Mode-locked laser with segmented amplifiers and phase tuners
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Solution Overview
Problem
Prior-art semiconductor mode-locked lasers have a relatively narrow spectral bandwidth, limiting their ability to produce a wide range of wavelengths, which restricts their application in optical communication systems.
Innovation Solution
A mode-locked laser with an optical cavity containing multiple optical amplifiers, intra-cavity dispersion management using separate phase tuners or waveguides, and a loss-modulating element, enabling a wide combined gain spectrum and octave-spanning frequency emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional semiconductor mode-locked laser is used, then the device structure remains simple and cost-effective, but the spectral bandwidth is limited to approximately 20 nm
Solution Approach 1:
The optical cavity is segmented into multiple functional sections, each containing an optical amplifier and phase tuner dedicated to a specific spectral portion. This segmentation allows independent optimization of each spectral band, enabling the system to achieve wide bandwidth (octave-spanning) while maintaining manageable complexity through modular architecture
Solution Approach 2:
The optical cavity is designed to serve multiple functions simultaneously: it provides optical amplification across different spectral bands, dispersion compensation for each band, and mode-locking control. By integrating these multiple functions into a unified cavity structure with serially connected amplifiers and phase tuners, the system achieves wide spectral bandwidth without proportionally increasing overall device complexity
2Adaptability or versatility
If multiple optical amplifiers are added to expand the gain spectrum, then the spectral bandwidth increases, but the intra-cavity dispersion effects become more complex and difficult to manage
Solution Approach 1:
Dispersion management is segmented by assigning a dedicated phase tuner to each optical amplifier and spectral portion. This one-to-one correspondence allows independent dispersion compensation for each spectral band, making the overall dispersion management tractable despite the presence of multiple amplifiers spanning a wide gain spectrum
Solution Approach 2:
Each spectral portion receives localized dispersion compensation through its dedicated phase tuner, which is optimized for that specific spectral band's characteristics. This local optimization approach allows the system to handle complex overall dispersion by managing each spectral region's dispersion properties independently with appropriate local quality control
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 solution allows for a mode-locking regime that produces an optical pulse train with a wide frequency spectrum, enhancing the laser's bandwidth and flexibility in optical communication systems.
Implementation Method 1
multiple optical amplifiers, each dedicated to a respective spectral portion of an optical signal generated by the laser
Implementation Method 2
means for managing intra-cavity dispersion effects, utilizing a separate intra-cavity phase tuner for each such spectral portion
Implementation Method 3
a loss-modulating element coupled to the AWG and adapted to modulate optical losses in the cavity such that an optical pulse train is emitted
Implementation Method 4
the optical cavity of a mode-locked laser of the invention has a perfectly spectrally sampled arrayed waveguide grating (AWG) having a plurality of overlapping optical passbands
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A mode-locked laser (200) that has an optical cavity containing multiple optical amplifiers (210) , each dedicated to a respective spectral portion of an optical signal generated by the laser, wherein the dispersion effects are managed by utilizing a separate intra-cavity phase tuner (212) for each such spectral portion and/or by having appropriately configured waveguides corresponding to different spectral portions . Advantageously, a relatively wide combined gain spectrum provided by the optical amplifiers (210) and the intra-cavity dispersion compensation provided by the phase tuners (212) and/or waveguides enable this laser to realize a mode-locking regime that results in the emission of an optical pulse train having a relatively wide frequency spectrum. In one embodiment, the optical cavity of the mode-locked laser (200) has a perfectly spectrally sampled arrayed waveguide grating (AWG) that is configured to divide the optical signal into the spectral portions and apply these portions to the respective waveguides, optical amplifiers, and phase tuners.