Grating-Lens Dispersion Compensator for Fiber Laser TOD
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Solution Overview
Problem
Current fiber laser systems face limitations in scalability due to third-order dispersion (TOD), which hinders the development of high-energy systems with compact and reliable CPA systems, as conventional methods struggle to effectively de-chirp pulses to original widths.
Innovation Solution
A dispersion compensator is implemented in the fiber laser system using a combination of grating lenses and prisms, along with a deformable mirror, to generate negative TOD and GVD, allowing for effective compensation of higher-order dispersions, particularly utilizing highly dispersive materials like SF10 prisms and chirped gratings to achieve flexible and efficient pulse compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fiber stretcher and Treacy compressor are used to replace grating-lens combination, then system reliability is improved, but third-order dispersion compensation capability deteriorates
Solution Approach 1:
The patent combines grating-lens combination with fiber stretcher and Treacy compressor into a hybrid dispersion compensation system. The grating-lens pair provides negative TOD to counteract the positive TOD from the fiber stretcher, while the fiber components maintain system reliability. This merging allows simultaneous achievement of reliable operation and effective higher-order dispersion compensation.
2Volume of moving object
If conventional fiber stretcher and Treacy compressor are used, then system compactness is improved, but de-chirping performance deteriorates due to positive TOD
Solution Approach 1:
The patent introduces grating-lens combination to change the dispersion parameters of the system. The grating-lens pair generates negative third-order dispersion to balance the positive TOD from the fiber components. By adjusting the grating groove density, incidence angle, and focal length of lenses, the system achieves effective de-chirping performance while maintaining compactness.
3Power
If fiber laser system uses CPA for short pulse high power amplification, then output energy is improved, but scalability deteriorates due to TOD limitations
Solution Approach 1:
The grating-lens combination acts as an intermediary element that mediates between the fiber stretcher and Treacy compressor. It introduces negative TOD to counterbalance the positive TOD from the fiber components, enabling effective pulse compression and de-chirping. This intermediary allows the system to achieve higher output energy while maintaining scalability by resolving the TOD limitation.
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 enables the production of high-quality, compact, and reliable fiber laser systems capable of compensating TOD, thereby overcoming the limitations of TOD-induced dispersion, allowing for higher energy pulses to be re-compressed to their original widths, enhancing the scalability and performance of CPA systems.
Implementation Method 1
the third order dispersion (TOD) limits the scalability of the laser systems... both fiber stretcher and Treacy compressor have positive TOD... a pair of grating lenses and a pair of prisms as a combined compensator to compensate a higher order dispersion including the TOD
Implementation Method 2
a pair of grating lenses and a pair of prisms as a combined compensator... a pair of prisms with grating surface
Data Source
AI summary
A fiber Chirped Pulse Amplification (CPA) laser system includes a fiber mode-locking oscillator for generating a laser for projecting to a fiber stretcher for stretching a pulse width of the laser. The fiber CPA laser system further includes a multistage amplifier for amplifying the laser and a high-order dispersion compensating compressor for compensating high order dispersions and compressing the pulse width of the laser. The high-order dispersion compensating compressor further includes a pair of gratings coupled with a pair of prisms, a grating pair engraved on the surfaces of a pair of prisms, a chirped grating pair and a phase modulator consists of a grating and a deformable mirror, for generating a negative group velocity dispersion (GVD) and a negative third order dispersion (TOD) for the laser.