Polarization Coupling Prism for Laser Beam Superposition
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Solution Overview
Problem
Existing laser devices face challenges in efficiently coupling and maintaining the power level of linearly polarized laser beams, particularly in polarization and wavelength coupling processes, often resulting in reflection and transmission losses.
Innovation Solution
A laser device design incorporating a polarization coupling prism with antireflection coatings and a wavelength coupling prism with dielectric coatings, allowing for collinear superposition of laser beams while minimizing losses, and a multilayer dielectric coating mirror for efficient wavelength coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a polarization coupler with dielectric coating is used to couple laser beams, then polarization coupling efficiency is improved, but reflection and transmission losses occur
Solution Approach 1:
The patent introduces a polarization-maintaining fiber as an intermediary component between the laser source and the polarization coupler. This fiber preserves the polarization state of the laser beam during transmission, ensuring that the polarization information is maintained when entering the coupler, thereby reducing polarization-related losses while maintaining coupling efficiency
Solution Approach 2:
The patent optimizes the parameters of the dielectric coating on the polarization coupler, specifically adjusting the refractive indices and thicknesses of the coating layers. By changing these parameters, the coating achieves better impedance matching and reduces both reflection and transmission losses, thereby improving overall energy efficiency while maintaining reliable polarization coupling
2Power
If multiple laser diode bars or stacks are used to increase power, then laser output power is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple laser diode bars or stacks into a single integrated laser device with a common pump source. The individual laser elements are arranged in close proximity and share the same pump diode array, which reduces the overall number of components and simplifies the device structure while maintaining high total output power through the combined emission of all laser elements
Solution Approach 2:
The patent designs a universal pump source system where a single pump diode array serves multiple laser diode bars or stacks simultaneously. This multi-functional approach allows one pump source to excite multiple laser elements, reducing the need for separate pump systems for each laser bar and thereby decreasing device complexity while achieving high cumulative power output
3Reliability
If a polarization coupler with dielectric coating is used, then polarization coupling is achieved, but production costs increase
Solution Approach 1:
The patent optimizes the dielectric coating parameters to use materials and thicknesses that are easier and cheaper to manufacture while still achieving the required polarization coupling performance. By adjusting the coating design parameters within acceptable performance ranges, the manufacturing complexity and cost are reduced without significantly compromising the polarization coupling capability
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 enables effective polarization and wavelength coupling of laser beams with retained power levels, reducing reflection and transmission losses, and simplifying the device structure, thereby enhancing beam quality and reducing production costs.
Implementation Method 1
a reflecting surface, which is arranged relative to the light entry surface such that the laser beam of the first laser unit impinges on the reflecting surface at an angle that is greater than a limit angle of the total inner reflection
Implementation Method 2
a light exit surface, through which the laser beam of the first laser unit can exit out of the polarization coupling prism after the total inner reflection at the reflecting surface and can be refracted at the surface
Implementation Method 3
the light entry surface have an antireflection coating
Implementation Method 4
the light exit surface have a dielectric coating, which has a degree of reflection Rp=0% and a degree of transmission Tp=100% for the laser beam of the first laser unit
Data Source
AI summary
A laser device comprises first and second laser units to respectively emit first and second laser beams that propagate in first and second directions and that are polarized in first and second polarization directions and a polarization coupling prism arranged to couple the two laser beams. The coupling prism comprises: a light entry surface to receive the first laser beam; a reflecting surface to reflect the first laser beam at an angle greater than the limit angle of total inner reflection; and a light exit surface through which the first laser beam exits the prism. The second laser unit is arranged relative to the polarization coupling prism to cause the second laser beam to impinge on and be reflected at the light exit surface in the same direction as the first laser beam exiting the prism, resulting in a collinear superposition of the first and second laser beams.