Directly Modulated Laser With Microring Resonator For Eye Diagram
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Solution Overview
Problem
Existing directly modulated lasers face challenges in achieving a clear optical eye diagram during high-speed modulation, leading to difficulties in decision and recovery at the receiving end, and existing solutions are bulky and difficult to integrate.
Innovation Solution
The use of two microring structures with the same structure and parameter settings to implement mode selection and filtering, improving device integration and achieving a good optical eye diagram.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a directly modulated laser is used for high-speed modulation, then modulation speed is improved, but the optical eye diagram quality deteriorates (nearly closed)
Solution Approach 1:
An external optical filter is introduced as an intermediary component between the directly modulated laser and the optical receiver. This filter compensates for the chirp-induced spectral broadening and distortion, thereby improving the optical eye diagram quality without reducing the modulation speed of the laser itself.
Solution Approach 2:
The filtering function is extracted from the laser device itself and placed as a separate external component. This allows the laser to maintain its high-speed modulation capability while the external filter handles the signal quality improvement, resolving the contradiction between speed and quality.
2Reliability
If an external filter is used to improve optical eye diagram, then optical eye diagram quality is improved, but device size increases and integration becomes difficult
Solution Approach 1:
The optical filter is merged with the laser device to form an integrated structure. The filter is designed to be compatible with the laser's packaging and mounting interface, allowing the filtering function to be incorporated without significantly increasing the overall device size or complexity, thus enabling better integration while maintaining optical eye diagram quality.
3Ease of operation
If amplitude modulation is used to control laser output, then modulation simplicity is improved, but optical eye diagram quality deteriorates during high-speed modulation
Solution Approach 1:
The external optical filter acts as a mediator that corrects the output of simple amplitude modulation. By filtering out unwanted spectral components and reducing chirp effects, the filter enables simple amplitude modulation to achieve high-quality optical eye diagrams without requiring complex modulation schemes.
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 enhances device integration and produces an optical eye diagram with a good effect, improving the extinction ratio and representation of the optical eye diagram.
Implementation Method 1
according to a chirp effect of a directly modulated laser, functions of mode selection and filtering are implemented by using two microring structures with the same structure and similar parameter settings
Data Source
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AI summary
In the field of optical networks, a laser, a laser modulation method and a laser combination system are disclosed. The laser (1) includes a gain medium (11), a resonator (12), and a second microring resonator (13), where the resonator (12) includes a first cavity mirror (121), and a second cavity mirror (122), the first cavity mirror (121) is located at one port of the gain medium (11), the second cavity mirror (122) is located at the other port of the gain medium (11), and the second cavity mirror (122) includes a splitter (1221), a first microring resonator (1222), and a reflecting grating (1223). Embodiments of the present invention resolve problems that it is difficult to resolve an optical eye diagram of output by an existing directly modulated laser due to limited performance of the laser during high-speed modulation and that it is difficult to integrate the laser.