Spectral-Temporal Multiplexer for Fiber Laser Power Scaling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fiber laser amplifier systems face limitations in combining multiple fiber beams coherently to achieve high output power due to bandwidth and phasing errors, leading to restricted power levels and increased system complexity when multiple amplifier chains are used.
Innovation Solution
A pulsed fiber laser amplifier system employs a single fiber amplifier chain that amplifies pulses at different wavelengths at various times, using a spectral-temporal beam combiner with wavelength-dependent temporal delay optics to combine pulses spectrally and temporally, reducing the number of components and overcoming peak power limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple fiber beams are combined coherently using DOE and phase modulators, then beam quality is maintained, but the number of fiber beams that can be combined is limited due to bandwidth and phasing errors
Solution Approach 1:
The patent combines multiple fiber amplifier chains by summing their output pulses in the time domain using a beam combiner. Multiple seed sources at different wavelengths are amplified by separate fiber chains and then temporally overlapped to create a single high-power output pulse, merging the power output of multiple chains without requiring complex coherent combination control
Solution Approach 2:
The system uses periodic pulse trains from multiple seed sources, where each seed source generates pulses at regular intervals. By controlling the timing and repetition rates, the pulses from different chains are periodically summed in the time domain, enabling high-power output through temporal accumulation rather than spatial coherent combination
2Power
If multiple fiber amplifier chains are used to increase power output, then higher power levels are achieved, but system complexity and cost increase significantly
Solution Approach 1:
The system segments the amplification process across multiple fiber chains, where each chain amplifies a separate wavelength channel. The segmentation occurs in the spectral domain with each chain handling a specific wavelength, and the results are recombined in the time domain, allowing independent optimization of each chain while achieving high total power
Solution Approach 2:
The patent transitions from spatial combination (coherent combination in the same time slot) to temporal combination (summing pulses at different times). By adding the time dimension to the combination process, the system can combine multiple amplifier chains without the bandwidth and phasing constraints that limit spatial combination approaches
3Power
If spectral beam combination is used to combine multiple wavelengths, then power is increased, but the combination of pulses in time and space becomes more complex
Solution Approach 1:
The patent introduces a temporal intermediary approach where pulses from different wavelengths are delayed and summed in the time domain before final combination. The beam combiner acts as an intermediary device that temporally overlaps the pulses, simplifying the combination process by separating spectral and temporal dimensions of the combination operation
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 approach allows for higher power output while maintaining beam quality and reducing system complexity, enabling efficient pulse energy delivery for applications like 3-D Ladar range finding with improved spatial resolution and reduced system costs.
Implementation Method 1
spectral-temporal beam combiner with wavelength-dependent temporal delay optics to combine pulses spectrally and temporally
Implementation Method 2
diffractive optical element (DOE) that combines the coherent fiber beams
Implementation Method 3
a fiber laser amplifier that employs a doped fiber and a pump beam to generate the laser beam
Implementation Method 4
Each fiber beam is provided to a phase modulator that controls the phase of the beam so that the phase of all the fiber beams is maintained coherent
Data Source
AI summary
A pulsed fiber laser amplifier system including a plurality of optical seed beam sources each generating a seed pulse beam at a different point in time and at a different wavelength than the other seed beam sources. The system further includes an optical coupler responsive to each of the seed pulse beams that outputs the pulse beams on a common optical path as a pulsed envelope beam. The system also includes a plurality of fiber amplifier stages responsive to the pulse envelope beam from the optical coupler that amplifies each pulse in the pulse envelope beam. The system further includes a spectral-temporal beam combiner that provides a separate delay for each of the amplified pulses in the pulse envelope beam so as to output a single output beam pulse that is in overlap of all of the individual amplified pulses in the pulse envelope beam.