Laser Beam Phase Modulation for Fast, Damage-Free Switching
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Solution Overview
Problem
Current methods for manipulating high power laser beams are slow and can cause damage to components due to spontaneous emissions, and existing frequency conversion systems are limited by thermally induced phase mismatch and damage thresholds, leading to inefficiencies and potential damage.
Innovation Solution
The use of phase modulators and active phase mismatch compensators to control beam interference and frequency conversion, allowing for rapid activation and deactivation of laser beams, and the implementation of sequential nonlinear crystals with phase mismatch compensators to optimize frequency doubling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If power manipulation methods are used to activate/deactivate laser beams, then the laser beam can be controlled, but the manipulation speed is slow (1-5 KHz) and components may be damaged due to spontaneous emissions
Solution Approach 1:
The system segments the laser beam into multiple individual beams, allowing independent control of each beam. This enables faster manipulation by controlling specific beams rather than manipulating the entire beam's power, thus improving speed while maintaining component safety through targeted control.
Solution Approach 2:
The patent introduces an intermediary control mechanism that manages multiple laser beams through a coordinated system. This intermediary structure allows for rapid activation/deactivation of individual beams without the need for slow power manipulation of the entire laser system, resolving the contradiction between speed and component safety.
2Ease of manufacture
If tapered fiber bundles are used to couple pump and signal light, then coupling is achieved, but numerical aperture increases and mode field diameter changes leading to alignment issues and potential damage
Solution Approach 1:
The system employs dynamic adjustment capabilities for fiber coupling, allowing real-time optimization of alignment parameters. This dynamic approach compensates for the numerical aperture increase and mode field diameter changes caused by tapering, maintaining alignment precision while preserving the manufacturing ease of tapered bundles.
Solution Approach 2:
The patent utilizes parameter changes in the fiber coupling system, specifically adjusting numerical aperture and mode field diameter parameters to optimize both the ease of manufacture and alignment precision. By dynamically modifying these parameters, the system resolves the contradiction between manufacturing simplicity and alignment accuracy.
3Ease of manufacture
If signal fiber is tapered down with pump fibers, then coupling is improved, but core diameter becomes small creating mismatch problems with large mode area double clad fibers
Solution Approach 1:
The system applies local quality differentiation by using different fiber tapering strategies for pump fibers versus signal fibers. This allows the signal fiber to maintain appropriate core diameter for efficient coupling with large mode area double clad fibers, while pump fibers can be optimized for their specific requirements, thus resolving the contradiction between integration ease and coupling efficiency.
Solution Approach 2:
The patent introduces dimensional considerations in fiber coupling by addressing both the transverse dimension (core diameter) and longitudinal dimension (taper length) independently. This multi-dimensional approach allows optimization of signal fiber core diameter for coupling efficiency while maintaining the integrability of the fiber bundle structure.
4Power
If conventional frequency conversion systems are used, then frequency doubling is achieved, but thermally induced phase mismatch and damage thresholds limit efficiency
Solution Approach 1:
The system performs preliminary phase matching adjustments before frequency conversion occurs, compensating for thermal effects in advance. This preliminary action prevents thermally induced phase mismatch from degrading conversion efficiency, allowing high power operation without the limitations of conventional systems.
Solution Approach 2:
The patent implements feedback control mechanisms that monitor and compensate for thermal effects during frequency conversion. This feedback system maintains optimal phase matching conditions even under high power operation, resolving the contradiction between conversion efficiency and thermal limitations.
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 high-speed manipulation of laser beams without component damage and enhances frequency conversion efficiency by minimizing phase mismatch and thermal effects.
Implementation Method 1
plurality of phase modulators configured in (direct or indirect) optical connections with: the seed beam
Implementation Method 2
all arranged to enable constructive or destructive beam interference, at a CBC point
Implementation Method 3
at least two sequential nonlinear crystals (NLCs); a first NLC configured to receive a fundamental beam, at a fundamental frequency (F F ), and to emit a weak second harmonic beam, at a second harmonic frequency (F H )
Implementation Method 4
at least one phase mismatch compensator (PMC), configured to correct a phase relationship between a residual beam, at the fundamental frequency (F F ), and a second harmonic beam, at the second harmonic frequency (F H ), prior to being received by the following NLC
Data Source
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AI summary
Methods and apparatuses for manipulating and modulating of laser beams. The methods and apparatuses enable activating and deactivating of laser beams, while the laser systems maintain their operating power. Further, a hybrid pump module configured to be coupled to an optical fiber having a core and at least one clad, comprising: at least one focusing lens in optical with the optical fiber; plurality of diode modules, each configured to output a multi-mode beam in optical path with the clad; and at least one core associated module, in optical path with the core, configured to provide selected functions. Further, apparatus and methods configured for frequency doubling of optical radiation.