Laser Reservoir Computing With Ring Resonator Feedback
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Solution Overview
Problem
The challenge lies in creating a compact reservoir computing system that can effectively learn and predict time-series data using a laser apparatus as the reservoir, while maintaining a small size and avoiding the complexity of extracting output signals from multiple nodes, which is difficult due to the need for external feedback light with increased propagation distance.
Innovation Solution
The system incorporates a laser apparatus with a feedback waveguide, optical splitter, and ring resonators to achieve a longer delay time for external feedback light, allowing for complex nonlinear input/output characteristics without increasing the system's size, using a configuration that includes a semiconductor laser and optical fiber to adjust the delay time and maintain a compact form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the external propagation distance of the external feedback light is lengthened to achieve complex nonlinear input/output characteristics, then the learning capability is improved, but the size of the laser apparatus is increased
Solution Approach 1:
The patent embeds a ring resonator structure within the feedback path of the laser apparatus. The ring resonator circulates light multiple times through a compact loop, effectively nesting the feedback path within itself. This allows the light to traverse a longer effective propagation distance (achieving complex nonlinear characteristics) while the physical footprint remains compact, resolving the contradiction between learning capability and apparatus size.
Solution Approach 2:
The patent transitions from a linear feedback path to a resonant cyclic path by introducing the ring resonator. This dimensional change in the light propagation topology allows the system to achieve extended effective path length through multiple circulations rather than extending the linear distance, thereby maintaining compact size while enhancing learning capability.
2Adaptability or versatility
If the external propagation distance of the external feedback light is lengthened to achieve complex nonlinear input/output characteristics, then the learning capability is improved, but the device complexity is increased
Solution Approach 1:
By nesting the ring resonator within the existing laser feedback structure, the patent achieves extended propagation distance without adding proportionally complex external components. The resonator integrates into the feedback loop, providing enhanced learning capability while maintaining relatively simple system architecture.
Solution Approach 2:
The ring resonator creates multiple copies of the light signal through cyclic circulation, allowing the same light path to be traversed repeatedly. This copying mechanism achieves extended effective propagation distance without requiring proportionally longer physical paths or more complex component arrangements, thus improving learning capability while controlling device complexity.
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 system to perform learning and prediction tasks with high accuracy while maintaining a small size and low cost, as it effectively extends the delay time of the external feedback light, sustaining nonlinear input/output responses and reducing manufacturing complexity.
Implementation Method 1
a feedback waveguide that is operable to feed light output from the laser back to the laser
Implementation Method 2
a first ring resonator that is operable to be optically connected to the feedback waveguide
Data Source
AI summary
To realize a reservoir computing system with a small size and reduced learning cost, provided is a laser apparatus including a laser; a feedback waveguide that is operable to feed light output from the laser back to the laser; an optical splitter that is provided in a path of the feedback waveguide and is operable to output a portion of light propagated in the feedback waveguide to outside; and a first ring resonator that is operable to be optically connected to the feedback waveguide, as well as a reservoir computing system including this laser apparatus.