Semiconductor Laser Chip Layout for 2D Thermal and Carrier Mapping
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Solution Overview
Problem
Existing methods for evaluating and optimizing high-power semiconductor laser chips face challenges in obtaining accurate two-dimensional distributions of temperature and carrier distributions within the active area, leading to inefficient power conversion and reduced beam quality due to inhomogeneous distributions and thermal effects.
Innovation Solution
A method involving setting a window in the N-surface electrode to image spontaneous radiation, using a lens system to capture two-dimensional temperature and carrier distributions, and optimizing the chip structure by adjusting the N-surface electrode segments and gold wire arrangements based on mismatch analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the width of the light-emitting area is increased to improve optical power, then the output optical power increases, but the lateral beam quality deteriorates due to multi-mode emission
Solution Approach 1:
The N-surface electrode is divided into multiple segments along the cavity length direction, with each segment independently controllable. This segmentation allows differential current injection to different regions, enabling precise control of carrier distribution to match the fundamental mode profile while maintaining high total power output.
Solution Approach 2:
Different segments of the N-surface electrode are assigned different current values based on the local light field intensity distribution. Regions with higher light intensity receive higher current to maintain optimal carrier density, while regions with lower intensity receive reduced current to suppress multi-mode emission, achieving local optimization of beam quality.
2Power
If the cavity length is lengthened to improve optical power, then the output optical power increases, but the inhomogeneous distribution of carriers and temperature worsens
Solution Approach 1:
The long cavity is divided into multiple segments along its length, allowing independent control of carrier injection in each region. This enables compensation for thermal gradients and carrier diffusion effects that worsen with length, maintaining uniform effective carrier distribution throughout the extended cavity.
Solution Approach 2:
The current values for different N-surface electrode segments are dynamically adjusted based on the measured or calculated light field intensity distribution and temperature profile. This dynamic control compensates for the inhomogeneous effects that arise in long cavities, maintaining optimal performance throughout the extended structure.
3Loss of information
If existing evaluation methods are used to measure temperature and carrier distribution, then some information can be obtained, but the resolution is insufficient and two-dimensional distribution cannot be achieved
Solution Approach 1:
The system uses the measured spontaneous radiation spectrum and intensity to calculate temperature and carrier distributions, then feeds this information back to optimize the current distribution across N-surface segments. This iterative feedback process enables progressively more accurate measurement and control of two-dimensional distributions with high spatial resolution.
Solution Approach 2:
The patent replaces direct physical measurement probes with optical measurement techniques (spontaneous radiation imaging and spectroscopy) to obtain temperature and carrier distributions. This non-contact optical method achieves high spatial resolution two-dimensional mapping without the mechanical complexity and limited resolution of probe-based methods.
4Manufacturing precision
If the number of N-surface electrode segments is increased to improve carrier distribution control, then the carrier-light field matching improves, but the device complexity increases
Solution Approach 1:
The N-surface electrode is segmented into a moderate number of regions (typically 3-9 segments) along the cavity length, providing sufficient control resolution to match carrier distribution to the light field profile without creating excessive complexity. This optimal segmentation balances control precision with manufacturing feasibility.
Solution Approach 2:
Instead of increasing segmentation indefinitely, the system optimizes the current values (electrical parameters) for each segment to achieve precise carrier distribution control. This parameter optimization approach provides fine control with minimal structural complexity, avoiding the need for excessive physical segmentation.
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
Enables precise evaluation of temperature and carrier distributions without performance impact, facilitating structure optimization that improves efficiency and reduces heat generation by aligning carrier and light field distributions.
Implementation Method 1
spontaneous radiation is generated in an active area of a quantum well of the chip to be tested
Data Source
AI summary
The present application provides a method for performance evaluation and structure optimization of a high-power semiconductor laser chip, and a system for performance evaluation. Wherein the method for performance evaluation of a high-power semiconductor laser chip comprises: setting a window in an N-surface electrode of a chip to be tested; maintaining the chip to be tested in an operating state, wherein spontaneous radiation is generated in an active area of a quantum well of the chip to be tested; imaging the spontaneous radiation at a position outside the chip to be tested; acquiring, by using a spectrometer outside the chip to be tested, a spectrum of the spontaneous radiation to obtain a two-dimensional distribution of temperature of the quantum well of the chip to be tested in the operating state; and acquiring, by using a CCD camera outside the chip to be tested, an image of the spontaneous radiation to obtain a two-dimensional distribution of carriers in the quantum well of the chip to be tested in the operating state. The method for performance evaluation and structure optimization of a high-power semiconductor laser chip provided by the present application can get the temperature distribution and the carrier concentration distribution of the chip to be tested in the operating state with a resolution that is freely adjustable, the operation is convenient and easy to implement, and the accuracy of evaluation results is effectively improved.