Beam Offset Plate for Laser Diode Stacking
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Solution Overview
Problem
The existing laser diode packages face limitations in increasing the number of combined beams due to the stair-step architecture, which leads to increased thermal paths and reduced power and reliability of laser diodes, as the thermal path increases with step heights, negatively affecting laser diode performance.
Innovation Solution
The use of beam offset plates to vertically offset laser beams, allowing them to be stacked in the fast axis without the need for a stairstep substrate, thereby reducing thermal paths and improving the alignment of beams onto an optical waveguide, such as an optical fiber, using materials like fused silica or high-index glasses to minimize aberrations and absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If laser diodes are arranged in a stair-step pattern to stack beams in the fast axis, then beam stacking is achieved, but thermal paths increase with step heights reducing power and reliability
Solution Approach 1:
Beam offset plates are introduced as intermediary optical elements between the laser diodes and the beam combination path. These plates laterally shift the beams to achieve stacking without requiring physical elevation of the laser diodes themselves, thus maintaining uniform thermal paths while achieving the desired beam configuration
Solution Approach 2:
The mechanical stair-step elevation system is replaced with an optical beam shifting system using offset plates. Instead of mechanically elevating laser diodes to create beam separation, the patent uses optical elements to laterally shift the beams after they leave the diodes, achieving the same stacking effect without the thermal penalties
2Power
If the number of laser diodes is increased to increase total available power, then power output increases, but the number of beams that can be practically combined is limited by the beam stack size
Solution Approach 1:
The patent transitions from vertical stacking (single dimension) to lateral shifting in the horizontal plane (another dimension). By using beam offset plates to shift beams laterally, the system can accommodate more beams in the stack without increasing the vertical height, effectively adding a dimensional degree of freedom to the beam arrangement
3Shape
If stair-step architecture is used to physically separate beams in the fast axis, then beam separation is achieved, but laser diodes operate at increasingly higher temperatures reducing power and reliability
Solution Approach 1:
Beam offset plates serve as intermediary elements that perform the beam separation function without requiring thermal isolation or elevation of the laser diodes. The plates are positioned in the optical path to laterally shift beams, achieving separation while keeping all diodes at the same thermal level
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 solution enables the stacking of more laser beams in the vertical axis without increasing the thermal path, improving the reliability and power of the laser diode package by reducing the negative impact of heat and minimizing optical losses, while allowing for the use of more exotic thermally conductive materials and simplifying the manufacturing process.
Implementation Method 1
A beam offset plate translates an optical path of a laser beam by refraction
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
A laser diode assembly, comprising a plurality of laser diodes each configured to emit respective ones of a plurality of laser beams along parallel and nonoverlapping optical axes and a first beam offset plate (BOP) configured to receive a first of the laser beams on a first input surface, the first laser beam having a first input optical axis, the first BOP configured to transmit a first output laser beam that has a first vertical offset from the first input optical axis.