Acousto-Optic Wavelength Conversion for Multi-Wavelength Quasi-Phase Matching

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Solution Overview

Problem

Conventional wavelength converting elements face difficulties in reliably and efficiently generating non-linear optical effects for input lights with wavelengths differing from the specific wavelength designed for the polarity inversion period of the polarity inverting structure.

Innovation Solution

A wavelength conversion apparatus that includes a light source section with multiple light sources, a direction changing section using an acousto-optic element to adjust the incident angle of input light relative to the polarity inverting structure, allowing quasi-phase matching for various input wavelengths, thereby efficiently generating second harmonic components across a broader wavelength range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the polarity inversion period is designed to correspond to a specific wavelength, then the non-linear optical effect is efficiently generated for that specific wavelength, but it becomes difficult to reliably and efficiently create the non-linear optical effect for input lights with wavelengths differing from the specific wavelength

Engineering Contradiction:
Improvereliability of non-linear optical effect generationVSAvoidwavelength range coverage
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies the dynamics principle by making the incident angle of input light adjustable rather than fixed. By changing the incident angle dynamically, the system can adapt to different input wavelengths and maintain reliable non-linear optical effect generation across a broad wavelength range, resolving the contradiction between reliability for specific wavelengths and adaptability for multiple wavelengths

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs parameter changes by varying the incident angle parameter of input light relative to the polarity inverting structure. This parameter adjustment allows the system to match different input wavelengths with the appropriate incident angle, enabling reliable wavelength conversion across a wide spectral range while maintaining the fixed polarity inversion period structure

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If a fixed polarity inversion period structure is used, then the device structure is simple and manufacturing is easier, but the system cannot efficiently handle multiple input wavelengths

Engineering Contradiction:
Improveease of manufacturing wavelength converting elementVSAvoidcapability to handle multiple wavelengths
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

Instead of modifying the complex polarity inverting structure to handle multiple wavelengths, the patent introduces a dynamic incident angle adjustment mechanism. This keeps the manufacturing process simple while adding adaptability through operational flexibility, allowing the same structure to efficiently convert multiple wavelengths by adjusting the input angle

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces an intermediary element (the adjustable incident angle mechanism) between the input light and the polarity inverting structure. This intermediary allows wavelength adaptation without modifying the polarity structure itself, maintaining ease of manufacture while achieving multi-wavelength capability

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The apparatus enables the creation of non-linear optical effects with high efficiency for multiple input lights with different wavelengths, improving reliability and stability by adjusting the incident angle to match the polarity inversion period, thus overcoming the limitations of conventional systems.

Implementation Method 1

a direction changing section (230) that changes the direction of each input light to have a progression direction that quasi-phase matches the wavelength converting section (220), in response to changes in frequency of an acoustic wave applied to the acousto-optic element

Methodology Applied
Scientific EffectAcousto-optic effect: Acousto-optic Effect

Implementation Method 2

a wavelength converting section (220) that converts the wavelength of each input light in response to the direction changing section (230) changing the direction of each input light... creates a non-linear optical effect

Methodology Applied
Scientific EffectSecond harmonic generation: Second Harmonic Generation

Implementation Method 3

a polarity inverting structure (222) having a polarity inversion period for converting the wavelength of each input light... inputs light perpendicular to a direction in which the polarity of the polarity inverting structure inverts, and realizes a non-linear optical effect

Methodology Applied
Scientific EffectQuasi-phase matching:

Data Source

PatentEP2626742B1Wavelength converting apparatus, light source apparatus and wavelength converting method
Publication Date: 2015.05.06 ADVANTEST CORP
  • EP2626742B1 patent drawingFigure 1
  • EP2626742B1 patent drawingFigure 2
  • EP2626742B1 patent drawingFigure 3

AI summary

In order to create a stable non-linear optical effect with high efficiency for a plurality of input lights having different wavelengths, according to a first aspect of the present invention, provided is a wavelength conversion apparatus (200) comprising an input section (210) into which input light is input; a wavelength converting section (220) that includes a polarity inverting structure (222) whose polarity inverts periodically and that, in response to the input of light having a wavelength corresponding to the period with which the polarity inverts, converts the wavelength of the light; and a direction changing section (230) that changes a progression direction in which the input light passes through the polarity inverting structure (222),dependent on the wavelength of the input light, without changing relative positions of the input section (210) and the polarity inverting structure (222). Also provided are a light source apparatus (100) and a wavelength converting method.