Laser Wavelength Tuning via Nonlinear Crystal Temperature Control
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Solution Overview
Problem
Existing laser apparatuses with DFB semiconductor lasers have a narrow tunable wavelength range, making it difficult to achieve adequate wavelength tuning performance.
Innovation Solution
A laser apparatus comprising a fundamental wavelength light generating unit, an optical amplifier unit, a wavelength converting part with nonlinear optical crystals and temperature regulators, and a control unit that adjusts the temperature of the crystals based on stored correspondence information to achieve tunable wavelength output light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a DFB semiconductor laser is used as the laser light generating unit with temperature control to adjust oscillation wavelength, then the oscillation wavelength can be adjusted, but the tuning range of the output wavelength is relatively narrow
Solution Approach 1:
The patent divides the wavelength tuning function into two independent segments: (1) the DFB semiconductor laser temperature control unit that adjusts the oscillation wavelength within its limited range, and (2) the nonlinear optical crystal temperature control unit that performs wavelength conversion to extend the overall tuning range. This segmentation allows each component to operate within its optimal range while achieving broader wavelength coverage through their combination.
Solution Approach 2:
The nonlinear optical crystal acts as an intermediary between the DFB semiconductor laser and the final output. It converts the oscillation wavelength from the laser into a different output wavelength through nonlinear optical processes, effectively extending the tunable wavelength range beyond what the laser alone can provide while maintaining wavelength tuning performance.
2Adaptability or versatility
If the temperature of the DFB semiconductor laser is actively varied to adjust oscillation wavelength, then the output wavelength can be adjusted, but achieving adequate wavelength tuning performance is difficult
Solution Approach 1:
The control unit stores correspondence information in advance that maps between the desired output wavelength and the required temperature settings for both the DFB semiconductor laser and the nonlinear optical crystals. When wavelength tuning is needed, the control unit retrieves the pre-calculated temperature settings from this stored correspondence data, eliminating the need for complex real-time calculations and making wavelength adjustment straightforward and reliable.
Solution Approach 2:
The patent implements a feedback control mechanism where temperature sensors monitor the actual temperatures of the DFB semiconductor laser and nonlinear optical crystals, and the control unit adjusts the temperature settings based on the difference between the target temperatures (from correspondence information) and the actual measured temperatures. This feedback loop ensures accurate and stable wavelength tuning performance.
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 solution expands the tunable wavelength range of the laser apparatus, enabling sufficient wavelength tuning performance and broader applicability in light therapy, device manufacturing, and object inspection applications.
Implementation Method 1
a plurality of nonlinear optical crystals, wherein each of the nonlinear optical crystals performs wavelength conversion of the laser light amplified by the optical amplifier unit
Implementation Method 2
the temperature control apparatuses control the temperatures of the nonlinear optical crystals in order to adjust their phase matching angles during wavelength conversion
Data Source
AI summary
A fundamental wavelength light generating unit generates light of a fundamental wavelength in accordance with an output wavelength instruction signal. An optical amplifier unit amplifies the light of the fundamental wavelength. A wavelength converting part includes nonlinear optical crystals that each perform wavelength conversion and temperature regulators that each regulate the temperature of the corresponding nonlinear optical crystal, wherein the wavelength converting part converts the light amplified by the optical amplifier unit to light of the wavelength indicated by the output wavelength instruction signal. A storage unit stores correspondence information that indicates a correspondence relationship between the wavelength of the output light and the temperature of each of the nonlinear optical crystals based on the corresponding wavelength. A control unit controls each of the temperature regulators such that the temperature of the corresponding nonlinear optical crystal reaches the temperature to be set in accordance with the output wavelength instruction signal.