External Resonator Laser Thermal Layout for Narrower Line Width
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Solution Overview
Problem
Conventional external resonator-type lasers experience increased line width due to temperature non-uniformity in the wavelength selective filter and lens, which affects the coherent length and detection distance in applications like Lidar.
Innovation Solution
Incorporation of heat transfer members made of high thermal conductivity materials, such as silicon, gallium arsenide, or copper, to regulate temperature uniformity in the wavelength selective filter and lens, using epoxy with silver, copper, or carbon nanotubes for attachment, and arranging these members to minimize heat transfer to these components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional external resonator-type laser structure is used, then the device is simple and easy to manufacture, but temperature non-uniformity occurs in the wavelength selective filter and lens causing increased line width
Solution Approach 1:
Heat transfer members are introduced as intermediary components between the thermoelectric cooler and the wavelength selective filter/lens. These members mediate the thermal interaction by providing a controlled thermal pathway that promotes uniform heat distribution across the optical components, thereby reducing temperature non-uniformity and narrowing the laser line width without fundamentally redesigning the entire laser structure.
Solution Approach 2:
The thermal conductivity parameter of the system is changed by introducing heat transfer members with specific thermal properties. By selecting materials with appropriate thermal conductivity values for the heat transfer members, the patent optimizes heat distribution to achieve uniform temperature across the wavelength selective filter and lens, directly addressing the line width issue through parameter optimization rather than structural complexity increase.
2Temperature
If thermoelectric cooler is used for temperature control, then temperature can be maintained at constant level, but heat transfer from outside causes temperature variation in components
Solution Approach 1:
The patent converts the harmful external heat transfer into a beneficial effect by strategically positioning heat transfer members that guide external heat flow in a controlled manner. Instead of allowing uncontrolled heat ingress that causes temperature variations, the heat transfer members channel the external heat to complement the thermoelectric cooler's operation, promoting uniform temperature distribution across the optical components.
Solution Approach 2:
Heat transfer members serve as intermediary thermal pathways between the external environment and the optical components. These intermediaries filter and distribute external heat in a controlled fashion, preventing direct localized heating of the wavelength selective filter and lens while maintaining overall temperature uniformity when combined with the thermoelectric cooler.
3Reliability
If wavelength selective filter and lens are arranged above thermoelectric cooler, then temperature control is possible, but position-dependent temperature variation occurs
Solution Approach 1:
The patent applies local quality by positioning heat transfer members at specific locations relative to the wavelength selective filter and lens. By placing these thermal management components in strategic positions, the system creates localized thermal pathways that address specific hot or cold spots, ensuring uniform temperature distribution across different positions of the optical components while maintaining overall temperature control.
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 enhances temperature uniformity, thereby reducing line width and increasing the measurement distance in laser interference applications by maintaining consistent wavelength transmission.
Implementation Method 1
two-sided heat transfer members disposed on at least one side of at least one of the lens and the wavelength selective filter and made of a material having a higher heat transfer rate than the lens and the wavelength selective filter
Implementation Method 2
a thermoelectric cooler 500 is a component used to maintain a temperature of components arranged above the thermoelectric cooler 500 at a constant level
Implementation Method 3
using epoxy with silver, copper, or carbon nanotubes for attachment
Data Source
AI summary
An external resonator-type laser having a narrow line width according to the present disclosure includes a gain chip having a laser gain, a lens for collimating light emitted from the gain chip into parallel light, and a wavelength selective filter for transmitting light having a specific wavelength among the light collimated through the lens, wherein two-sided heat transfer members disposed on at least one side of at least one of the lens and the wavelength selective filter and made of a material having a higher heat transfer rate than the lens and the wavelength selective filter, are included.