Evanescent couplers and related methods
AssigneeCisco Technology, Inc.
InventorTymon Barwicz
Life of this patent
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Abstract
In part, the disclosure relates to an optical coupler. The optical coupler may include two ridge waveguides that include a first waveguide and a second waveguide. One or more segments of the two waveguides extend over a coupling length or other distance. One or more sections of each ridge waveguide is at least partially defined by a set of cross-sectional profiles, a plurality of sections of each ridge waveguide have a width that tapers along a length of the two ridge waveguides. Within the coupling length, a subset of the set of cross-sectional profiles may define a first pair of transition regions and a second pair of transition regions. The coupler may include a coupling region between the two ridge waveguides and spanning at least a section of the coupling length.
Claims21
An optical coupler comprising:
- two ridge waveguides comprising a first waveguide and a second waveguide, wherein one or more segments of the two waveguides are extended over a coupling length, wherein one or more sections of each ridge waveguide is at least partially defined by a set of cross-sectional profiles, a plurality of sections of each ridge waveguide have a width that tapers along a length of the two ridge waveguides,
- wherein within the coupling length a subset of the set of cross-sectional profiles define a first pair of transition regions and a second pair of transition regions;
- and
- a coupling region between the two ridge waveguides and spanning at least a section of the coupling length, wherein the first pair of transition regions are a first pair of steps, each of the first pair of steps defined by a first etch depth along an outer or inner surface of each ridge waveguide, wherein the second pair of transition regions are a second pair of steps, each of the second pair of steps defined by a second etch depth along an outer or inner surface of each of the first pair of steps.
An evanescent coupler comprising:
- two waveguides comprising an incoming waveguide and an outgoing waveguide, wherein the two waveguides are extended over a coupling length;
- a coupling region between the two waveguides and spanning the coupling length, wherein the two waveguides are spaced at a predetermined range from each other to couple evanescent waves from the incoming waveguide to the outgoing waveguide over the coupling region, wherein the two waveguides adiabatically transition from a first elongate section comprising a pair of one-layer ridge waveguides to a second elongate section comprising a pair of two-layer ridge waveguides having a gap defined between a first layer of two layers of the two-layer ridge waveguides, wherein a side of each of the two-layer ridge waveguides is defined by a first step and a second step, wherein the first step is defined by the first layer of each of the two-layer ridge waveguides;
- a surface layer for supporting the two waveguides;
- a confinement layer for providing a vertical confinement of light for the two waveguides;
- a shared reflector truncating the coupling region of the evanescent coupler at an angle approximately normal to the two waveguides;
- and
- a substrate, wherein the two waveguides are formed in or upon the substrate.
A method for reversing a direction of light propagation in an evanescent coupler, the method comprising:
- propagating light through an optical input of an evanescent coupler in optical communication with a first ridge waveguide;
- transmitting the light through a plurality of sections of a first ridge waveguide, wherein one of the sections of the first ridge waveguide is separated from a second ridge waveguide by a gap such that an optical coupling length is defined, wherein one of the sections of the first ridge wave guide defines a first outer step and a second outer step, wherein one of the sections of the second ridge wave guide defines a first outer step and a second outer step;
- transmitting the light along the optical coupling length, wherein the first ridge waveguide and the second ridge waveguide are spaced at a predetermined range from each other to couple evanescent waves from the first ridge waveguide to the second ridge waveguide over the coupling length to achieve about 40 to about 60% power coupling;
- reflecting light from one or both of the first ridge waveguide and the second ridge waveguide at a single angled reflective surface that terminates the first ridge waveguide and the second ridge waveguide and is optically coupled therewith, wherein an angle of the angled reflective surface ranges from about 1 degrees to about 5 degrees;
- continuing the evanescent coupling of the reflected light from the single angled reflective surface to achieve approximately 100% power coupling into the second ridge waveguide;
- and
- transmitting at least a portion of the reflected light from an optical output in optical communication with the second ridge waveguide.
Dependencies are inferred from the claim text.