Three Terminal Broad Area Laser Electrode Segmentation
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Solution Overview
Problem
Generating very high power, short pulses of laser light using semiconductor lasers is challenging due to inductance and capacitance limitations in the circuitry and the lasers themselves, which restricts pulse energy and duration.
Innovation Solution
Incorporating multiple electrodes to drive the gain medium of the semiconductor laser, where one electrode provides the majority of the energy (pump electrode) and another controls the transparency and gain of a second region to switch the laser on and off (switch electrode), allowing for increased pulse energy and reduced duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the power of a pulse of light emitted by a light pulse emitter is increased, then the energy of the laser pulse is improved, but the width of the emitted pulses increases
Solution Approach 1:
The patent divides the single electrode into two separate electrodes: a pump electrode that delivers high current for a longer duration to provide pulse energy, and a switch electrode that delivers low current for a short duration to control pulse timing. This segmentation allows independent optimization of energy delivery and pulse width control, resolving the contradiction between high pulse energy and short pulse duration.
2Device complexity
If a single electrode is used to provide both energy and timing control, then the device complexity is reduced, but the ability to generate high power short pulses is limited
Solution Approach 1:
The patent segments the electrode function into two separate electrodes with distinct roles: the pump electrode handles energy delivery while the switch electrode handles timing control. This functional segmentation enables the generation of high peak power pulses with precise timing, overcoming the limitations of single-electrode systems without excessive complexity.
Solution Approach 2:
The patent applies different current characteristics to different electrodes: high current amplitude with longer duration for the pump electrode, and low current amplitude with short duration for the switch electrode. This local differentiation of current quality allows each electrode to be optimized for its specific function, achieving high peak power while maintaining simple device architecture.
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 the generation of high-energy, short laser pulses with narrower widths and higher peak power, decoupling the energy provision from the pulse timing and reducing the current required for switching, thus overcoming the limitations of single-electrode systems.
Implementation Method 1
a pump electrode electrically coupled to the first portion of the gain medium, wherein the pump electrode is configured to apply a current through the gain medium that provides energy for lasing
Implementation Method 2
a switch electrode electrically coupled to the second portion of the gain medium, wherein the switch electrode is configured to apply a current through the gain medium that controls a transparency of the second portion of the gain medium
Implementation Method 3
the gain medium has an output edge through which photons generated in the gain medium can be emitted
Data Source
AI summary
Example embodiments relate to light detection and ranging (lidar) devices or other apparatus that incorporate laser light emitters capable of increased pulse energies and decreased pulse durations. These laser light emitters include a gain medium having two portions to which a pump electrode and a switch electrode, respectively, are coupled. The pump electrode is configured to apply a current through the gain medium that provides energy for lasing and the switch electrode is configured to apply a current through the gain medium that controls a transparency of the second portion of the gain medium. Thus the switch electrode, which controls the timing of emitted light pulses, can be driven by a lower current and thus have shorter pulse widths, rise time, and/or fall times, thereby allowing for shorter, higher-energy laser pulses to be emitted.