Phase Sensitive Amplifier With Spectral Filtering For Noise Suppression
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Solution Overview
Problem
Conventional phase sensitive amplifiers used in optical communication systems suffer from noise degradation due to amplified spontaneous emission (ASE) and limited ability to amplify multiple wavelengths simultaneously, which degrades the signal-to-noise ratio (S/N) and restricts long-distance high-speed transmission.
Innovation Solution
A phase sensitive amplifier configuration using parametric amplification with an optical fiber amplifier to generate sufficient power for optical communication, while preventing ASE from being added to the signal light, allowing for simultaneous amplification of multiple wavelengths and suppressing noise through selective amplification of phase-correlated signal light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional laser amplifiers (fiber laser amplifier or semiconductor laser amplifier) are used to amplify signal light, then the signal light can be directly amplified without being limited by electric processing speed, but amplified spontaneous emission is generated and mixed with signal light, causing reduction of S/N ratio by at least 3dB
Solution Approach 1:
The invention segments the amplification process into two distinct stages: first, an optical amplifier amplifies the signal light along with generated ASE noise; second, a spectral filter separates the signal light from the ASE noise by filtering out specific wavelength bands. This segmentation allows the system to benefit from high-speed optical amplification while eliminating the harmful noise through wavelength-based separation.
Solution Approach 2:
The invention extracts the harmful amplified spontaneous emission noise from the amplified signal light using a spectral filter. The filter removes specific wavelength components corresponding to the ASE noise while preserving the signal light, thereby extracting only the useful signal component and discarding the harmful noise component.
2Device complexity
If conventional laser amplifiers are used, then the configuration is relatively simple, but they do not have a function to reshape a degraded pulse waveform of signal light
Solution Approach 1:
The invention introduces a spectral filter as an intermediary component between the optical amplifier and the output. This filter serves multiple functions: it removes ASE noise and simultaneously reshapes degraded pulse waveforms by selectively filtering frequency components. The filter acts as a mediator that improves signal quality without significantly increasing system complexity.
3Object-affected harmful factors
If phase sensitive amplifier is used to reshape signal light waveform and suppress spontaneous emission, then S/N ratio can be maintained, but the amplifier cannot amplify multiple wavelengths simultaneously and is limited in practical application
Solution Approach 1:
The invention creates a universal amplification system that can handle multiple wavelengths simultaneously by using an optical amplifier followed by a spectral filter. Unlike phase-sensitive amplifiers that are limited to specific wavelength operations, this configuration can amplify any wavelength that passes through the filter, making it adaptable to various wavelength divisions and practical communication systems.
4Power
If optical fiber amplifier is used to generate sufficient power for parametric amplification, then amplification can be achieved, but ASE is generated and mixed with signal light causing noise degradation
Solution Approach 1:
The invention extracts the harmful ASE noise generated by the optical fiber amplifier using a spectral filter positioned after the amplifier. The filter removes the noise components while preserving the amplified signal, thereby maintaining the power benefits of optical amplification while eliminating the associated noise degradation.
Solution Approach 2:
The spectral filter serves as an intermediary component that mediates between the high-power optical amplifier and the signal output. It allows the system to benefit from the amplifier's power generation capability while blocking the harmful ASE noise from reaching the output, effectively decoupling the power amplification function from the noise generation problem.
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 configuration achieves high-quality optical signal amplification with improved S/N ratio, enabling long-distance high-speed transmission at low power and reducing bit error rates, while suppressing phase chirp and ASE-induced noise.
Implementation Method 1
an amplifier configured to perform parametric amplification using a pump light and a nonlinear optical medium
Implementation Method 2
phase sensitive amplification based on optical parametric amplification
Data Source
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AI summary
It is an objective of the present invention to provide a phase sensitive amplifier that can be used for an optical communication and that can provide low-noise amplification. The phase sensitive amplifier according to the present invention is a phase sensitive amplifier that uses the optical mixing using a nonlinear optical effect to amplify the signal light. The phase sensitive amplifier according to the present invention includes: the first second-order nonlinear optical element (602-1); and the second second-order nonlinear optical element (602-2). The first second-order nonlinear optical element (602-1) causes the fundamental wave light (621) to generate second harmonic light (622) used as pump light. A filter (606-1) is provided that spectrally separates only the second harmonic light from the fundamental wave light and the second harmonic light. The second second-order nonlinear optical element (602-2) includes a multiplexer (606-2) to multiplex the signal light with the second harmonic light. The multiplexed signal light and second harmonic light are used subjected to parametric amplification. A filter (606-3) is provided that spectrally separates only the amplified signal light from the second harmonic light and the amplified signal light.