Dual-Focus DOE Fiber Coupling With Shared Beam Tracking
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Solution Overview
Problem
Optical communications systems require separate optical paths for beam acquisition and tracking, and fiber coupling, necessitating two fast steering mechanisms with tight alignment tolerances, which increases size, cost, and complexity.
Innovation Solution
A dual focus diffractive optical element (DOE) combines beam tracking and fiber coupling functions into a single optical path using a hybrid sensor assembly with a tracking sensor and a fiber, eliminating the need for separate alignment mechanisms and reducing structural and thermal distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate optical paths are used for beam acquisition/tracking and fiber coupling, then alignment precision can be maintained, but device complexity and size increase due to requiring two fast steering mechanisms
Solution Approach 1:
The patent combines beam tracking and fiber coupling functions into a single shared optical path, eliminating the need for separate fast steering mechanisms. The incoming beam is directly focused by a lens onto both the tracking sensor and the fiber, reducing system complexity while maintaining alignment precision through the inherent optical focusing geometry.
Solution Approach 2:
The single optical path serves multiple functions simultaneously: it enables both beam acquisition/tracking and fiber coupling. The tracking sensor and fiber share the same incoming beam path, allowing one optical channel to perform what previously required two separate systems.
2Measurement precision
If two fast steering mechanisms are used for tight alignment tolerances, then alignment precision is improved, but weight increases
Solution Approach 1:
By merging the tracking and coupling functions into a single optical path, the patent eliminates one fast steering mechanism entirely. This reduction in moving components directly decreases system weight while the optical focusing geometry maintains the necessary alignment precision.
3Measurement precision
If separate optical paths are used for tracking and fiber coupling, then tracking accuracy can be maintained, but manufacturing cost increases
Solution Approach 1:
The patent reduces manufacturing cost by consolidating two separate optical systems into one. Fewer optical components (lenses, mirrors, steering mechanisms) need to be procured, aligned, and integrated. The single optical path approach simplifies the bill of materials and assembly processes while maintaining tracking accuracy through direct optical focusing.
4Adaptability or versatility
If two separate optical paths are used, then functional versatility is maintained, but the system becomes more susceptible to structural and thermal distortions
Solution Approach 1:
By using a single shared optical path for both tracking and fiber coupling, the patent reduces the total number of optical components and mechanical structures. This consolidation minimizes the cumulative structural and thermal distortions that would affect multiple separate paths, thereby improving reliability and robustness.
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 combined optical path simplifies alignment, reduces component count, lowers cost and size, and enhances robustness against structural and thermal influences, while maintaining efficient power coupling and tracking.
Implementation Method 1
The metalens or DOE manipulates the phase of the optical beam and is designed to create a beam shape similar to a bulls-eye pattern having a center beam and an outer ring beam
Implementation Method 2
2-D metamaterials, also known as metasurfaces, can be designed and fabricated as structural units to achieve desired diffractive optical properties and functionalities, such as focusing light with low loss
Data Source
AI summary
An optical sensor assembly including a diffractive optical element (DOE) responsive to an optical input beam and a refractive lens responsive to a shaped optical beam from the DOE. The lens focuses the shaped optical beam to provide a center beam having a short focal length and an outer beam having a long focal length. A sensor is positioned in front of the long focal length and is responsive to the shaped input beam from the lens. A fiber is positioned within a center opening of the sensor so that an input facet of the fiber faces the DOE and is located at the first focal length. The sensor is positioned relative to the DOE and the position of the input beam is controlled so that the center beam impinges the input facet and the outer beam impinges the sensor.