Broad Spectrum Optical Source for Free Space Communication
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Solution Overview
Problem
Conventional microwave and RF communication systems face challenges with limited spectrum allocation and interference from atmospheric turbulence in free-space optical communications, which complicates the direct detection of intensity-modulated optical signals.
Innovation Solution
A free space optical communication system using a broad spectrum light source with an optical component that introduces intentional time delays to different sections of the optical beam, creating non-coherent beams that can be detected using a single transmitter and modulator, eliminating the need for multiple transmitters and simplifying the system design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional microwave and RF communication systems are used, then communication can be established, but the spectrum allocation is highly constrained and bandwidth is limited
Solution Approach 1:
The patent transitions from microwave/RF frequency parameters to optical frequency parameters, utilizing the vast optical spectrum (greater than 100 THz) to achieve unlimited bandwidth. This parameter change from radio frequency to optical frequency resolves the bandwidth limitation while avoiding spectrum allocation constraints through the use of free-space optical communication
2Adaptability or versatility
If free-space optical communication is used, then unlimited bandwidth is achieved, but atmospheric turbulence interferes with optical signals
Solution Approach 1:
The patent segments the optical beam into multiple independent beams that traverse different atmospheric paths. By dividing the single beam into multiple beams, the system reduces the impact of atmospheric turbulence on any single beam, as turbulence affects each beam path independently. This segmentation approach allows the receiver to combine signals from multiple beams, thereby mitigating turbulence interference while maintaining the unlimited bandwidth advantage of optical communication
3Reliability
If multiple transmitters are used to overcome atmospheric turbulence, then signal reliability is improved, but system complexity and operational overhead increase
Solution Approach 1:
The patent merges the functions of multiple transmitters and modulators into a single transmitter by using a spatial light modulator to encode multiple independent beam patterns from one optical source. This combining approach achieves the same diversity benefit as multiple transmitters while reducing system complexity and operational overhead, as a single transmitter with spatial modulation capability can generate multiple independent beams that are less susceptible to atmospheric turbulence
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 approach enhances the detection capabilities of direct detection systems, reduces complexity and operational overhead, and improves signal-to-noise ratio by summing non-interfering, incoherent signals, thus overcoming atmospheric interference and spectrum allocation constraints.
Implementation Method 1
The plurality of sections of the optical components are formed to introduce optical path differences into portions of the optical beam that impinge on the optical component such that each section introduces a delay into a corresponding portion of the optical beam that is different from a delay introduced into other portions of the optical beam by other sections of the optical component
Implementation Method 2
The delays introduced by the plurality of sections cause each portion of the optical beam that impinges on a corresponding section of the optical component to lack coherence with other portions of the optical beam that impinge on other sections of the optical component
Implementation Method 3
The receiver includes a photodetector to sense an intensity of the received portions of the optical beam, and enables detection of the received optical beam using a direct detection technique
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
Optical systems and methods for transmission of multiple beams and direct detection of those beams are described. One transmitter for use in a free space optical communication system includes a broad spectrum light source and an optical component including a plurality of sections positioned to receive an optical beam produced by the broad spectrum light source. The sections of the optical component are formed to introduce optical path differences into portions of the optical beam that impinge on the optical component such that each section introduces a delay into a corresponding portion of the optical beam. The introduced delays cause each portion of the optical beam to lack coherence with other portions of the optical beam. A direct detection receiver detects the intensity of the aggregate beams and produces a signal with improved signal-to-noise ratio. The disclosed technology can be used with modulated optical beams such as intensity modulated beams.