Adiabatic Optical Coupler Tapering for Low Insertion Loss
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Solution Overview
Problem
Conventional optical couplers experience higher than desired losses due to optical energy being emitted in free space and coupling into undesired modes.
Innovation Solution
The optical coupler design features first and second cores with specific surface spacings and widths that taper adiabatically, reducing insertion loss by minimizing optical power loss to free space and undesired modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional optical coupler designs are used, then the device is simple to manufacture, but insertion loss is high due to optical energy emission in free space and coupling into undesired modes
Solution Approach 1:
The patent applies parameter changes by systematically varying the geometric parameters of the optical cores, including width, height, and spacing between cores. The cores feature tapered sections where dimensions change gradually along the propagation direction, transforming the optical mode profiles to minimize radiation losses and mode coupling into undesired modes. This parametric optimization directly reduces insertion loss while maintaining manufacturability through standard fabrication processes.
Solution Approach 2:
The patent implements dynamics through the tapered core结构设计, where the core dimensions are not static but vary continuously along the optical propagation path. The tapered sections create a dynamic transition of optical confinement, allowing the mode field to adapt gradually from one core to another, thereby minimizing abrupt discontinuities that cause radiation losses and mode coupling into undesired modes.
2Loss of energy
If conventional optical coupler designs are used, then the manufacturing process is straightforward, but optical power is lost to free space and undesired modes
Solution Approach 1:
The patent employs parameter changes by defining specific geometric parameters for the optical cores, including tapered sections with controlled width and height variations. These parametric designs optimize optical confinement and mode matching to reduce power loss to free space and undesired modes, while the parameters are chosen to be compatible with standard semiconductor fabrication processes, maintaining ease of manufacture.
3Loss of energy
If higher power sources are used to compensate for losses, then sufficient optical power is available, but non-linear effects increase
Solution Approach 1:
The patent converts the potential harm of high optical power (which causes non-linear effects) into a benefit by designing structures that efficiently guide and couple light with minimal losses. The tapered core configurations and optimized spacing create beneficial optical confinement and mode matching, reducing the need for high input power and thereby eliminating non-linear effects while maintaining sufficient output power.
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 design achieves lower insertion loss over a broader bandwidth, enabling the creation of a resonator with a higher quality factor that requires less optical power, thus using a lower power source and reducing non-linear effects.
Implementation Method 1
a first spacing between the first surface along the first portion of the first core and the second surface along the first portion of the second core adiabatically tapers narrower towards the second portions of the first and the second cores
Implementation Method 2
the second portion of the first core is optically connected between the first portion and the second portion of the first core
Implementation Method 3
each of the first and the second cores has an index of refraction higher than an index of refraction of the cladding
Data Source
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AI summary
Techniques are provided for implementing a low insertion loss optical coupler utilizing adiabatic tapering of spacings between two adjacent optical waveguides and tapering of a portion of one of the optical waveguides. An optical resonator with a higher quality factor may be formed using two of the low insertion loss optical couplers.