Laser Light Source Optics for Slow-Axis Beam Matching
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Solution Overview
Problem
Existing multiplexing optical systems face challenges in achieving sufficient laser beam incidence on a light guide in the slow axis direction due to larger divergence angles and increased space between semiconductor laser light emitters, leading to reduced output.
Innovation Solution
A light source apparatus is designed with a collimator, a focusing lens, and a magnification optical system between them, which enlarges the beam diameter in the slow axis direction to match that in the fast axis direction, allowing for closer packing of laser diode devices and reduced incident angles on the light guide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If mirrors are used to narrow the space between laser beams on the slow axis side, then the space between semiconductor laser light emitters is reduced, but the beam diameter in the slow axis direction becomes smaller than that in the fast axis direction, resulting in insufficient incidence on the optical fiber
Solution Approach 1:
A beam diameter adjusting optical system is introduced as an intermediary component between the collimator and the optical fiber. This system includes a first lens and a second lens that work together to adjust the beam diameter in the slow axis direction, serving as a mediator to balance the beam dimensions without requiring mirrors that would complicate the spatial arrangement
Solution Approach 2:
The beam diameter in the slow axis direction is adjusted by changing the optical parameters of the beam diameter adjusting system. By modifying the focal lengths and positions of the first and second lenses, the beam diameter is transformed to match the fast axis direction, resolving the asymmetry problem while maintaining compact emitter spacing
2Stability of the object's composition
If the beam diameter in the slow axis direction is smaller than that in the fast axis direction, then the divergence angle in the slow axis direction becomes larger, but the incidence on the optical fiber becomes insufficient
Solution Approach 1:
The beam diameter adjusting optical system acts as an intermediary between the collimator and the optical fiber, transforming the asymmetric beam into a symmetric one. The first lens and second lens work together to reduce the divergence angle in the slow axis direction while maintaining the beam's directional stability, ensuring efficient coupling into the optical fiber
Solution Approach 2:
By changing the optical parameters of the beam diameter adjusting system, specifically the focal lengths and relative positions of the first and second lenses, the beam diameter and divergence angle are transformed. This parameter adjustment reduces the divergence angle in the slow axis direction to match the fast axis direction, thereby improving optical fiber incidence efficiency
3Ease of operation
If collimator lenses are used to shape laser beams into parallel light, then the beam direction is controlled, but the beam diameter in the slow axis direction remains smaller than in the fast axis direction
Solution Approach 1:
The beam diameter adjusting optical system serves as an intermediary component between the collimator and the optical fiber. It receives the parallel beam from the collimator and further processes it to correct the diameter asymmetry, maintaining the parallelism achieved by the collimator while adding the necessary shape correction
Solution Approach 2:
The beam diameter adjusting system changes the optical parameters of the beam by using a first lens and a second lens with specific focal lengths and positions. This transforms the beam diameter in the slow axis direction to match the fast axis direction, achieving symmetric beam shape while preserving the parallelism established by the collimator
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 enables efficient incidence of laser beams on the light guide in both the fast and slow axis directions, reducing the space between laser diode devices and maintaining sufficient output, even with increased numbers of devices.
Implementation Method 1
a collimator disposed on an optical path of a laser beam emitted from each of the laser diode devices
Implementation Method 2
a focusing lens disposed on a downstream side in a direction of an optical axis of each laser diode device relative to the collimator and configured to condense the laser beams
Implementation Method 3
a magnification optical system disposed between the collimator and the focusing lens to bring a beam diameter in a slow axis direction of the laser beam passed through the collimator close to a beam diameter in a fast axis direction
Data Source
AI summary
A light source apparatus 1 includes: a light emitter 2 having a plurality of laser diode devices 22 and packages 24 to hold the respective laser diode devices; a collimator 3 disposed on an optical path of a laser beam emitted from each of the laser diode devices; a focusing lens 5 disposed on a downstream side in a direction of an optical axis of each laser diode device relative to the collimator 3 and configured to condense the laser beams; a light guide 6 disposed on the downstream side in the direction of the optical axis relative to the focusing lens 5; and a magnification optical system 4 disposed between the collimator 3 and the focusing lens 5 to bring a beam diameter Wα2-1 in a slow axis direction of the laser beam transmitted through the collimator 3 close to a beam diameter Wα1-2 in a fast axis direction.