Tunable Laser with Silicon-Photonic Switch for Sub-Microsecond Wavelength Selection
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Solution Overview
Problem
Existing silicon-photonic MEMS-based optical switches support only single polarization, limiting their application in optical networks, and current wavelength-tunable hybrid lasers have switching times limited by silicon thermal tuners, which are not fast enough for sub-microsecond optical switching.
Innovation Solution
A tunable laser design incorporating a set of reflective silicon optical amplifiers (RSOAs) and narrow-band reflectors, integrated with a silicon-photonic optical switch, allowing for fast wavelength switching by forming a lasing cavity with a selected narrow-band reflector, and utilizing directional couplers and phase tuners for efficient frequency adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If silicon thermal tuner is used for wavelength tuning, then the hybrid laser can be implemented, but the wavelength tuning speed is limited to microseconds
Solution Approach 1:
The patent replaces the thermal tuning mechanism with a silicon-photonic MEMS-based optical switch that uses mechanical micromirrors for wavelength selection. This substitution eliminates the slow thermal diffusion process and achieves sub-microsecond switching speeds through rapid mechanical mirror positioning.
Solution Approach 2:
The patent changes the tuning mechanism from thermal parameter adjustment to optical path selection using MEMS mirrors. By changing the physical parameter from temperature-based tuning to mechanical position-based routing, the system achieves faster wavelength switching.
2Speed
If single polarization silicon-photonic MEMS optical switch is used, then fast switching can be achieved, but the application in optical networks is limited
Solution Approach 1:
The patent designs the hybrid laser system to work with multiple polarization states by integrating both horizontally and vertically polarized gain media. The MEMS optical switch is configured to handle multiple polarization modes, making the system universally applicable to diverse optical network requirements.
Solution Approach 2:
The patent segments the gain media into multiple polarization-specific sections (horizontal and vertical polarization gain chips) that can be independently optimized. Each segment can be tuned to different wavelengths while maintaining polarization diversity, allowing the system to support multiple polarization states simultaneously.
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
Enables sub-microsecond wavelength switching with improved scalability and redundancy, overcoming the limitations of single polarization support and slow switching times in existing technologies, facilitating high-performance optical interconnects and networking systems.
Implementation Method 1
a set of M reflective silicon optical amplifiers (RSOAs)... causing a RSOA coupled to the selected amplifier port to form a lasing cavity
Implementation Method 2
N narrow-band reflectors... a lasing cavity with a wavelength, which is determined by a center wavelength of the narrow-band reflector
Implementation Method 3
a silicon-photonic optical switch, having M amplifier ports, which are coupled through a set of M optical waveguides to the set of M RSOAs
Data Source
AI summary
The disclosed embodiments provide a tunable laser that includes a set of M reflective silicon optical amplifiers (RSOAs) and a set of N narrow-band reflectors. It also includes a silicon-photonic optical switch, having M amplifier ports, which are coupled through a set of M optical waveguides to the set of M RSOAs, and N reflector ports, which are coupled to the set of N narrow-band reflectors. The tunable laser also includes a switching mechanism that facilitates coupling at least one selected amplifier port from the M amplifier ports with a selected reflector port from the N reflector ports, thereby causing an RSOA coupled to the selected amplifier port to form a lasing cavity with a narrow-band reflector coupled to the selected reflector port. The tunable laser also includes a laser output, which is optically coupled to the lasing cavity.