Multispectral Laser Filter Locking for Stable Spectral Intervals
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Solution Overview
Problem
Existing laser sources for multispectral light radiation suffer from poorly controlled spectral ranges and variability due to manufacturing inaccuracies and temperature sensitivity, leading to drifts in spectral intervals and misalignment of emission frequencies.
Innovation Solution
A photonic system comprising a laser bank, a modulator, tunable optical filters, a photodetector, and a locking device that adjusts the resonant frequencies of the filters to match the emission frequencies of the lasers, using modulation signals and feedback mechanisms to achieve precise spectral line separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a bank of distributed feedback lasers is used to generate multispectral light radiation, then the spectral coverage is improved, but the spectral interval control deteriorates due to manufacturing inaccuracies and temperature sensitivity
Solution Approach 1:
The patent implements a feedback mechanism where a photodetector monitors the actual spectral lines produced by the laser bank, and a control device adjusts the laser currents to correct deviations from the target spectral intervals. This closed-loop feedback system compensates for manufacturing inaccuracies and temperature drift, maintaining precise spectral interval control while using a multi-laser bank for broad spectral coverage.
Solution Approach 2:
The patent dynamically changes the operating parameters (currents) of individual lasers in the bank to compensate for spectral drift. By adjusting the injection current of each laser, the system can fine-tune the emission wavelengths to maintain the desired spectral intervals, thereby resolving the contradiction between broad spectral coverage and precise interval control.
2Measurement precision
If the resonant frequencies of filters are modulated to produce feedback signals for locking, then the frequency locking capability is improved, but the device complexity increases due to calibration requirements and error terms
Solution Approach 1:
The patent employs a self-aligning mechanism where the system automatically locks the filter resonant frequencies to the laser spectral lines through feedback control, without requiring manual calibration. The photodetector monitors the transmission spectrum, and the control device automatically adjusts the filter frequencies to match the laser lines, eliminating the need for complex calibration procedures and reducing operational complexity.
3Power
If multiple modulators are locked to a single transmission frequency, then the feedback signal strength is improved, but the spectral line separation deteriorates due to error terms in the feedback signals
Solution Approach 1:
The patent segments the feedback control by assigning dedicated feedback paths and photodetectors to specific spectral lines and corresponding filters. Instead of locking multiple modulators to a single frequency, each filter is independently locked to its corresponding laser spectral line through separate feedback loops. This segmentation prevents error term accumulation and maintains accurate spectral line separation while still achieving strong feedback signals for each individual line.
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 system provides multispectral light radiation with controlled spectral intervals, maintaining alignment even under temperature variations, and enables precise locking of tunable filters in photonic components.
Implementation Method 1
a modulator associated with the bank of lasers, the modulator being configured to generate a modulation signal and to modulate the emission frequency of at least one laser in the bank
Implementation Method 2
a photonic component arranged downstream of the laser bank and comprising a plurality of tunable optical filters each having a plurality of resonant frequencies
Implementation Method 3
A photodetector arranged downstream of the photonic component to establish a signal representative of multispectral radiation produced by the photonic component
Implementation Method 4
a locking device configured to process the signal representative of the multispectral radiation and to adjust the resonant frequencies of the tunable optical filters of the photonic component to the emission frequencies of the bank's lasers
Data Source
AI summary
The invention relates to a photonic system comprising a laser source capable of emitting at least one multispectral light radiation. The photonic system comprises a photonic component having a plurality of tunable optical filters respectively having a plurality of resonant frequencies. The photonic system also comprises a photodetector arranged downstream of the component to establish a signal representative of the multispectral radiation, a modulator associated with the bank of tunable lasers. The laser source also comprises a locking device configured to process the signal representative of the multispectral radiation and to adjust the resonant frequency of a tunable optical filter of the photonic component to the emission frequency of the light radiation of a laser of the bank.