Injection-Locked Laser Seeding for High Phase Coherence
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing injection-locked laser systems face challenges in achieving high phase-coherence, especially at high frequencies, due to limitations in active phase-control and the introduction of phase noise during optical field transmission.
Innovation Solution
A continuous-wave master laser generates seed optical fields with positive and negative frequency shifts, which are used to injection-lock multiple optical amplifiers, ensuring high phase-coherence among the output fields and reducing phase noise through phase lock control loops and frequency locking mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active phase-control is used to phase match two optical fields, then phase-coherence can be maintained within the control frequency range, but phase-coherence deteriorates at high frequencies beyond the control range and servo-bump amplification occurs
Solution Approach 1:
The patent introduces an intermediary optical field (local oscillator or reference beam) that mediates the phase relationship between multiple optical fields. By interfering each optical field with this common intermediary, phase-coherence is established across all fields without requiring direct active phase-control between them, thereby extending coherence to high frequencies beyond the control range.
2Manufacturing precision
If injection-locking is used to achieve single-frequency operation in high-power lasers, then single-frequency performance is improved, but phase noise is introduced during optical field transmission
Solution Approach 1:
The patent employs feedback mechanisms where the optical fields are interfered with a reference beam and the resulting intensity variations are detected and fed back to control systems. This feedback allows real-time correction of phase noise introduced during transmission while maintaining single-frequency operation through injection-locking.
Solution Approach 2:
The patent replaces direct mechanical phase-control mechanisms with optical interference and detection methods. By using optical beating and photodetector signals to monitor and control phase relationships, the system reduces mechanical vibrations and instabilities that would otherwise introduce phase noise.
3Adaptability or versatility
If multiple slave lasers are injection-locked using different modes of a mode-locked master laser, then multiple frequencies can be locked, but residual phase noise remains due to imperfect phase matching
Solution Approach 1:
The patent uses a universal reference beam (local oscillator) that serves as a common intermediary for all optical fields, regardless of their frequency or mode. This universal reference enables consistent phase-coherence measurement and control across multiple frequencies, improving phase matching accuracy compared to pairwise locking methods.
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 achieves reduced phase noise and high phase-coherence across multiple output fields, effectively addressing the limitations of existing injection-locked laser systems by using a single frequency source for noise consistency and phase locking techniques.
Implementation Method 1
optically modulating the continuous-wave output field to produce a first seed optical field having a first frequency (f1) and a second seed optical field having a second frequency (f2)
Implementation Method 2
one or more optical modulators employed to produce from the continuous-wave output field a first seed optical field having a first frequency (f1) and a second seed optical field having a second frequency (f2)
Data Source
AI summary
A method and system for injection-locking multiple optical amplifiers is disclosed. A master laser is employed to generate a continuous-wave output field. Optical modulators then produce first and second seed optical fields from the continuous-wave output field. The first and second seed optical fields provide an input to injection lock one or more optical amplifiers, optionally at different operating frequencies. Since the first and second seed optical fields are generated from the continuous-wave output field then the output fields of the optical amplifiers exhibit a high phase-coherence with each other and with the continuous-wave output field. Employing the first and second optical fields reduces the requirement to induce large frequency shifts on a single optical field. Techniques for phase-locking the output of the injection-locked laser systems are also provided to further reduce phase noise within the systems.