Chirped Pulse Generator Using Fiber Length Segmentation
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Solution Overview
Problem
Existing methods for generating chirped optical pulses are hindered by the use of large, heavy, and expensive fiber optic cables, as well as slow rotating mirror/grating assemblies, which fail to meet the needs of applications requiring high-speed capabilities and flexible wavelength and temporal width selection.
Innovation Solution
A device utilizing a pulsed broadband dye laser, a wavelength dispersing element, and fiber-optic cables of varying lengths to create a chirped-like laser pulse, where the energy from the pump laser is focused through lenses and directed to a spectrograph, which separates the pulse into different wavelengths and time-shifts them using optic cables of distinct lengths, allowing for adjustable temporal and spectral widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a long single fiber path is used to create dispersion, then chirped pulse generation is achieved, but the system becomes heavy, expensive, space consuming, and difficult to move
Solution Approach 1:
The patent divides the single long fiber path into multiple shorter fiber segments with different lengths. Each segment introduces a different group delay, collectively achieving the desired dispersion without requiring a single extremely long fiber. This segmentation reduces the total fiber length needed, thereby reducing weight, cost, and space requirements while maintaining the chirped pulse generation capability.
2Reliability
If a rotating mirror/grating assembly is used, then wavelength dispersion is achieved, but the system speed is slow and cannot meet high-speed application requirements
Solution Approach 1:
The patent replaces the mechanical rotating mirror/grating assembly with a static optical system using multiple fiber segments of different lengths. Instead of mechanically rotating components to achieve wavelength dispersion, the system uses the inherent optical path length differences between parallel fiber segments to provide different group delays for different wavelengths. This eliminates moving parts and mechanical rotation, enabling high-speed operation suitable for applications requiring fast response times.
3Device complexity
If fixed wavelength and temporal width are used, then system simplicity is maintained, but flexibility and adaptability for different applications are reduced
Solution Approach 1:
The patent creates a dynamically adjustable system where the temporal width and wavelength characteristics of the chirped pulse can be controlled by selecting different combinations of fiber segments or adjusting the input pulse parameters. The multiple fiber segments with different lengths provide independent control variables, allowing the system to adapt to different application requirements for temporal width and wavelength without requiring complete system redesign, thus achieving both reasonable simplicity and high flexibility.
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 solution enables the generation of chirped laser pulses with longer temporal and spectral widths, suitable for illuminating rapidly varying objects, and allows for selective wavelength and temporal control, overcoming the limitations of prior art by providing a more efficient and adaptable system for generating chirped pulses.
Implementation Method 1
a wavelength dispersing element, and fiber-optic cables of varying lengths to create a chirped-like laser pulse
Implementation Method 2
fiber-optic cables of varying lengths that terminate in a larger core recombining fiber or a simple connector to output a laser pulse that moves or is shifted in time and wavelength over the duration of the pulse
Implementation Method 3
one or more lenses configured to focus the energy from the pump laser
Implementation Method 4
a dye cell configured to receive the energy from the pump laser and, responsive to the energy, output an optic pulse
Data Source
AI summary
A device for creating an optic pulse with different wavelengths separated by time. A pump laser is configured to output energy to a dye cell which, responsive to the energy, outputs an optic pulse. Mirrors direct the optic pulse away from the dye cell towards a spectrograph. The spectrograph has an input and two or more outputs. The spectrograph receives and converts the optic pulse to a wavelength separated optic signal presented on the two or more outputs. A first optic cable has an input end and an output end. The input end receives a first output from the spectrograph. A second optic cable has an input end and an output end. The input end receives a second output from the spectrograph. The second optic cable is a different length than the first optic cable to establish a time shift between the signals exiting the first and second cable.