Coherent Gated Receiver for OCDMA Signal Sensitivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing coherent detection methods for Optical Code Division Multiple Access (OCDMA) signals are complex and do not adequately reduce receiver complexity while increasing sensitivity, leading to limitations in the number of users and data rates that can be supported in optical communication systems.
Innovation Solution
A coherent gated receiver design that includes a decoder, demultiplexer, phase mask, multiplexer, mode locked local oscillator laser, and balanced detectors to spatially distribute and combine optical signals, effectively rejecting other coded signals and enhancing signal recovery with reduced complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional coherent detection methods are used for OCDMA signals, then detection sensitivity can be maintained, but receiver complexity increases significantly
Solution Approach 1:
The patent extracts and removes the optical time gate component from the conventional coherent detection system. By eliminating this complex component while maintaining the core coherent detection functionality through the phase mask and code-matched filtering, the receiver achieves reduced complexity while preserving detection sensitivity for OCDMA signals.
Solution Approach 2:
The phase mask in the patent serves multiple functions: it performs code-matched filtering, provides temporal gating functionality, and enables coherent detection all in a single component. This multi-functionality eliminates the need for separate optical time gates and reduces the overall receiver complexity while maintaining detection performance.
2Productivity
If the number of users and data rates are increased in optical communication systems, then system capacity improves, but signal-to-noise ratio deteriorates
Solution Approach 1:
The patent utilizes code-matched filtering through phase masks that are specifically designed for each user's code sequence. By changing the filtering parameters to match the specific code, the system can extract the desired signal while rejecting multi-user interference and noise, thereby maintaining signal-to-noise ratio even as system capacity increases.
Solution Approach 2:
The coherent detection process inherently provides feedback through the local oscillator that is phase-locked to the incoming signal. This feedback mechanism allows the receiver to continuously adjust and maintain optimal detection conditions, improving signal-to-noise ratio performance in high-capacity multi-user environments.
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 proposed solution reduces receiver complexity and increases sensitivity, allowing for efficient rejection of other coded signals and improved signal recovery, thereby supporting a higher number of users and data rates in optical communication systems without the need for additional components like optical time gates.
Implementation Method 1
a mode locked local oscillator laser, and a balanced detector
Implementation Method 2
a combiner coupled to the laser source and the decoder operable to combine the decoded optical signal and the pulse signal
Implementation Method 3
a balanced detector operable to detect an output from the combiner
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention is directed to a coherent gated receiver. The receiver includes a decoder operable to receive an optical signal and generate a decoded optical signal, the decoder comprises a demultiplexer operable to spatially distribute the optical signal, a phase mask operable to decode the spatially distributed optical signal, and a multiplexer operable to combine the decoded spatially distributed optical signal. The receiver also includes a laser source operable to provide a pulse signal, a combiner coupled to the laser source and the decoder operable to combine the decoded optical signal and the pulse signal, and a detector operable to detect an output from the combiner.