Edge-Shaped Waveguide Laser Decoupling Bragg Gratings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing silicon photonics-based DBR lasers have limited tunability range and are bulky due to constraints in design and production methods, with heat dissipation and power consumption issues, and lack flexibility in grating design.
Innovation Solution
The laser device decouples length selectivity by physically de-correlating the two Bragg gratings, allowing for shorter and less bulky designs with increased reflectivity, achieved by orienting the ridge waveguide and forming Bragg gratings with different pitches and etching depths on opposite faces, enabling wider tunability and efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the first grating and the second grating of a sampled Bragg reflector are produced by superposition on the same face in a semiconductor layer, then the laser can achieve wavelength tuning, but the device becomes longer and bulkier with limited design freedom
Solution Approach 1:
The patent applies dimensionality change by moving the second Bragg grating from the same face (2D superposition) to the opposite face (3D separation) of the semiconductor layer. This spatial reconfiguration allows the gratings to be physically decoupled while maintaining their optical functionality, thereby reducing the device length and bulk without compromising wavelength tuning capability.
Solution Approach 2:
The patent segments the sampled Bragg reflector by separating the first and second gratings into different faces of the semiconductor layer. This segmentation enables independent optimization of each grating's parameters (pitch, length, etching depth) and allows the use of different manufacturing processes for each grating, thus reducing overall device complexity and length.
2Adaptability or versatility
If heating elements are placed close to the Bragg gratings to modify refractive index for wavelength tuning, then wavelength can be tuned towards higher frequencies, but the tunability range is limited to less than 20nm and heat dissipation becomes problematic
Solution Approach 1:
The patent changes the physical parameters of the Bragg gratings themselves (pitch, length, etching depth) rather than relying solely on thermal effects. By fabricating gratings with different pitches on opposite faces, the device achieves wavelength tuning through geometric parameter variation, which is more efficient and has a broader tuning range than thermal refractive index modulation alone.
Solution Approach 2:
The patent extracts the wavelength tuning function from the heating elements and transfers it to the geometric design of the Bragg gratings. By taking out the thermal management requirement from the core tuning mechanism, the device achieves broader tuning range with reduced heat dissipation issues.
3Adaptability or versatility
If the pitch of the second Bragg grating is larger than the first grating to add reflection peaks, then wider wavelength tuning range is achieved, but the reflectivity of the second grating decreases requiring longer grating lengths
Solution Approach 1:
The patent uses dimensionality change by placing the second grating on the opposite face with increased etching depth. This vertical dimension compensation offsets the reduced reflectivity caused by the larger pitch, allowing the second grating to maintain sufficient reflectivity while providing the desired wavelength tuning range.
Solution Approach 2:
The patent applies local quality by optimizing each grating's parameters according to its specific function: the first grating has a smaller pitch for high reflectivity, while the second grating has a larger pitch for wavelength tuning, with compensating etching depth adjustments to maintain adequate reflectivity locally at each grating position.
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 approach results in DBR lasers with enhanced tunability, reduced bulk, and improved reflectivity, making them more suitable for telecommunications by allowing greater design freedom and efficient operation.
Implementation Method 1
a first Bragg grating having a first pitch and produced by etching in the ridge and a second Bragg grating having a second pitch, different from the first pitch, and produced by etching on the face of the ribbon waveguide opposite the ridge
Implementation Method 2
by placing a heating element close to the Bragg gratings and by precisely increasing the temperature at the level of the Bragg gratings by applying a current to the heating elements, the refractive index of silicon is modified by the temperature variation
Data Source
Figure 1~2
Figure 3A~3C
Figure 4~5
AI summary
The invention relates to a laser device (1) disposed in and/or on silicon and with a III-V heterostructure, comprising: • a III-V heterostructure gain medium (3), and • an edge-shaped optical waveguide (11), disposed opposite the gain medium (3) and comprising a ribbon waveguide (15) having a longitudinal edge (17), the edge-shaped optical waveguide (11) being disposed in silicon, • two sets of Bragg gratings (RBE-A, RBE-B) formed in the edge-shaped optical waveguide (11) and disposed on either side of the III-V heterostructure gain medium (3), each set of Bragg gratings (RBE-A, RBE-B) comprising a first Bragg grating (RB1-A, RB1B) having a first pitch and formed in the edge (17) and a second Bragg grating (RB2-A, RB2-B) having a different second pitch of the first step and formed on the face (21) of the ribbon waveguide (15) opposite the edge (17).