Multiple-Depth Polarization Beam Splitter-Rotator for TM-to-TE Conversion

The optical device is segmented into multiple functional sections: a rotation section with multiple slabs of different thicknesses (first slab, second slab, third slab) for progressive TM mode suppression, and a splitter section with waveguides for signal distribution. Each slab is positioned at specific heights above the substrate to progressively rotate and suppress TM modes, achieving efficient conversion to TE mode while maintaining signal quality.

The patent utilizes the vertical dimension (height above substrate) to create slabs at different elevation levels. The first slab is positioned at a first height, the second slab at a second height, and the third slab at a third height, all above the substrate. This vertical stacking creates a three-dimensional structure that progressively rotates TM modes through multiple interfaces, achieving efficient mode conversion that planar structures cannot accomplish.

The patent merges the polarization rotation function and the beam splitting function into a single integrated device structure. The rotation section with multiple slabs performs TM mode suppression and rotation, while the splitter section with coupled waveguides performs signal distribution. Both functions are implemented in one continuous structure formed from a single substrate, eliminating the need for separate components and reducing overall system complexity despite the sophisticated functionality.

The optical device serves multiple functions within a single structure: it acts as a polarization rotator to convert TM modes to TE modes, a beam splitter to distribute optical signals to multiple waveguides, and a mode suppressor to eliminate unwanted polarization components. This multi-functionality is achieved through the integrated design where the same slabs and waveguides perform multiple roles, reducing the number of separate components needed.