Optical Couplers with Non-Linear Tapering for Compact Photonics
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Solution Overview
Problem
Conventional adiabatic 3-dB optical couplers in photonics chips have a large footprint, are wavelength dependent, and sensitive to fabrication errors, leading to high insertion loss and inefficient light coupling.
Innovation Solution
The design incorporates two tapered waveguide cores with non-linear functions defining their shapes, allowing for close proximity and directional coupling with reduced sensitivity to fabrication variations and wavelength independence, achieving a 50%-50% light splitting ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If conventional adiabatic 3-dB optical couplers are used, then light coupling function is achieved, but the footprint area is large
Solution Approach 1:
The patent applies parameter changes by modifying the taper profile from conventional linear or exponential functions to optimized non-linear functions (e.g., power law functions with specific exponents). This changes the geometric parameters of the waveguide taper to achieve better mode field matching over a shorter interaction length, thereby reducing the footprint area while maintaining reliable 50:50 coupling efficiency.
2Adaptability or versatility
If conventional adiabatic 3-dB optical couplers are used, then light coupling function is achieved, but the device is wavelength dependent
Solution Approach 1:
The optimized non-linear taper profiles are designed with specific mathematical parameters (power law exponents, normalization factors) that create a more gradual and controlled mode field transformation. This parameter optimization makes the coupling mechanism less sensitive to wavelength variations and fabrication tolerances, achieving wavelength independence and reduced fabrication sensitivity simultaneously.
3Loss of energy
If conventional adiabatic 3-dB optical couplers are used, then light coupling function is achieved, but insertion loss is high
Solution Approach 1:
By optimizing the taper profile parameters to follow specific non-linear functions, the patent achieves more efficient adiabatic mode coupling that minimizes radiation losses and reflection losses. The optimized parameters enable the coupler to achieve the required 50:50 splitting ratio with lower insertion loss over a compact interaction length, resolving the contradiction between energy loss and device length.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a compact, wavelength-independent optical coupler with reduced sensitivity to fabrication errors, enabling efficient light coupling and increased layout area on photonics chips.
Implementation Method 1
Conventional adiabatic 3-dB optical couplers are 2×2 couplers that may be used in a photonics chip for coupling/splitting light evenly
Implementation Method 2
The first tapered section has a first shape determined by a first non-linear function, and the second tapered section has a second shape determined by a second non-linear function
Data Source
AI summary
Structures for an optical coupler and methods of fabricating a structure for an optical coupler. A first waveguide core has a first tapered section and a second waveguide core has a second tapered section positioned adjacent to the first tapered section. The first tapered section has a first shape determined by a first non-linear function, and the second tapered section has a second shape determined by a second non-linear function.