Wavelength Converter Using Bulk-Type Selective Device
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Solution Overview
Problem
Conventional wavelength converter apparatuses face challenges in maintaining wavelength stability due to temperature control difficulties and mode competition between the laser diode and wavelength selective devices, particularly with fiber Bragg gratings and reflection type volume holographic gratings, leading to light output variations and increased apparatus size.
Innovation Solution
A wavelength converter apparatus employing a bulk-type wavelength selective device, such as a reflection type holographic grating or diffraction grating, optically joined with an optical fiber, where the optical fiber length is set longer than the coherence length to minimize mode competition and allow easy temperature control of the bulk-type device, ensuring stable wavelength locking without strict temperature control of the fiber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fiber Bragg grating is employed as the wavelength selective device, then wavelength selection is achieved, but temperature control becomes difficult and the apparatus size increases
Solution Approach 1:
The patent changes the physical form of the wavelength selective device from a fiber-based grating to a bulk-type element. This parameter change allows the device to be temperature-controlled more effectively while maintaining wavelength selection functionality, thereby resolving the contradiction between wavelength stability and temperature control complexity
Solution Approach 2:
The patent extracts the wavelength selective function from the optical fiber medium and implements it using a separate bulk-type wavelength selective device. This separation allows independent optimization of the fiber coupling and the wavelength selection mechanisms, reducing the overall system complexity while maintaining performance
2Reliability
If a reflection type volume holographic grating is used, then wavelength selection is achieved, but mode competition occurs and apparatus size increases
Solution Approach 1:
The patent changes the configuration of the wavelength selective device from a reflection type volume holographic grating to a bulk-type element with transmission geometry. This parameter change eliminates mode competition between the laser resonator and the wavelength selective device, while also allowing for a more compact optical path design
3Volume of moving object
If optical fiber is used for wavelength selection, then compact design is possible, but temperature uniformity becomes difficult to maintain
Solution Approach 1:
The patent extracts the wavelength selection function from the optical fiber and implements it using a bulk-type wavelength selective device. This separation allows the optical fiber to be used only for light transmission in a compact configuration, while the bulk device handles wavelength selection with effective temperature control
Solution Approach 2:
The patent changes the physical state and form of the wavelength selective element from a fiber-based structure to a bulk-type structure. This parameter change enables better thermal management while maintaining the compact overall apparatus design through optimized optical coupling
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 configuration stabilizes the wavelength locking mechanism, reduces the need for precise temperature control of the optical fiber, and allows for a compact apparatus design with reduced light output variations, while facilitating easier temperature management of the wavelength selective device.
Implementation Method 1
an optical fiber optically joined with an output side of the laser diode
Implementation Method 2
a wavelength selective device of bulk type placed in an output side of the optical fiber
Data Source
AI summary
A compact apparatus is provided for stably converting a wavelength of a laser diode with the use of an optical fiber and a wavelength selective device. Employing a bulk type element as a wavelength selective device makes the action of controlling the temperature of the device easy, and can stabilize the wavelength emitted from the laser diode.The optical fiber (2) is placed between the output side of a laser diode (1) and a wavelength selective device (5) of bulk type.While the optical fiber (2) is arranged compact in the form of a coil, the length of an extra-cavity defined by the wavelength selective device (5) is sufficiently longer than the coherence length. Accordingly, the action of stably converting the wavelength can be carried out by the compact apparatus.