizing materials with different etch rates, the complex tapered geometry can be formed through selective etching processes, reducing the need for high-precision direct patterning and lowering manufacturing precision requirements.