Pluggable Optical Transmitter Module With Pre-Distortion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hybrid fiber coaxial (HFC) networks face challenges in maintaining signal fidelity due to nonlinear responses of optical transmitters and optical fiber links, leading to intermodulation distortion, which affects the quality of high-resolution digital video and other communication signals.
Innovation Solution
A linearized optical transmitter unit with a directly or externally modulated laser, coupled with an electrical component that provides pre-distortion information to a direct digital synthesis engine, compensates for nonlinearities in the transmitter and fiber link, ensuring minimal added noise or distortion. This unit is integrated into a pluggable module for easy implementation in HFC systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pre-distortion is implemented to compensate for nonlinearities, then intermodulation distortion is reduced, but device complexity increases
Solution Approach 1:
The patent applies pre-distortion technology that performs preliminary compensation for nonlinearities in the optical transmitter and fiber link. By pre-compensating the signal before transmission, the system reduces intermodulation distortion without requiring complex real-time correction mechanisms, thus improving signal fidelity while controlling device complexity.
Solution Approach 2:
The patent introduces an intermediary processing stage that separates the distortion compensation function from the main transmission path. This intermediary layer handles the complex pre-distortion calculations independently, allowing the core transmitter to remain relatively simple while still achieving high signal fidelity through the mediating pre-distortion process.
2Ease of operation
If a pluggable module design is used, then ease of operation is improved, but manufacturing precision may be reduced
Solution Approach 1:
The patent divides the optical transmitter system into separate pluggable modules that can be independently manufactured, tested, and replaced. This segmentation allows each module to be optimized for its specific function while maintaining overall system performance through standardized interfaces and calibration procedures.
Solution Approach 2:
The patent employs parameter calibration and adjustment mechanisms that allow pluggable modules to be configured and optimized after installation. By enabling parameter changes such as pre-distortion coefficients and operating points, the system maintains high signal quality even with modular, easily replaceable components.
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 significantly reduces intermodulation distortion, enabling high-quality signal transmission with low noise across the frequency domain, while maintaining a low-cost, compact, and power-efficient design, suitable for widespread use in HFC networks.
Implementation Method 1
a directly-modulated or externally-modulated laser
Implementation Method 2
an externally-modulated laser
Data Source
AI summary
Linearized optical transmitter units are described for a hybrid optical fiber coaxial cable network. The linearized optical transmitter unit can comprise a directly-modulated or externally-modulated laser optically coupled to an optical conduit directed to an optical fiber communications link and electrically coupled to an electrical RF source line that provides an RF source to drive the laser or an external modulator for a light beam from the laser. A linearization information electrical component comprising memory and/or a processor, and a data output configured to transmit linearization enabling data for input into a direct digital synthesis engine that enables the direct digital synthesis engine to generate an RF signal wherein nonlinear responses of the transmitter and/or the optical fiber communications link are pre-compensated, in which the data is specific for the optical transmitter and/or the optical fiber communications link. An electronic communication channel can connected to the data output of the electrical component to communicate the linearization enabling data external to the linearized optical transmitter unit suitable for communication to the direct digital synthesis engine. The linearized optical transmitter can be assembled in a plug-in module. Corresponding HFC systems and methods are also described.