Tilted Collimated Beam Multi-Emitter Pump for High Coupling Efficiency
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Solution Overview
Problem
Traditional spatial-multiplexed multi-emitter pumps face challenges in achieving high coupling efficiency due to the fixed step height, which limits the flexibility in accommodating varying numbers of emitters while maintaining convenient heat removal and avoiding beam clipping.
Innovation Solution
The implementation of a staircase formation for laser diode emitters with tilted collimated output beams allows for a variable number of emitters to be used within a consistent physical step height, optimizing coupling efficiency by altering the effective step height through beam tilting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the step height is fixed to provide convenient heat removal, then heat dissipation is improved, but the flexibility in accommodating varying numbers of emitters is limited
Solution Approach 1:
The patent introduces tilt angles for collimated beams that can be adjusted dynamically. By changing the tilt angle of collimated beams from different emitters, the system can accommodate varying numbers of emitters (e.g., 3, 5, or 7 emitters) while maintaining the same fixed step height for heat dissipation. This dynamic adjustment of beam tilt angles provides the needed flexibility without compromising thermal management.
2Reliability
If the step height is increased to reduce beam clipping, then beam quality is improved, but coupling efficiency decreases
Solution Approach 1:
The patent changes the parameter of beam tilt angle to optimize the system. By adjusting the tilt angle of collimated beams, the effective step height is modified, allowing the system to achieve high coupling efficiency (e.g., greater than 65% or greater than 70%) while maintaining appropriate beam quality. This parameter change enables optimization of both coupling efficiency and beam quality without requiring changes to the physical step height.
3Ease of manufacture
If traditional collimated beams are used with fixed step height, then manufacturing is simplified, but coupling efficiency is limited
Solution Approach 1:
The patent applies different tilt angles to collimated beams from different emitters within the same stack. Each emitter's collimated beam can be tilted at a specific angle optimized for its position and characteristics. This local optimization of beam tilt angles improves overall coupling efficiency while maintaining the simplified fixed step height structure for manufacturing convenience.
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 approach enhances coupling efficiency and reduces feedback from optical components, thereby increasing the reliability of the laser diodes and enabling high-brightness spatial-multiplexed output with improved adaptability to different emitter configurations.
Implementation Method 1
each step supporting a corresponding laser diode emitter and a corresponding collimating lens; wherein the stepped support structure transmits light emitted from each of the first, second, and third laser diode emitters to the coupling lens as tilted collimated beams
Implementation Method 2
tilted collimated beams of light that are incident on the coupling lens with a non-zero angle of incidence
Data Source
AI summary
Multi-mode diode emitters are stacked in a staircase formation to provide a spatially-multiplexed output. Improved coupling efficiency is achieved by providing tilted collimated output beams that determine an effective step height of the stepped structure. Since the effective step height is dependent on the tilt angle, a variable number of emitters can be used inside packages having a same physical step height, while still attaining high coupling efficiency.