Optical Transmitter Micro-Ring Filtering Multiplexing
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Solution Overview
Problem
Existing optical transmitters for high-speed and long-distance optical communications, such as those using directly modulated lasers, face challenges with size and cost due to the need for multiple discrete elements for spectrum shaping and wavelength division multiplexing, which complicates integration and increases packaging costs.
Innovation Solution
An optical transmitter design incorporating a directly modulated laser array and a micro-ring group array, where each directly modulated laser is coupled with a circular waveguide group and a first waveguide, with a second waveguide aggregating signals and a feedback control circuit adjusting resonant wavelengths to optimize signal extinction ratios, reducing the number of elements and transmitter size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple discrete elements are used for spectrum shaping and wavelength division multiplexing, then transmission performance is improved, but device size and complexity increase
Solution Approach 1:
The patent combines multiple discrete optical elements (filter, wavelength division multiplexer, modulator) into a single integrated optical chip. The micro-ring resonator array performs both filtering and wavelength division multiplexing functions simultaneously, while the Mach-Zehnder modulator integrates modulation capability, eliminating the need for separate discrete elements and reducing overall device complexity while maintaining transmission performance
Solution Approach 2:
The micro-ring resonator array serves multiple functions: it acts as a spectral filter for the directly modulated laser, performs wavelength division multiplexing for multiple channels, and enables coherent detection. This multi-functional integration replaces what would traditionally require separate discrete components, reducing device size and complexity
2Reliability
If multiple discrete elements are optically coupled using free space, then spectral filtering is achieved, but integration difficulty and packaging costs increase
Solution Approach 1:
The patent replaces free-space optical coupling (mechanical alignment system) with waveguide-based optical coupling. All optical elements are connected through integrated waveguides on the chip, eliminating the need for precise free-space alignment and reducing packaging complexity. The waveguide system provides robust, alignment-free optical coupling
3Reliability
If a multi-cavity filter is added after DML, then chirping control and transmission distance are improved, but optical module size increases
Solution Approach 1:
The patent implements a compact nested structure where micro-ring resonators are integrated within the optical chip alongside the laser and modulator. The micro-ring filters are coupled to waveguides in a nested configuration, allowing spectral filtering functionality to be embedded within the existing optical path without requiring additional external space, thus controlling chirping while maintaining a compact module size
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 design effectively reduces the size and cost of optical transmitters while maintaining high-speed and long-distance transmission capabilities, enabling efficient multi-channel transmission and optimizing signal processing through integrated filtering and multiplexing.
Implementation Method 1
each circular waveguide group is configured to couple a part of optical signals from the first waveguide corresponding to the circular waveguide group to the second waveguide
Implementation Method 2
a feedback control circuit adjusting resonant wavelengths to optimize signal extinction ratios
Data Source
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AI summary
Embodiments of the present invention disclose an optical transmitter and an optical transmission method. An embodiment of the present invention includes a directly modulated laser array and a micro-ring group array, where the directly modulated laser array may output multiple channels of optical signals, each directly modulated laser is correspondingly provided with one circular waveguide group and one first waveguide, each circular waveguide group may couple a part of optical signals output by a directly modulated laser corresponding to the circular waveguide group to a same second waveguide, and the second waveguide aggregates optical signals from circular waveguide groups and outputs an aggregated optical signals. The micro-ring group array implements not only filtering but also multiplexing, which effectively reduces a quantity of elements, reduces a size of an optical transmitter, and reduces costs.