Fourier Domain Mode Locked Laser Timing Control
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Solution Overview
Problem
Existing electromagnetic radiation sources, such as lasers used in optical coherence tomography, face challenges in synchronization due to dispersion effects and optical frequency shifts, limiting their suitability for generating useable optical coherence data.
Innovation Solution
Incorporating a dispersion compensation module to reduce chromatic dispersion and an optical frequency shifter to compensate for Doppler shifts, along with a bi-directionally tunable filter and high-gain amplifier, to improve timing control and coherence length in Fourier domain mode locked lasers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a tunable filter element is used to sweep optical frequencies periodically, then the laser can generate different optical frequencies over time, but timing errors occur between the propagation time of light inside the cavity and the tuning properties of the filter due to dispersion effects
Solution Approach 1:
The patent applies preliminary action by pre-compensating for dispersion effects using dispersion compensation modules (DCMs) before the light enters the tunable filter. The DCMs are configured to introduce opposite dispersion that cancels out the dispersion accumulated during light propagation through the laser cavity and optical fibers, thereby pre-correcting timing errors before they affect synchronization between the filter tuning and light propagation time.
Solution Approach 2:
The patent implements feedback mechanisms by monitoring the timing synchronization between the tunable filter and the laser cavity and adjusting the dispersion compensation accordingly. The system measures timing errors and uses this information to optimize the dispersion compensation module configuration, ensuring continuous synchronization accuracy despite variations in operating conditions.
2Length of stationary object
If the laser cavity is designed for high optical output, then the coherence length increases, but dispersion effects and Doppler shifts from the tunable filter degrade the optical quality and timing control
Solution Approach 1:
The patent introduces dispersion compensation modules as intermediary elements between the laser cavity and the tunable filter. These DCMs act as mediators that correct dispersion-induced timing errors and optical quality degradation without interfering with the high optical output generation. The DCMs process the light signal to remove dispersion effects, allowing the system to maintain both high coherence length and reliable optical signal quality.
Solution Approach 2:
The patent applies parameter changes by adjusting the dispersion compensation module parameters to optimize performance across different operating conditions. The DCMs are configured with specific dispersion values that compensate for the cumulative dispersion in the laser cavity and optical paths, dynamically adapting to maintain optimal timing control and optical quality while preserving high coherence length.
3Productivity
If both forward and backward sweep directions are used for OCT data collection, then productivity increases, but timing errors and dispersion effects create synchronization difficulties that reduce reliability
Solution Approach 1:
The patent applies preliminary action by pre-configuring the dispersion compensation modules to handle both forward and backward sweep directions. The DCMs are designed to compensate for dispersion effects that occur in both directions, ensuring that timing synchronization is maintained regardless of the sweep direction. This pre-compensation enables the system to reliably use both forward and backward sweeps for OCT data collection without suffering from synchronization errors.
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 configuration enables the generation of useable light output in both forward and backward sweep directions, increases coherence length, and enhances the optical quality of both sweep directions, allowing for faster and more robust OCT data collection.
Implementation Method 1
compensating dispersion such as normal dispersion and anomalous dispersion
Implementation Method 2
compensating for the Doppler shift imparted to the light as it propagates through the tunable filter
Data Source
AI summary
In one embodiment, the invention relates to systems, methods and devices for improving the operation of an electromagnetic radiation source or component thereof. In one embodiment, the source is a laser source. A Fourier domain mode locked laser can be used in various embodiments. The sources described herein can be used in an optical coherence tomography (OCT) system such as a frequency domain OCT system. In one embodiment, laser coherence length is increased by compensating for dispersion. A frequency shifter can also be used in one embodiment to compensate for a tunable filter induced Doppler shift.