Laser Diode Light Source With Planar TEC Modules
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing packaging solutions for semiconductor laser diodes face challenges in efficient heat removal and achieving symmetric optical beam divergence for effective fiber coupling, leading to complex and costly designs with alignment issues.
Innovation Solution
A light source configuration using planar emitters with fast-axis and slow-axis collimating means, along with redirecting optics, to collimate and align beams into a single, symmetric output suitable for fiber coupling, optimizing heat sinking and beam symmetry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a common heat sink is used to remove heat from multiple laser diodes, then heat removal efficiency is improved, but the device becomes bulky and coupling optics become complex and inefficient
Solution Approach 1:
The patent divides the heat removal and optical coupling function into separate modules. Each laser diode is mounted on its own thermoelectric cooler (TEC) module that serves as both heat sink and optical platform. This segmentation allows independent optimization of thermal management and optical coupling for each diode, avoiding the need for complex bulk optics while maintaining efficient heat removal through parallel TEC operation.
Solution Approach 2:
The TEC module serves multiple functions simultaneously: it acts as a heat sink to remove heat from the laser diode, provides a stable mounting platform for optical components, enables active temperature control through Peltier effect, and serves as a reference plane for optical alignment. This multi-functionality eliminates the need for separate bulky components while maintaining efficient thermal management.
2Device complexity
If laser diodes are stacked together for heat sinking, then the optical arrangement becomes simpler and more compact, but heat removal efficiency decreases because heat flows in serial fashion
Solution Approach 1:
Instead of stacking diodes vertically where heat must flow through multiple layers serially, the patent segments the thermal management system so that each diode has its own TEC module. This allows heat from each diode to be removed independently in parallel through its dedicated TEC, dramatically improving overall heat removal efficiency while keeping the optical arrangement simple and compact.
Solution Approach 2:
The patent transitions from vertical stacking (one-dimensional arrangement) to a planar configuration where multiple TEC modules are arranged side-by-side. This dimensional change allows heat removal paths to be parallel rather than serial, improving thermal efficiency while maintaining compact footprint through efficient use of the planar space.
3Reliability
If individual laser diodes are used instead of a single-bar assembly, then reliability is improved since one failure does not disable neighboring emitters, but heat removal from individual emitters with sub-millimeter pitch becomes difficult
Solution Approach 1:
The patent segments the thermal management system so that each laser diode is mounted on its own TEC module rather than sharing a common heat sink. This segmentation provides two benefits: it maintains the reliability advantage of individual diode operation (failure of one does not affect others) while solving the heat removal challenge by providing dedicated thermal paths for each diode through its own TEC module.
Solution Approach 2:
The patent uses identical TEC module designs for each laser diode position. This copying approach simplifies manufacturing and assembly while ensuring that each diode receives optimal individual heat removal. The standardized TEC module design can be replicated multiple times to accommodate any number of diodes in the array, making the system scalable and manufacturable.
4Shape
If complex multi-faceted reflectors or stair-like heat sink structures are used to combine beams, then beam symmetry is achieved, but the device becomes expensive and difficult to align
Solution Approach 1:
The patent segments the optical coupling function so that each laser diode is independently coupled to its own optical fiber through simple lenses. This eliminates the need for complex multi-faceted reflectors or stair-like structures that would be required to combine multiple beams into a single symmetric output. Each diode-fiber pair is independently optimized, achieving effective coupling without complex alignment-sensitive components.
Solution Approach 2:
Instead of combining multiple laser beams into a single output path using complex optics, the patent inverts the approach by providing independent optical paths from each laser diode directly to its own optical fiber. This inversion eliminates the need for beam combination optics while achieving the same functional result of efficient light coupling, and greatly simplifies alignment requirements.
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 heat removal and compact, cost-effective fiber coupling of high-power laser diodes, improving reliability and reducing alignment complexities, while maintaining high optical efficiency and beam symmetry.
Implementation Method 1
a plurality of fast-axis collimating means, one per each emitter, for collimating the emission of each emitter into a fast-axis collimated beam
Implementation Method 2
a slow axis collimating means, disposed downstream of the fast-axis collimating means, for collimating the fast-axis collimated beams into a single collimated beam
Implementation Method 3
a plurality of redirecting means, for redirecting the fast-axis collimated beams, so as to couple said fast-axis collimated beams to the slow axis collimating means
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
An apparatus for coupling radiation of individual laser diode emitters into a common optical fiber is disclosed. The radiation is collimated along fast axis and combined by using crossed pairs of flat mirrors. The combined beams are collimated by a common slow axis collimating lens. The laser diode emitters are disposed on both sides of an optical axis of the slow axis collimating lens such that the optical path lengths from the emitters to the slow axis collimating lens are equal.