Optical Communication Terminal Full Duplex Switching
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Solution Overview
Problem
Existing aerial communication networks face challenges in establishing reliable and efficient full duplex communication links between balloons in a mesh network, particularly in switching between different communication modes to facilitate bi-directional data transfer over free space optical links.
Innovation Solution
The implementation of an optical communication terminal with a dichroic beam splitter and a steering mirror that dynamically adjusts to align light emitters and detectors for different wavelengths, allowing balloons to switch between two complementary modes of operation to establish full duplex communication links, enabling simultaneous data transmission and reception using distinct wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single primary aperture is shared for both transmission and reception, then device complexity is reduced, but it becomes difficult to separate transmitted and received light paths for full duplex communication
Solution Approach 1:
The patent segments the optical path by wavelength using a dichroic beam splitter. The beam splitter divides the single aperture's optical path into separate channels for different wavelengths, allowing transmitted light at wavelength 1 and received light at wavelength 2 to be separated and directed to different detectors, thereby enabling full duplex communication through a single shared aperture.
Solution Approach 2:
The dichroic beam splitter acts as an intermediary optical element that mediates between the single primary aperture and the multiple light sources/detectors. It selectively transmits and reflects different wavelengths to create separate optical paths, enabling the system to achieve full duplex functionality without requiring separate physical apertures for transmission and reception.
2Reliability
If beam steering mirrors are used to align optical paths, then communication reliability is improved, but the system becomes more complex and requires precise adjustment
Solution Approach 1:
The steering mirror serves multiple functions: it directs transmitted light from the primary aperture toward the remote terminal, directs received light from the remote terminal to the appropriate detector, and can be adjusted to switch between different communication modes (Mode A and Mode B). This multi-functionality reduces the need for separate alignment components for each function.
Solution Approach 2:
The steering mirror is designed to be dynamically adjustable, allowing the system to switch between different operational modes by changing the mirror's orientation. This dynamic adjustment capability enables the single terminal to adapt to different communication scenarios and maintain reliable alignment without requiring multiple fixed mirrors for each function.
3Productivity
If wavelength division multiplexing is used for full duplex communication, then communication capacity is increased, but the optical path separation becomes more challenging
Solution Approach 1:
The dichroic beam splitter applies local quality differentiation by having different optical properties at different locations or for different wavelengths. It is designed to transmit wavelength 1 while reflecting wavelength 2, creating wavelength-specific optical paths within the single aperture system. This local quality approach enables automatic wavelength-based separation without complex mechanical switching.
Solution Approach 2:
The system utilizes parameter changes in the light itself (wavelength) to achieve path separation. By assigning different wavelengths to transmitted and received signals, the dichroic beam splitter can automatically separate the optical paths based on this parameter difference, enabling full duplex communication without requiring complex temporal or spatial multiplexing mechanisms.
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 solution enables efficient bi-directional communication between balloons by dynamically switching between communication modes, ensuring reliable and high-capacity data transfer in a mesh network, even as balloon positions change, thereby addressing the limitations of existing technologies.
Implementation Method 1
a beam splitter configured to transmit light of a first wavelength and to reflect light of a second wavelength
Implementation Method 2
The steering mirror and the beam splitter can be arranged such that, while the steering mirror has a first orientation, (i) light of the first wavelength that is emitted from the first emission location is directed for transmission toward a remote terminal
Implementation Method 3
a laser light source configured to emit light of the first wavelength from a first emission location and to emit light of the second wavelength from a second emission location
Implementation Method 4
one or more detectors configured to detect, at a first detection location, light of the first wavelength, and to detect, at a second detection location, light of the second wavelength
Data Source
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AI summary
An optical communication terminal is configured to operate in two different complementary modes of full duplex communication. In one mode, the terminal transmits light having a first wavelength and receives light having a second wavelength along a common free space optical path. In the other mode, the terminal transmits light having the second wavelength and receives light having the first wavelength. The terminal includes a steering mirror that directs light to and from a dichroic element that creates different optical paths depending on wavelength, and also includes spatially separated emitters and detectors for the two wavelengths. A first complementary emitter/detector pair is used in one mode, and a second pair is used for the other mode. The optical components are arranged such that adjusting an orientation of the steering mirror aligns the terminal to communication over a given free space optical link using either the first or second complementary pair.