Related Experiment Video
Updated: Jan 28, 2026

Automation of Mode Locking in a Nonlinear Polarization Rotation Fiber Laser through Output Polarization Measurements
Published on: February 28, 2016
Polarization-maintaining nonlinear-amplifying-loop-mirror mode-locked fiber laser based on a 3 × 3 coupler
A new all-polarization-maintaining (PM) nonlinear-amplifying-loop-mirror (NALM) fiber laser using a 3×3 coupler achieves stable mode-locking with reduced pump power and exceptionally low noise. This robust laser operates reliably even under mechanical vibrations.
Area of Science:
- Optics and Photonics
- Laser Physics
- Fiber Laser Technology
Background:
- Mode-locked fiber lasers are crucial for various applications requiring ultrashort pulses.
- Polarization-maintaining (PM) configurations are essential for stable laser operation.
- Nonlinear-amplifying-loop-mirror (NALM) mode-locking offers a robust mechanism for generating ultrashort pulses.
Purpose of the Study:
- To demonstrate a novel all-polarization-maintaining (PM) nonlinear-amplifying-loop-mirror (NALM) mode-locked Er-fiber laser.
- To investigate the performance benefits of using a 3×3 coupler in a PM-NALM laser.
- To assess the noise characteristics and vibration robustness of the proposed laser design.
Main Methods:
- Development of an all-PM fiber laser incorporating a 3×3 coupler for NALM mode-locking.
- Characterization of the mode-locking threshold and pump power requirements.
- Measurement of relative intensity noise (RIN) across a wide frequency range.
- Evaluation of laser stability under external mechanical vibrations.
Main Results:
- The 3×3 PM-NALM laser achieved mode-locking with 1.5 times less pump power than a comparable 2×2 design.
- A minimum relative intensity noise (RIN) level of -155 dB/Hz was recorded, with an integrated RIN of 0.0022% (10 Hz-1 MHz).
- The laser demonstrated exceptional robustness, maintaining stable mode-locked operation for over 60 minutes under continuous 1.5 grms vibrations.
Conclusions:
- The 3×3 coupler intrinsically provides the necessary phase bias for easy mode-locking initiation in PM-NALM lasers.
- This laser design offers one of the lowest integrated RIN values reported for free-running mode-locked lasers.
- The demonstrated robustness against vibrations makes this laser suitable for demanding applications.
More Related Videos
08:48Low-cost Custom Fabrication and Mode-locked Operation of an All-normal-dispersion Femtosecond Fiber Laser for Multiphoton Microscopy
Published on: November 22, 2019
07:56A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
Related Concept Videos
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
Piaget's Stage 3 of Cognitive Development
Conservation and Constancy of Quantity
A significant cognitive milestone in the...
Group Polarization
Nonlinear Pharmacokinetics: Causes of Nonlinearity
Nonlinear drug absorption can occur when the process is rate-limited by solubility, carrier-mediated transport systems, or saturation of the presystemic gut wall or hepatic metabolism. For instance, high doses of riboflavin...
BJT Amplifiers
In BJT amplifier configurations, particularly in common-emitter setups, the transistor's role...
Operational Amplifiers