Two-Carrier Optical Transport System with Phase-Sensitive Amplification
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Solution Overview
Problem
Conventional optical transport systems face limitations in information-transmission capacity due to noise and signal distortion, particularly in optical phase-sensitive amplification processes.
Innovation Solution
The implementation of an optical transport system utilizing phase-sensitive amplifiers (PSAs) that generate and amplify a two-carrier signal through nonlinear optical processes, enabling phase-sensitive amplification and signal-to-noise ratio gain, thereby increasing information-transmission capacity by up to 2 bits per second per Hertz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional optical transport systems are used, then system simplicity is maintained, but information-transmission capacity is limited due to noise and signal distortion
Solution Approach 1:
The system segments the optical signal into two separate carrier waves (first carrier at frequency f1 and second carrier at frequency f2) that are phase-locked to each other. This segmentation allows independent optimization of each carrier's transmission while maintaining overall system capacity, enabling the system to overcome noise and distortion limitations without requiring complete system redesign
Solution Approach 2:
The patent introduces a phase dimension by implementing phase-locked dual carriers, where the phase relationship between the two carriers is maintained and utilized for signal transmission. This adds a new degree of freedom to the transmission system, allowing for enhanced information capacity beyond what conventional single-carrier systems can achieve, while the phase-locking mechanism keeps the complexity manageable
2Reliability
If phase-sensitive amplification is applied, then signal-to-noise ratio improves, but system complexity increases due to nonlinear optical processes
Solution Approach 1:
The system creates a copy of the input signal by generating a second carrier wave that is phase-locked to the first carrier. This copied signal undergoes phase-sensitive amplification where the nonlinear optical process amplifies both carriers simultaneously, maintaining their phase relationship. This copying approach enables the system to achieve noise reduction through amplification while keeping the optical process complexity contained within standard nonlinear optical components
Solution Approach 2:
The patent utilizes phase-sensitive amplification by changing the phase parameters of the optical signals through nonlinear optical processes. The amplifier modifies the phase relationship between the carriers and the pump signals, enabling noise figure of 0 dB theoretical performance. This parameter change approach allows for high reliability signal amplification using well-understood nonlinear optical physics rather than complex control systems
3Productivity
If two-carrier signals are transmitted, then information capacity increases by up to 2 bits per second per Hertz, but signal processing complexity increases
Solution Approach 1:
The system merges the detection of two separate carrier signals into a unified processing approach by maintaining their phase-locked relationship throughout transmission and reception. The receiver combines the information from both carriers through coherent detection, leveraging their correlated phase characteristics. This merging strategy doubles the information capacity (up to 2 bits per second per Hertz) while avoiding the need for completely separate detection systems for each carrier
Solution Approach 2:
The phase-locked dual carrier system incorporates feedback mechanisms where the phase relationship between carriers is continuously monitored and maintained. The receiver uses feedback information about the phase state to properly demodulate the signals, enabling accurate recovery of transmitted information. This feedback approach manages the processing complexity by providing reference information that simplifies the detection of modulated signals
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 effectively enhances information-transmission capacity by leveraging redundancies in the two-carrier signal, providing improved noise resistance and signal clarity through phase-sensitive amplification, outperforming conventional systems.
Implementation Method 1
a nonlinear optical device configured to optically mix, via a phase-conjugation (PC) process, the first modulated optical signal, a first optical-pump signal, and a second optical-pump signal to generate a second modulated optical signal
Implementation Method 2
an optical detector configured to generate a first measure and a second measure, said first measure being a measure of the first mixed signal and said second measure being a measure of the second mixed signal
Implementation Method 3
The PSAs employ a second nonlinear optical process to optically amplify the two-carrier signal in a phase-sensitive manner to counteract the attenuation imposed onto the two-carrier signal by lossy components of the optical link
Implementation Method 4
an optical modulator configured to modulate an optical carrier with data to generate a first modulated optical signal
Data Source
AI summary
In one embodiment, the optical transport system has an optical transmitter, an optical receiver, and one or more phase-sensitive amplifiers (PSAs) disposed within an optical link that connects the optical transmitter and receiver. The optical transmitter employs a first nonlinear optical process to generate a two-carrier signal in a manner that makes this signal suitable for phase-sensitive amplification. The PSAs employ a second nonlinear optical process to optically amplify the two-carrier signal in a phase-sensitive manner to counteract the attenuation imposed onto the two-carrier signal by lossy components of the optical link. The optical receiver employs a third nonlinear optical process in a manner that enables the receiver to beneficially use redundancies in the two-carrier signal, e.g., for an SNR gain. The optical transport system can advantageously be implemented to have better noise properties than a comparable conventional system, which enables a commensurate increase in the data-transport capacity.