Semiconductor Laser Assembly Dispersion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor laser devices struggle to generate ultrashort pulse laser light with durations of 100 femtoseconds or less due to limitations in group velocity dispersion control and frequency shift asymmetry caused by self-phase modulation.
Innovation Solution
A semiconductor laser device assembly incorporating a dispersion compensation optical system with a spatial phase modulator, including a reflective liquid crystal display or wavefront compensation device, to control group velocity dispersion and compensate for frequency shift asymmetry, enabling the generation of ultrashort pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a conventional semiconductor laser device is used, then the device structure is simple and easy to manufacture, but the pulse time width cannot be narrowed to 100 femtoseconds or less due to insufficient group velocity dispersion control
Solution Approach 1:
The laser device is divided into separate functional modules: a laser light source unit and a dispersion compensation optical system unit. This segmentation allows the dispersion compensation function to be added without redesigning the entire laser device, thus narrowing the pulse time width to 100 femtoseconds or less while maintaining relatively simple manufacturing processes for each module.
Solution Approach 2:
A spatial phase modulator is introduced as an intermediary component between the laser light source and the output. This modulator acts as a mediator to control the group velocity dispersion of the laser light, enabling pulse width compression to 100 femtoseconds or less without requiring fundamental changes to the semiconductor laser device structure.
2Duration of action of moving object
If dispersion compensation is added to narrow pulse width, then the pulse time width can be reduced to 100 femtoseconds or less, but the device complexity increases due to additional optical components
Solution Approach 1:
The spatial phase modulator serves multiple functions simultaneously: it controls the group velocity dispersion to narrow the pulse width to 100 femtoseconds or less, and it also compensates for frequency shift asymmetry caused by self-phase modulation. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
Solution Approach 2:
The invention changes the control parameters of the spatial phase modulator to dynamically adjust the group velocity dispersion characteristics. By modifying the phase modulation parameters, the system achieves pulse width compression to 100 femtoseconds or less and compensates for frequency shift asymmetry without requiring physical structural changes, thus controlling device complexity.
3Duration of action of moving object
If spectrum filtering is applied to generate femtosecond pulses, then the pulse time width can be reduced, but the energy efficiency decreases as only about 10% of the output energy remains in the pulse component
Solution Approach 1:
Instead of using spectrum filtering that discards about 90% of the energy, the invention utilizes the self-phase modulation effect (which was previously considered a source of frequency shift asymmetry and distortion) as a beneficial tool. By compensating for the frequency shift asymmetry through the spatial phase modulator, the system converts this harmful effect into a mechanism that broadens the spectrum and narrows the pulse width to 100 femtoseconds or less while maintaining high energy efficiency.
Solution Approach 2:
The invention changes the approach from spectral filtering to temporal pulse shaping through group velocity dispersion control. By adjusting the dispersion parameters in the spatial phase modulator, the system achieves pulse width compression to 100 femtoseconds or less while preserving the majority of the input energy, thus dramatically improving energy efficiency compared to traditional filtering methods.
4Power
If solid state laser apparatus with large resonator is used, then the laser light can be generated, but the apparatus size becomes large and mechanical stability is difficult to ensure
Solution Approach 1:
The invention replaces the mechanical resonator structure of solid state lasers with a semiconductor laser device that uses optical field feedback for mode synchronization. This substitution eliminates the need for a large physical resonator, maintaining laser output power while significantly improving mechanical stability by removing vulnerable mechanical components.
Solution Approach 2:
The invention changes the operating parameters of the semiconductor laser device, including the injection current and optical cavity length, to achieve mode synchronization and ultrashort pulse generation. This parameter-based control approach replaces the need for large mechanical resonators, ensuring both high laser output and excellent mechanical stability in a compact form factor.
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
The solution effectively narrows the pulse time width to 100 femtoseconds or less, enhancing energy efficiency and peak power, while improving mechanical stability and reducing maintenance complexity.
Implementation Method 1
control a group velocity dispersion value of the laser light exited from the semiconductor laser device per wavelength
Implementation Method 2
compensate an asymmetricity of a frequency shift caused by a self phase modulation occurring within the semiconductor laser device
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Disclosed is a semiconductor laser device assembly including a semiconductor laser device; and a dispersion compensation optical system, where a laser light exited from the semiconductor laser device is incident and exits to control a group velocity dispersion value of the laser light exited from the semiconductor laser device per wavelength.