Acousto-Optical Laser Wavelength Tuner

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Solution Overview

Problem

Existing laser systems are not easily adjustable to change lasing wavelengths once built, requiring rebuilding or unstable alignment methods like diffractive optics, which introduce substantial losses and alignment issues.

Innovation Solution

A wavelength-adjustable laser system using a single acousto-optical modulator and pair of optical reflectors within the laser cavity, allowing wavelength selection through adjustable radio-frequency signals to diffract and reflect specific wavelengths, maintaining stability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If diffractive optics such as diffraction gratings are used to select wavelength, then wavelength selection capability is improved, but alignment difficulty and system stability deteriorate

Engineering Contradiction:

Improvewavelength selection capabilityVSAvoidalignment difficulty

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent replaces mechanical diffraction grating systems with an acousto-optical modulator that uses acoustic waves to create diffraction patterns. This substitution eliminates the need for mechanical rotation and physical alignment of gratings, while achieving the same wavelength selection function through electronic control of acoustic frequency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an acousto-optical modulator as an intermediary device between the gain medium and the optical cavity mirrors. This modulator uses acoustic waves as a mediator to diffract specific wavelengths into the optical cavity, providing precise wavelength selection without requiring mechanical alignment of traditional diffraction gratings.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If diffractive optics are used to tune wavelength by physical movement, then wavelength adjustability is improved, but system stability deteriorates

Engineering Contradiction:

Improvewavelength adjustabilityVSAvoidsystem stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces mechanical movement of diffraction gratings with acoustic wave modulation in an acousto-optical modulator. Wavelength tuning is achieved by electronically adjusting the acoustic frequency rather than physically moving components, thereby maintaining system stability while enabling wavelength adjustability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements dynamic wavelength tuning through acoustic frequency modulation rather than static mechanical positioning. The acousto-optical modulator allows rapid, electronic adjustment of the diffracted wavelength by changing the acoustic drive frequency, providing dynamic control without mechanical movement.

Inventive Principle:

Principle #15Dynamics

3Measurement precision

If dielectrically coated mirrors are used for wavelength selection, then wavelength specificity is improved, but reconfigurability deteriorates

Engineering Contradiction:

Improvewavelength specificityVSAvoidreconfigurability

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent places an acousto-optical modulator as an intermediary between the gain medium and the fixed dielectric mirrors. This modulator dynamically selects which wavelengths are diffracted into the cavity for amplification, while the mirrors themselves remain fixed with their wavelength-specific coatings intact, thus maintaining both wavelength specificity and reconfigurability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the operational parameter from fixed mirror coating selection to dynamic acoustic frequency modulation. By varying the acoustic frequency in the modulator, different wavelengths are selectively diffracted into the cavity, enabling reconfigurability while the dielectric mirrors maintain their fixed wavelength-specific reflective properties.

Inventive Principle:

Principle #35Parameter changes

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

Enables stable and efficient selection of different wavelengths without physical reconfiguration, minimizing losses at undesired wavelengths and maximizing gain at the desired wavelength, with no need for rebuilding the laser cavity.

Implementation Method 1

an acousto-optical modulator located between the gain medium and the first optical reflector such that the acousto-optical modulator diffracts a portion of the laser beam into a plurality of diffracted laser beams wherein each diffracted laser beam diffracts at a different angle

Methodology Applied

Scientific EffectAcousto-optic effect: Acousto-optic Effect

Data Source

PatentUS7564880B2Laser intra-cavity electronic wavelength tuner

Publication Date: 2009.07.21 THE BOEING CO

AI summary

An apparatus for adjusting the wavelength of a laser capable of lasing at multiple wavelengths by using a single acousto-optical modulator and a pair of optical reflectors inside a laser cavity. By adjusting the frequency and amplitude of the radio-frequency source to the acousto-optical modulator, undesired wavelengths are suppressed in the laser cavity, leaving appreciable gain only at the desired wavelength.