On-Chip Solid-State Laser Resonator for Lower Threshold Lasing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing monolithic solid-state lasers have relatively large mode sizes, high lasing thresholds, and low integration due to limited refractive index differences in waveguide structures, leading to larger resonator and device sizes.
Innovation Solution
An optically pumped on-chip solid-state laser with a dielectric resonator having a higher refractive index than the solid gain media substrate, utilizing evanescent-field coupling and a magneto-optical effect to reduce mode size and lasing threshold, and enhance integration, with resonator designs such as traveling-wave ring and F—P type standing-wave resonators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If femtosecond laser direct writing, ion implantation, and ion exchange techniques are used to form waveguide structures, then the refractive index change of the crystal is induced, but the refractive index difference between the waveguide and the surrounding media is small, resulting in large mode size
Solution Approach 1:
The patent changes the refractive index parameter by using a dielectric resonator material with significantly higher refractive index than the gain medium substrate, creating a large refractive index contrast that confines the optical mode to a smaller area, thereby reducing mode size while maintaining ease of fabrication through standard micro-nano techniques
Solution Approach 2:
The patent employs composite material structure consisting of a dielectric resonator layer with high refractive index placed on top of the gain medium substrate, creating a layered composite that achieves both small mode size through high index contrast and compatibility with existing fabrication processes
2Ease of manufacture
If the refractive index difference between waveguide and surrounding media is small, then the waveguide structure is easy to fabricate, but the bending radius of the waveguide is very large, leading to larger size of resonator and other devices
Solution Approach 1:
The patent changes the refractive index parameter by introducing a dielectric resonator with high refractive index, which increases the optical confinement and allows for smaller bending radii in the waveguide structures, thereby reducing the overall size of resonators and other optical devices while maintaining ease of fabrication
3Reliability
If the mode size is large, then the waveguide structure is stable, but the lasing threshold is high
Solution Approach 1:
The patent changes the refractive index parameter by using a dielectric resonator with high refractive index, which reduces the mode size while maintaining waveguide stability through proper structural design, thereby achieving lower lasing threshold by increasing the optical energy density in the gain medium
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
Significantly reduces mode size and resonator size, lowering the lasing threshold and improving device integration and stability, while allowing for flexible preparation using advanced micro-nano technologies like UV lithography and focused ion beam etching.
Implementation Method 1
the resonator has a mode field that overlaps with the solid gain media substrate; pump light is input by the pump light input structure into the resonator from outside, and the pump light in the resonator has an optical field distribution that overlaps with the solid gain media substrate
Implementation Method 2
the laser light generated in the resonator is coupled from the resonator to a waveguide through a coupler by evanescent-field coupling
Implementation Method 3
a material with a magneto-optical effect is provided near the resonator, and the magneto-optical effect is generated by an applied magnetic field, so that frequency degeneracy between clockwise and counterclockwise modes of the resonator is lifted
Data Source
AI summary
An optically pumped on-chip solid-state laser includes a solid gain media substrate and a laser generating structure disposed above the solid gain media substrate. The laser generating structure includes a resonator, a pump light input structure, and a laser light output structure; and the resonator is disposed between the pump light input structure and the laser light output structure, and is propped against or is in clearance fit with the solid gain media substrate.