Waveform-Agile Laser Transmitter for Constant Peak Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LADAR transmitters are limited by their inability to maintain constant peak power over a broad range of pulse repetition frequencies (PRFs), leading to inefficiencies and increased risk of optical damage, while also being slow to adjust to changing PRF requirements, which hampers their flexibility and responsiveness.
Innovation Solution
The implementation of a waveform controller that generates a script with adjustable pulse repetition frequency, pulse duration, and pulse amplitude settings to maintain constant peak power at a nonlinear wavelength converter, allowing for rapid PRF changes without active beam adjustments, enabling continuous operation across a wide PRF range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional LADAR transmitters operate over a broad range of rapidly-changing pulse repetition frequencies (PRFs), then the system achieves greater flexibility and adaptability in ranging and imaging applications, but the peak power varies significantly and optical damage risk increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the pulse width and peak power of laser pulses as the PRF changes. The control system modifies these parameters in real-time to maintain constant intensity at the wavelength converter, preventing optical damage while enabling broad PRF operation. This is achieved through a feedback mechanism that monitors PRF and automatically adjusts pulse characteristics.
Solution Approach 2:
The patent implements feedback control where the system continuously monitors the PRF and uses this information to adjust the pulse width and peak power. The control system receives feedback about the operating conditions and automatically modifies the laser pulse parameters to maintain optimal intensity at the nonlinear wavelength converter, thereby preventing optical damage while maintaining PRF flexibility.
2Reliability
If conventional LADAR transmitters use active adaptive optics to adjust beam size and intensity at the fundamental wavelength, then the intensity at the wavelength converter can be maintained, but the adjustment speed is too slow for rapid pulse-to-pulse PRF dithering
Solution Approach 1:
The patent replaces the mechanical active adaptive optics system with an electronic control mechanism that directly modulates the laser pulse width and peak power. Instead of using mechanical components to physically adjust beam size and intensity, the system uses electronic signals to control the laser source, achieving much faster response times that enable pulse-to-pulse PRF dithering while maintaining accurate intensity control at the wavelength converter.
3Adaptability or versatility
If conventional LADAR transmitters use beamline optics adjustment to switch between LADAR modes, then the system can adapt to different operating conditions, but transmitter down time increases during mode switching
Solution Approach 1:
The patent applies preliminary action by pre-configuring the electronic control system with multiple operational profiles or lookup tables that correspond to different LADAR modes. When a mode change is required, the system simply switches to the pre-calculated parameters rather than performing real-time optical adjustments. This eliminates the need for physical beamline optics adjustment and reduces mode switching time to negligible levels.
4Reliability
If the pulse energy is increased to maintain constant peak power over a broad PRF range, then the intensity at the wavelength converter remains constant, but the pulse width must be extended which may affect temporal resolution
Solution Approach 1:
The patent applies dynamics by making the pulse width a dynamic parameter that automatically adjusts with PRF changes. Rather than using fixed pulse widths, the system continuously varies the pulse duration in real-time according to the current operating conditions. This dynamic adjustment allows the system to maintain constant peak power and intensity at the wavelength converter while adapting pulse width to preserve temporal resolution requirements for different ranging and imaging applications.
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 allows for a single laser transmitter to operate in various modes, providing enhanced flexibility and control, maintaining constant peak power and output quality across a broad PRF range, thus addressing the limitations of existing LADAR transmitters.
Implementation Method 1
LADAR transmitters often use nonlinear wavelength converters that are sensitive to peak power changes at the fundamental wavelength
Data Source
AI summary
A laser transmitter including a waveform controller arranged to generate a waveform script having at least one of a pulse repetition frequency setting, a pulse duration setting, and a pulse amplitude pre-warp setting. The transmitter also includes an optical waveform generator arranged to: i) receive the waveform script, ii) generate pre-warped signal pulses based on the waveform script to compensate for gain distortion effects of a laser power amplifier, and iii) output the pre-warped signal pulses. The laser power amplifier is arranged to: i) receive the pre-warped signal pulses, ii) receive a continuous wave signal, and iii) output amplified signal pulses that maintain a substantially constant drive intensity at the input of a non-linear wavelength converter. The non-linear wavelength converter is arranged to receive the amplified signal pulses and emit wavelength-converted pulses.