Hybrid Tunable Laser Using Silicon Micro-Ring Filter
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Solution Overview
Problem
Existing tunable lasers for optical communication systems face challenges in achieving a wide wavelength range with narrow line-width and low intensity and phase noise, particularly in accurately aligning wavelengths to specified channel values and maintaining stability in power output.
Innovation Solution
A hybrid integrated adjustable external-cavity laser using a semiconductor optical amplifier chip, a grid filter, a phase adjuster, and a silicon-based micro-ring chip, which provides broadband gain, selective feedback, precise wavelength alignment, and low loss from free space to waveguide transmission, enabling multi-channel tuning and integration with a modulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If injection locking scheme is used to achieve wavelength tuning, then wavelength selection is enabled, but multi-FP cavity effect causes poor optical power stability
Solution Approach 1:
The patent extracts the problematic multi-FP cavity effect by replacing the injection locking scheme with an external cavity configuration using a grating filter and micro-ring resonator. This removes the source of optical power instability while preserving wavelength selection capability through the micro-ring's resonant filtering effect.
Solution Approach 2:
The patent introduces a micro-ring resonator as an intermediary element between the FP laser and the output. This mediator provides stable wavelength selection through its resonant properties without introducing the multi-cavity effects that cause power instability in direct injection locking schemes.
2Adaptability or versatility
If FP laser with multi-longitudinal-mode is used, then wide wavelength range is available, but it is difficult to accurately align to ITU-T wavelength channels
Solution Approach 1:
The patent applies local quality by using a micro-ring resonator with specifically designed resonant frequencies that match ITU-T wavelength channels. While the FP laser provides broad wavelength coverage, the micro-ring introduces localized resonant peaks at precise channel wavelengths, enabling accurate alignment without sacrificing overall wavelength range.
Solution Approach 2:
The patent changes the resonant frequency parameter of the micro-ring resonator to match specific ITU-T wavelength channels. By tuning the micro-ring's resonant characteristics, the system achieves precise wavelength alignment while maintaining the broad coverage capability of the underlying FP laser.
3Adaptability or versatility
If hybrid integration of III-V semiconductor gain chip and silicon-based chip is used, then laser generation is enabled in silicon-based technology, but device complexity increases
Solution Approach 1:
The patent merges the III-V semiconductor gain chip with the silicon-based micro-ring resonator and FP cavity into a hybrid integrated structure. This combination enables laser generation in silicon-based technology by leveraging the gain properties of III-V materials while utilizing silicon's advantageous waveguide and resonator structures, achieving functionality despite the inherent limitations of silicon's indirect band-gap.
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 achieves a tunable laser with a wide wavelength range, narrow line-width, and low noise, facilitating precise wavelength alignment and stability, while reducing module size and power consumption, expanding application in high-speed optical communication systems.
Implementation Method 1
When current is injected, the semiconductor optical amplifier chip generates stimulated emission
Implementation Method 2
The micro-ring filter achieves the die to silicon-based chip waveguide spot match by lens coupling
Implementation Method 3
An adjustable filter including a grid filter and a micro-ring filter provides, by the vernier effect, a selective feedback of an external-cavity longitudinal-mode corresponding to a desired wavelength
Data Source
AI summary
A wavelength-tunable external cavity laser comprises a semiconductor optical amplifier chip and a laser external cavity, the laser external cavity comprising a grid filter, a phase adjustor and a silicon-based micro-ring chip, the grid filter and the silicon-based micro-ring chip constituting a wavelength-tunable optical filter which implements wavelength tuning by spectral tuning of the grid filter and/or the silicon-based micro-ring chip. A micro-ring filter in the silicon-based micro-ring chip of the tunable external-cavity laser is manufactured by adopting a mature silicon light technology, which can greatly reduce a manufacturing difficulty of the adjustable filter, and reduce the manufacturing cost of a device. An existing external-cavity adjustable technology platform may be used for smooth transition, so as to improve the degree of integration of this type of device and simplify a preparation process.