Asymmetric Optical Circulator for Free-Space Signal Coupling
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Solution Overview
Problem
Existing free space optical communications systems face challenges in efficiently coupling optical signals due to the asymmetry introduced by atmospheric conditions and the need for precise alignment of optical circulators, which are not suitable for multimode fibers.
Innovation Solution
An optical circulator that couples a single mode fiber to a multimode fiber, allowing for efficient transmission and reception of optical signals without degrading the mode structure, and an adaptive optics system for wavefront correction to mitigate aberrations, enabling better alignment and signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a symmetric optical circulator with single mode fibers is used, then the device is suitable for fiber optic communications networks, but it cannot efficiently couple the distorted multimode optical beam received from free space back into a single mode fiber
Solution Approach 1:
The patent applies asymmetry by designing an asymmetric optical circulator where port 1 uses a single mode fiber for transmitting the outgoing optical beam, while port 3 uses a multimode fiber for receiving the incoming distorted optical beam from free space. This asymmetric configuration allows the circulator to handle both single mode and multimode beams appropriately, resolving the contradiction between coupling efficiency and mode compatibility.
2Adaptability or versatility
If port 2 of the optical circulator couples directly to the rest of the telescope, then the outgoing and incoming optical beams can share the same free-space optical path, but precise alignment of the optical circulator with the telescope is required
Solution Approach 1:
The multimode fiber at port 3 acts as an intermediary between the telescope's free-space optical path and the single mode fiber at port 1. This intermediary allows the optical circulator to be coupled to the telescope without requiring precise alignment, as the multimode fiber can accommodate the distorted beam from free space and transfer it to the single mode fiber for further processing.
3Reliability
If atmospheric effects and overfilling of the receive aperture occur, then the received light becomes distorted and cannot be efficiently coupled into a single mode fiber, but using a multimode fiber degrades the mode structure
Solution Approach 1:
The patent segments the optical signal path into two distinct segments: the incoming distorted beam from free space is coupled into the multimode fiber at port 3, while the outgoing beam from the single mode fiber at port 1 is transmitted through the telescope. This segmentation allows each fiber type to be optimized for its specific function without compromising the other.
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 solution enables efficient coupling of optical signals in free space optical communications systems, improving signal quality and reducing the need for precise alignment, while maintaining high performance for Gigabit Ethernet transmission.
Implementation Method 1
an optical circulator coupling optical fibers of dissimilar modes. In one embodiment, an optical circulator couples a single mode first fiber to a multimode second fiber
Implementation Method 2
an adaptive optics system operably coupled to the telescope for correcting a wavefront of the transmitted and/or received light
Data Source
AI summary
An optical circulator couples optical fibers of dissimilar modes. In one embodiment, an optical circulator couples a single mode first fiber to a multimode second fiber, which is used as an optical input to a telescope. The multimode fiber does not significantly degrade the mode structure of the light form the single mode fiber. In the reverse direction, light received by the telescope is coupled into the multimode second fiber, which the circulator couples to a multimode third fiber.