QPM Wavelength Conversion Element for Pulse Ripple Suppression
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Solution Overview
Problem
Conventional wavelength conversion elements with chirp structures face significant fluctuations in wavelength conversion efficiency and pulse waveform ripples due to precision requirements in controlling the dimensions and positions of polarization regions, which are challenging to achieve with current technology.
Innovation Solution
A wavelength conversion element with a QPM structure where the absolute value of the nonlinear optical coefficient is adjusted by shifting the positional coordinates of polarization regions in the light traveling direction, allowing for stepped changes in wavelength conversion efficiency without requiring high-precision control of region dimensions or positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the dimensions and positions of polarization regions are controlled at high precision to suppress wavelength conversion efficiency fluctuation, then the wavelength conversion efficiency stability is improved, but the manufacturing complexity and difficulty increase significantly
Solution Approach 1:
The patent changes the control parameter from dimensional precision (widths and positions of polarization regions) to a simpler parameter (voltage application conditions). By adjusting the voltage magnitude and duration during the polarization inversion process, the wavelengths of polarization regions can be controlled without requiring high-precision mechanical or geometric control, thus resolving the contradiction between efficiency stability and manufacturing complexity
Solution Approach 2:
The patent replaces the mechanical/geometric control system (precise positioning and dimension control of polarization regions) with an electrical control system (voltage application conditions). This substitution allows for easier and less complex control while achieving the same goal of suppressing wavelength conversion efficiency fluctuation and pulse waveform ripples
2Manufacturing precision
If the positions and dimensions of electrodes are controlled at high precision to achieve sufficient dimensional accuracy, then the wavelength conversion efficiency fluctuation is suppressed, but the manufacturing difficulty increases due to electron beam writing device resolution limits
Solution Approach 1:
The patent replaces the electron beam writing device (mechanical/pattern-based system) with a voltage application system (electrical field-based system). This substitution eliminates the resolution limits of electron beam writing devices, as voltage can be applied continuously and precisely without being constrained by physical writing head dimensions or beam focus limits
Solution Approach 2:
The patent changes the control approach from geometric parameter control (electrode positions and dimensions) to electrical parameter control (voltage magnitude and duration). This parameter transformation allows for precise control of polarization region wavelengths without being limited by the resolution capabilities of electron beam writing devices, significantly improving ease of manufacture
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 effectively suppresses fluctuations in wavelength conversion efficiency and pulse waveform ripples, enabling stable operation across a wide frequency band without the need for precise control of polarization region dimensions or positions.
Implementation Method 1
An intermediate light is generated in the optical wave guide owing to the Second Harmonic Generation (SGH) of the signal light
Implementation Method 2
A conversion light is also generated owing to the Difference Frequency Generation (DFG) of this intermediate light and pump light
Implementation Method 3
The LiNbO3 substrate is a ferroelectric substance, and so it has dielectric polarization. Therefore on the LiNbO3 substrate, regions of which dielectric polarization are inverted from each other can be formed alternately
Implementation Method 4
The LiNbO3 substrate is a ferroelectric substance
Data Source
AI summary
A wavelength conversion element with a Quasi-Phase Matching structure which can suppress the ripples of fluctuation pulse waveforms of a change efficiency in a frequency band of the waveform conversion, without controlling the positions and dimensions of the polarization regions at high precision. The wavelength conversion element of the present invention has a plurality of first and second polarization regions, formed so that dielectric polarizations are inverted from each other, and an optical wave guide which is formed so as to pass through the first and second polarization regions, in a nonlinear optical substrate. And an absolute value of the wavelength conversion efficiency is set by adjusting the positional coordinates of the first and second polarization regions in a light traveling direction.