Hybrid Optical Phase Squeezer for Low-Power Signal Regeneration

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Solution Overview

Problem

Current optical phase quantization techniques require highly nonlinear optical elements and high power pump lights, making them unsuitable for integration and practical use, especially in achieving a gain extinction ratio (GER) of 25 dB or higher.

Innovation Solution

The method employs a hybrid optical phase squeezer (HOPS) using four-wave mixing without optical parametric gain, allowing for phase quantization with a low nonlinear optical element and achieving GERs exceeding 30 dB by coherently adding phase conjugate light and phase harmonic light, with power modulation to adjust the mixing ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a phase sensitive optical amplifier (PSA) is used to perform optical phase quantization, then the phase regeneration function is achieved, but highly nonlinear optical elements and high power pump light are required making integration difficult

Engineering Contradiction:
Improvephase regeneration functionVSAvoidintegration difficulty
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention changes the operating parameters by using four-wave mixing without optical parametric gain, operating in a different regime from conventional PSA. This allows phase quantization using low nonlinearity optical elements with standard pump powers, enabling integration while maintaining phase regeneration functionality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention substitutes the conventional PSA mechanism (relying on optical parametric gain in highly nonlinear media) with a four-wave mixing approach that does not require optical parametric gain. This replacement eliminates the need for highly nonlinear optical elements and high power pumps, making the system integrable

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a phase sensitive optical amplifier (PSA) is used to achieve high gain extinction ratio (GER), then phase quantization performance is improved, but high optical parametric gain is required which demands high power pump light

Engineering Contradiction:
Improvegain extinction ratioVSAvoidpump light power
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The invention changes the operational parameters by eliminating the requirement for optical parametric gain. By using four-wave mixing without parametric gain, the system achieves high GER (exceeding 30 dB) with low pump power, reversing the conventional relationship where high GER required high power

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention converts the absence of optical parametric gain (which would normally be considered a limitation) into a benefit. By operating without parametric gain, the system achieves high GER with low pump power, turning what could be seen as a deficiency into the key advantage enabling low-power operation

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If highly nonlinear optical elements are used to achieve sufficient optical parametric gain, then the required GER is achieved, but the breakdown threshold is exceeded making the system unreliable

Engineering Contradiction:
Improvegain extinction ratioVSAvoidbreakdown threshold margin
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The invention changes the fundamental operating parameters by eliminating optical parametric gain requirements. This allows operation with low nonlinearity optical elements at low pump powers, achieving high GER while remaining well below breakdown thresholds, thus ensuring system reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention substitutes the high-stress regime of optical parametric gain with a low-stress four-wave mixing regime. This replacement eliminates the need to operate near breakdown thresholds, making the system reliable while maintaining high GER performance

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enables efficient phase quantization with reduced power requirements, facilitating integration and achieving high GERs, making it suitable for practical applications in optical communication systems.

Implementation Method 1

perform operations such as phase conjugate light generation and phase harmonic light generation by four-wave mixing

Methodology Applied
Scientific EffectFour-wave mixing:

Implementation Method 2

a technique of quantizing a phase of light by utilizing an optical parametric process which is one of nonlinear optical phenomena

Methodology Applied
Scientific EffectOptical parametric process:

Data Source

PatentEP3115840B1Optical phase regeneration method and device
Publication Date: 2020.05.06 NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE & TECHNOLOGY
  • EP3115840B1 patent drawingFigure 1(a)~1(b)
  • EP3115840B1 patent drawingFigure 2~3
  • EP3115840B1 patent drawingFigure 4

AI summary

In a signal regeneration device in which recovery of a signal quality which has been degraded during transmission in optical communication and extension of a transmission distance are achieved, the most representative method of quantizing an optical phase is a phase sensitive amplifier (PSA) and a technique that utilizes an optical parametric process through use of a highly nonlinear optical medium, but there is a demand for a technique of quantizing an optical phase which is not accompanied with an optical parametric gain, has small-sized elements, is easily integrated, and does not require high power pump light By a technique of a hybrid optical phase squeezer (HOPS), when a phase of input light is quantized to M levels (M > 2), phase conjugate light of the input light and (M-1)th phase harmonic light of the input light are subjected to power modulation to be coherently added, so that quantization of the optical phase is performed through use of a simple four-wave mixing (FWM) that is not accompanied with the optical parametric gain and a general optical amplifier by using a general nonlinear optical medium such as silicon, and accordingly, a GER of equal to or higher than 30 dB can be obtained, even if a nonlinear optical element having a low nonlinearity is used.