Optical Frequency Synthesizer Using Femtosecond Laser Injection Locking

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Solution Overview

Problem

Current optical frequency synthesizers using femtosecond lasers are complex and struggle to select a single mode or scan frequencies effectively, limiting the precision and simplicity of optical frequency measurement in optical communication systems.

Innovation Solution

An optical frequency synthesizer using femtosecond laser optical injection locking, where a mode-locked femtosecond laser is used as a master laser to inject light into a diode laser, achieving single-mode phase-locking and allowing for the adjustment of optical frequencies and repetition rates, enabling precise scanning of optical frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If femtosecond laser optical frequency comb is used for optical frequency measurement, then measurement precision is improved, but device complexity increases and single-mode selection becomes difficult

Engineering Contradiction:

Improveoptical frequency measurement precisionVSAvoidoptical frequency synthesizer complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts a single desired mode from the femtosecond laser optical frequency comb by using optical injection locking. The slave diode laser is locked to only one specific mode of the master femtosecond laser, effectively separating the desired single-mode output from the multi-mode comb structure. This allows precise optical frequency measurement while simplifying the system by eliminating the need for complex mode selection mechanisms.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a slave diode laser as an intermediary device between the femtosecond laser comb and the measurement system. This intermediary laser acts as a bridge that converts the multi-mode comb output into a stable single-mode output through optical injection locking, thereby simplifying the overall system complexity while maintaining high measurement precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If femtosecond laser comb is used, then optical frequency standard precision is improved, but frequency scanning capability deteriorates

Engineering Contradiction:

Improveoptical frequency standard precisionVSAvoidfrequency scanning capability

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent makes the optical frequency synthesizer dynamic by enabling continuous tuning of the slave diode laser frequency through current injection. This allows the locked frequency to be scanned across different optical frequencies while maintaining the precision benefits of optical injection locking, thus improving ease of operation without sacrificing measurement precision.

Inventive Principle:

Principle #15Dynamics

3Manufacturing precision

If optical injection locking is applied, then single-mode laser output is achieved, but system complexity increases

Engineering Contradiction:

Improvesingle-mode laser output qualityVSAvoidoptical injection locking system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the master femtosecond laser and slave diode laser into a unified optical injection locking system. By combining these two laser sources with a simple optical coupling mechanism, the system achieves high single-mode output quality without requiring complex additional components. The merging of the two laser systems allows the slave laser to inherit the stability and precision of the master laser while maintaining operational simplicity.

Inventive Principle:

Principle #5Merging (Combining)

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 simplifies the process of obtaining single-mode laser light and allows for precise scanning of optical frequencies, enhancing the precision and efficiency of optical frequency measurement beyond existing technologies.

Implementation Method 1

Optical injection locking is a method of locking the phase of a slave laser, having a wide frequency bandwidth and inferior spectrum characteristics, to the phase of a master laser, having a narrow frequency bandwidth and excellent spectrum characteristics, without requiring an electronic device.

Methodology Applied

Scientific EffectOptical injection locking:

Data Source

PatentUS7953131B2Frequency synthesizer and frequency synthesizing method using optical injection locking

Publication Date: 2011.05.31 KOREA RES INST OF STANDARDS & SCI

AI summary

The present invention relates to an optical frequency synthesizer and an optical frequency synthesizing method using femtosecond laser optical injection locking, which inject a femtosecond laser optical frequency comb into a diode laser, thus obtaining single-mode laser light, phase-locked to only a single mode in the optical frequency comb, and which change the optical frequency and interval, that is, the repetition rate, of a femtosecond laser, together with the frequency of a semiconductor laser, thus scanning optical frequencies while realizing a single desired optical frequency. The optical frequency synthesizer using femtosecond laser optical injection locking, includes a mode-locked femtosecond laser (110), which is a master laser, and a diode laser (120), which is a slave laser and into which laser light emitted from the femtosecond laser is injected.