VCSEL Array Beam Steering for Satellite Optical Links

Solution Overview

Problem

Current optical communication systems for long-distance communication, particularly between satellites and ground terminals, face challenges with beam pointing accuracy, size, weight, and power consumption, especially in low-Earth orbit scenarios, where dynamic systems with moving parts are inefficient and prone to vibrations.

Innovation Solution

A novel optical data transmission system using laser arrays with a static lens system and VCSEL/Photodetector arrays for accurate pointing, acquisition, and tracking, which combines a lens system with a VCSEL/Photodetector Array in a compact and simple configuration, enabling finer steering and reducing reaction times and power requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If dynamic systems with moving parts (fast-steering mirrors, gimbals) are used for beam pointing, then beam pointing accuracy can be achieved, but the system size, weight, and power consumption increase significantly

Engineering Contradiction:

Improvebeam pointing accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical beam steering systems (fast-steering mirrors, gimbals) with an optical array system consisting of multiple laser elements and photodetectors. The mechanical moving parts are substituted with a static array where beam pointing is achieved by selectively activating different laser elements and processing signals from different photodetectors, eliminating the need for mechanical motion while maintaining pointing accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent divides the beam pointing function into multiple independent laser elements and photodetector elements arranged in arrays. Instead of using a single mechanical steering component, the system segments the functionality across multiple static elements, where each element contributes to the overall beam pointing capability through electronic control and signal processing.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If dynamic systems with moving parts are used for beam pointing, then beam pointing accuracy can be achieved, but the reaction time to pointing changes and vibrations is limited to nanosecond time scale

Engineering Contradiction:

Improvebeam pointing accuracyVSAvoidreaction time

Core Design Contradiction:

Measurement precisionVSSpeed

Solution Approach 1:

The patent replaces mechanical beam steering systems (fast-steering mirrors, gimbals) with an optical array system consisting of multiple laser elements and photodetectors. The mechanical moving parts are substituted with a static array where beam pointing is achieved by selectively activating different laser elements and processing signals from different photodetectors, eliminating the need for mechanical motion while maintaining pointing accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If high-powered lasers are used at ground terminal with modulating retro-reflector at satellite, then communication can be achieved, but backscatter becomes a limiting factor and thermal loads increase

Engineering Contradiction:

Improvecommunication capabilityVSAvoidbackscatter

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent divides the beam pointing function into multiple independent laser elements and photodetector elements arranged in arrays. Instead of using a single mechanical steering component, the system segments the functionality across multiple static elements, where each element contributes to the overall beam pointing capability through electronic control and signal processing.

Inventive Principle:

Principle #1Segmentation

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 system achieves diffraction-limited beam propagation, reduces backscatter, and allows for the use of low-power lasers, improving communication efficiency and reducing thermal loads, while being applicable to both low-Earth orbit and deep space optical communications.

Implementation Method 1

The novel arrangement achieves diffraction-limited beam propagation

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

VCSEL/Photodetector Array

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 3

combines a lens system and a VCSEL/Photodetector Array

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS11159247B1Optical communication system and method using laser arrays

Publication Date: 2021.10.26 UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR NAT AERONAUTICS & SPACE ADMINISTRATION

AI summary

A method and system for optical communication with between a device and a remote station include passing light incoming from the remote station and outgoing to the remote station through a lens system and an aperture of the device, for example the lens system comprising a Plössl lens or a double-Gauss lens. The method and device include receiving the incoming light at an optoelectronic assembly that has an array of VCSELs, an array of microlenses, and a plurality of photodetectors configured to generate an output signal in response to detected light. The VCSELs may be arranged in clusters for simultaneous emission, and multiple clusters may also be activated for simultaneous emission.