Fast Tunable Hybrid Laser with Silicon-Photonic Switch
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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 restricted by silicon thermal tuner response, which is not fast enough for sub-microsecond optical switching.
Innovation Solution
A tunable laser design incorporating a reflective silicon optical amplifier (RSOA) with an array of narrow-band reflectors and a 1×N silicon-photonic optical switch, allowing frequency tuning by selectively coupling the input port to different output ports, forming a lasing cavity with a selected narrow-band reflector, and including a phase tuner for fast frequency adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If silicon thermal tuner is used for wavelength tuning, then wavelength tuning capability is achieved, but switching speed is limited to microseconds
Solution Approach 1:
The system segments the wavelength tuning function into two independent parts: a fast silicon-photonic switch for rapid wavelength selection and a III-V gain medium for light amplification. This segmentation allows the switching function to operate independently at nanosecond speeds without being constrained by thermal tuning limitations.
Solution Approach 2:
The patent replaces the thermal-mechanical tuning mechanism with an optical switching mechanism. Instead of using heat to change refractive index and tune wavelength, the system uses optical switches to rapidly select different wavelength paths, achieving nanosecond-scale switching speeds.
2Use of energy by moving object
If III-V gain chip is integrated with silicon photonic chip, then wall-plug efficiency is improved, but device complexity increases
Solution Approach 1:
The patent merges the III-V gain chip and silicon photonic chip into a hybrid integrated system where the III-V material provides efficient light generation and the silicon photonic structures provide wavelength-selective feedback. This combination achieves high wall-plug efficiency by leveraging the complementary strengths of both materials.
Solution Approach 2:
The hybrid laser structure serves multiple functions simultaneously: the III-V gain medium provides optical amplification, the silicon photonic switch enables rapid wavelength tuning, and the distributed Bragg reflectors provide wavelength-selective feedback. This multi-functionality is achieved within a single integrated device architecture.
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 fast, sub-microsecond wavelength switching with minimal impairment to wall-plug efficiency, supporting multi-polarization and enhancing the applicability of silicon-photonic switches in optical networks.
Implementation Method 1
a reflective silicon optical amplifier (RSOA) having a reflective end and an interface end... causing the RSOA to form a lasing cavity with a selected narrow-band reflector
Implementation Method 2
reflective silicon optical amplifier (RSOA)
Implementation Method 3
an array of N narrow-band reflectors, wherein each narrow-band reflector in the array has a different center wavelength... each output port is coupled to a different narrow-band reflector
Implementation Method 4
an optical waveguide that couples the interface end of the RSOA to the input of the 1×N silicon-photonic optical switch
Data Source
AI summary
A tunable laser includes a reflective silicon optical amplifier (RSOA) with a reflective end and an interface end and an array of narrow-band reflectors, which each have a different center wavelength. It also includes a silicon-photonic optical switch, having an input port and N output ports that are coupled to a different narrow-band reflector in the array of narrow-band reflectors. The tunable laser also includes an optical waveguide coupled between the interface end of the RSOA and the input of the silicon-photonic optical switch. The frequency of this tunable laser can be tuned in discrete increments by selectively coupling the input port of the silicon-photonic optical switch to one of the N output ports, thereby causing the RSOA to form a lasing cavity with a selected narrow-band reflector coupled to the selected output port. The tunable laser also includes a laser output optically coupled to the lasing cavity.