Silicon Tunable Filter Using MZI-MRR Cascades for Stable Wavelength Tuning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The spectrum of silicon-based external cavity tunable lasers is easily affected by manufacturing process and environmental variations, impacting laser regulation and stability.
Innovation Solution
A silicon-based tunable filter and laser design incorporating a flat-top band-pass filter, Mach-Zehnder interferometry, and micro ring resonation structures on a silicon substrate, with asymmetric tunable phase shift arms and cascaded configurations to achieve tunable narrowband filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dual micro-ring resonators with different FSR are used to achieve wide tuning range, then the wavelength selection capability is improved, but the spectrum becomes highly sensitive to manufacturing process and environmental variations
Solution Approach 1:
The patent employs asymmetric Mach-Zehnder interferometer arm lengths to create a fixed frequency comb spectrum that is insensitive to manufacturing variations. The asymmetric design establishes a deterministic interference pattern that stabilizes the optical frequency comb generation, resolving the sensitivity issue while maintaining wide tuning capability through the asymmetric path difference
Solution Approach 2:
The patent introduces an optical frequency comb as an intermediary between the light source and the tunable filter. This frequency comb acts as a stable reference that mediates the wavelength selection process, enabling precise tuning while being robust against manufacturing and environmental variations through its fixed spectral structure
2Adaptability or versatility
If radii of dual micro-ring resonators are made close to ensure sufficient tuning range, then the wavelength coverage is improved, but the spectrum becomes easily affected by small radius changes
Solution Approach 1:
The patent replaces the mechanical/physical micro-ring resonator system with an optical frequency comb generation system based on asymmetric Mach-Zehnder interferometry. This substitution eliminates the sensitivity to radius variations by using optical path difference in the interferometer arms, which can be precisely controlled and is less susceptible to manufacturing tolerances
Solution Approach 2:
The patent changes the controlling parameter from physical radius dimensions of micro-rings to optical path length differences in the Mach-Zehnder interferometer. This parameter transformation allows for more precise control and stability, as the interferometric path difference can be accurately defined and maintained without the same sensitivity to fabrication variations
3Ease of manufacture
If silicon-based external cavity chip with dual micro-ring resonators is used, then integration with CMOS process is achieved, but the laser regulation and stability are easily affected by manufacturing and environment
Solution Approach 1:
The patent segments the tunable filter function into two independent components: an optical frequency comb generator (asymmetric MZI) and a tunable filter (single micro-ring or other structures). This segmentation allows each component to be optimized independently - the comb generator provides stability while the filter provides tuning capability, both being manufacturable with CMOS-compatible processes
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
Ensures high integration, low power consumption, and stable single-peak narrowband filtering, overcoming manufacturing and environmental sensitivity issues.
Implementation Method 1
The interference effect of the Mach-Zehnder interferometry structure and the resonance effect of the micro ring resonation structure are superimposed on an optical signal
Implementation Method 2
The interference effect of the Mach-Zehnder interferometry structure and the resonance effect of the micro ring resonation structure are superimposed on an optical signal
Implementation Method 3
the filtering effect of the flat-top band-pass filter structure is also act on the optical signal, which forms a tunable narrowband filtered optical signal to output
Data Source
AI summary
Provided are a silicon-based tunable filter, laser and an optical module. The tunable laser comprises a semiconductor optical amplifier and a silicon photonic integrated chip, wherein a first coupler, a phase regulator and a tunable filter are provided on the silicon photonic integrated chip; the tunable filter comprises a flat-top band-pass filter structure, a Mach-Zehnder interferometry (MZI) structure and a micro ring resonation (MRR) structure, which are cascaded; gain light emitted by the semiconductor optical amplifier is coupled to the silicon photonic integrated chip by means of the first coupler, and a narrowband filtered optical signal is output by means of the tunable filter; and the phase of the gain light is regulated by means of the phase regulator so as to output single-peak narrowband laser light with a tunable target wavelength.