Parametric Mixer Frequency Comb Generation

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Solution Overview

Problem

Conventional frequency comb generation techniques, particularly those using mode-locked lasers, face limitations due to cavity stability issues, leading to increased phase noise and reduced accuracy, which degrades the coherence and utility of the frequency comb in applications like communication and spectroscopy.

Innovation Solution

The use of a parametric mixer seeded by phase-correlated optical waves with different carrier frequencies to generate multiple optical tones with controlled spectral linewidth, maintaining coherence across the frequency comb range, thereby overcoming the limitations of mode-locked laser sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If mode-locked lasers are used for frequency comb generation, then spectral bandwidth can be achieved, but cavity stability issues cause increased phase noise and reduced coherence

Engineering Contradiction:

Improvespectral bandwidthVSAvoidcoherence

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent divides the frequency comb generation process into two independent stages: (1) a mode-locked laser generates a broad spectral bandwidth, and (2) a separate parametric mixer processes this spectrum to generate the frequency comb. This segmentation isolates the bandwidth generation from the coherence-critical mixing process, allowing each stage to be optimized independently without compromising overall system performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a parametric mixer as an intermediary device between the mode-locked laser and the final frequency comb output. This intermediary processes the broad spectrum from the MLL while maintaining coherence through phase-correlated mixing, effectively decoupling the bandwidth provision from the coherence maintenance functions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If conventional frequency comb techniques are used, then frequency comb generation is achieved, but residual frequency noise increases and accuracy decreases

Engineering Contradiction:

Improvefrequency comb generationVSAvoidfrequency accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent replaces the conventional mechanical cavity-based frequency reference system with an optical parametric mixing system. This substitution eliminates the mechanical stability limitations and residual frequency noise inherent in traditional cavities, achieving superior frequency accuracy while maintaining comb generation capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental operating parameters of frequency comb generation by using phase-correlated parametric mixing instead of cavity-based mode locking. This parameter change transforms the noise characteristics and frequency stability, reducing residual frequency noise while maintaining the frequency comb structure.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If parametric mixer is seeded by phase-correlated optical waves, then spectral linewidth is controlled and coherence is maintained, but device complexity increases

Engineering Contradiction:

ImprovecoherenceVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary phase-correlation processing to the optical waves before they enter the parametric mixer. By pre-establishing the phase relationships through optical modulation or injection locking, the system simplifies the mixing process while maintaining coherence, reducing the complexity burden on the parametric mixer itself.

Inventive Principle:

Principle #10Preliminary action

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 reduces residual frequency noise, improves signal-to-noise ratio, and enhances the frequency stability of optical sources, increasing the sensitivity and operational range of spectroscopy apparatus and coherent communication systems.

Implementation Method 1

a parametric mixer seeded by phase-correlated optical waves with different carrier frequencies to generate multiple optical tones

Methodology Applied

Scientific EffectParametric mixing:

Implementation Method 2

mixing the at least two second optical waves to generate a plurality of third optical waves

Methodology Applied

Scientific EffectNonlinear optical mixing:

Implementation Method 3

at least one section of the optical medium has a third-order nonlinear optical response, and has a nonlinear coefficient of at least 2 (W·km)−1

Methodology Applied

Scientific EffectThird-order nonlinear optical effect:

Data Source

PatentUS9810967B2Method and apparatus for generation of coherent frequency combs

Publication Date: 2017.11.07 ROSHMERE INC

AI summary

Embodiments of the invention provide apparatuses and methods for generating frequency combs. A non-linear optical medium may generate new optical waves centered at frequencies differing from the input waves, while retaining the input wave properties. In the case when a parametric mixer is used to generate frequency combs with small frequency pitch, the phase correlation of the input (seed) waves can be achieved by an electro-optical modulator and a single master laser. In the case when a frequency comb possessing a frequency pitch that is larger than frequency modulation that can be affected by an electro-optic modulator, the phase correlation of the input (seed) waves is achieved by combined use of an electro-optical modulator and injection locking to a single or multiple slave lasers.