Optical Fiber Input-End Geometry for Cladding Mode Suppression
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Solution Overview
Problem
Existing semiconductor laser modules suffer from damage to adhesive members due to high-power laser light beams propagating in the cladding mode, leading to increased power density and potential damage.
Innovation Solution
The optical part and semiconductor laser module design includes an optical fiber with a cladding portion having a reduced input end face diameter and a light absorber to absorb leaked laser light, reducing the power of laser light beams in the cladding mode and minimizing damage to adhesive members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-power laser light beams are used, then the performance and power output of the semiconductor laser module is improved, but the adhesive members are damaged due to high power density in cladding mode propagation
Solution Approach 1:
The cladding portion is designed with different diameters at different locations: a first cladding diameter at the input end and a second cladding diameter at the output end, where the second is smaller than the first. This local variation in geometry creates different optical properties at different positions, allowing the cladding mode power to be gradually reduced along the propagation direction while maintaining high overall power transmission.
Solution Approach 2:
The patent changes the physical parameter of the cladding portion diameter along the propagation direction. By making the cladding diameter decrease from input to output, the optical confinement and mode distribution are modified, which reduces the power density in the cladding mode at the output end where the adhesive member is located, thereby preventing damage while maintaining high input power.
2Object-affected harmful factors
If the cladding portion diameter is reduced at the output end, then the power density of cladding mode is reduced and adhesive member damage is prevented, but the manufacturing precision requirement increases
Solution Approach 1:
The cladding portion is segmented into different zones along the propagation direction, with each zone having a specific diameter. The first cladding diameter zone at the input end and the second cladding diameter zone at the output end are distinct segments that can be manufactured and controlled separately, making the precision requirement more manageable compared to a continuous gradual transition.
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 design effectively reduces damage to adhesive members by minimizing the power of laser light beams in the cladding mode, allowing for higher power laser light beams to be used without damaging the adhesive members, thus enhancing the performance and durability of the semiconductor laser module.
Implementation Method 1
a light absorber provided around the glass capillary to fix the glass capillary... Such a laser light beam gradually leaks from the cladding portion during propagation, reaches the light absorber by being transmitted through the two adhesive members and the glass capillary, and is absorbed by the light absorber
Data Source
AI summary
An optical part includes: an optical fiber having a core portion and a cladding portion that is formed around the core portion; a light absorber placed around the optical fiber; and an adhesive member that adheres the light absorber and the optical fiber to each other. Further, the cladding portion includes: a main portion extending along a longitudinal direction and having a main portion cladding diameter; and an input end portion positioned closer to a light input side with respect to the main portion, and an input end face cladding diameter at an input end face of the input end portion is less than the main portion cladding diameter.