Integrated FSO Pointing Unit Steering Elements
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Solution Overview
Problem
Existing pointing units for free space optical communications terminals face challenges in efficiently steering beams over a wide range due to the separation of coarse and fine steering mechanisms, which increases the size, weight, and cost of the units.
Innovation Solution
A pointing unit with an optical arrangement comprising a pair of steering elements, one with a fixed refractive index and the other electro-optic, allowing for both coarse and fine steering control through orientation and refractive index variation, respectively, integrated into a single unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate coarse and fine steering mechanisms are used, then beam steering precision is improved, but device size and weight increase
Solution Approach 1:
The patent combines separate coarse steering and fine steering mechanisms into a single integrated optical arrangement. The coarse steering element (rotatable prism or mirror) and fine steering element (electro-optic or acousto-optic modulator) are merged into one compact unit, allowing both functions to be performed without requiring separate mechanical assemblies, thereby reducing overall weight while maintaining dual-stage steering precision.
Solution Approach 2:
The optical arrangement is designed to perform multiple functions within a single device: coarse steering through mechanical rotation, fine steering through electro-optic or acousto-optic modulation, and beam transmission. This multi-functional integration eliminates the need for separate dedicated components for each function, reducing weight and simplifying the overall system architecture.
2Measurement precision
If separate coarse and fine steering mechanisms are used, then beam steering precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the control systems for coarse and fine steering into a unified optical arrangement with integrated mounting structures. The first and second steering elements are mounted in relation to each other within the same housing, sharing common optical paths and support structures, which reduces the number of separate control systems and simplifies overall device complexity while maintaining precision steering capabilities.
3Ease of operation
If traditional steering elements are used, then beam steering is achieved, but spatial footprint increases
Solution Approach 1:
The patent implements a nested configuration where the second steering element (electro-optic or acousto-optic modulator) is positioned within or alongside the optical path of the first steering element (rotatable prism or mirror). This nesting allows the fine steering element to be accommodated within the spatial envelope of the coarse steering element, significantly reducing the overall spatial footprint of the pointing unit while maintaining full steering functionality.
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
This configuration reduces the spatial footprint and weight of the pointing unit while enabling precise beam steering over a wide range, enhancing the field-of-regard and reducing the need for additional relay optics.
Implementation Method 1
an electro-optic element having a refractive index that can be varied by varying an electric field applied thereto
Implementation Method 2
an optical element having a fixed refractive index or effective refractive index
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
A pointing unit (100) for use with a free space optical (FSO) communications terminal (105) is disclosed. The pointing unit (100) comprises an optical arrangement (101) of one or more optically transmissive steering elements (101a, 101b). The steering elements (101a, 101b) are arranged in an optical path of an incident beam (107) entering the optical arrangement (100), and the orientation of at least one element (101a, 101b), and the refractive index of at least one element (101a, 101b), are controllable to steer a beam (107b) towards a target (110).