RoF Node EML Frequency Generation Reduces Complexity
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Solution Overview
Problem
Current Radio-over-Fiber (RoF) communication systems face challenges in achieving high data transmission rates and bandwidth while minimizing transmission losses, especially when using millimeter wave or terahertz waves, due to high costs and complexity associated with integrating high-frequency components like mixers and local oscillators.
Innovation Solution
The proposed multiband RoF communication system employs Electroabsorption Modulated Lasers (EMLs) of different wavelengths to generate high-frequency signals without the need for mixers or local oscillators, utilizing optical couplers and photodetectors for frequency conversion, thereby reducing system complexity and cost, and enabling operation across multiple frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional coaxial cables are used to transmit data, then transmission infrastructure is established, but transmission losses are high
Solution Approach 1:
The patent replaces traditional coaxial cable transmission with optical fiber transmission. The mechanical/electrical system of coaxial cables is substituted with an optical system using lasers and fiber optics, achieving lower transmission losses while maintaining infrastructure functionality.
Solution Approach 2:
The patent introduces optical fiber as an intermediary medium between the base station and central platform. This intermediary enables data transmission with lower losses compared to direct coaxial cable connections, solving the transmission loss problem while establishing a new transmission infrastructure.
2Productivity
If millimeter wave or terahertz wave is used for transmission, then data transmission rate increases, but transmission losses increase
Solution Approach 1:
The patent substitutes millimeter wave/terahertz wave transmission with optical carrier transmission. By using optical frequencies instead of millimeter waves, the system achieves high data transmission rates through the fiber medium without suffering from the high transmission losses inherent in millimeter wave propagation.
Solution Approach 2:
The patent transitions from radio frequency transmission (millimeter wave) to optical frequency transmission. This dimensional change in the electromagnetic spectrum enables high-speed data transmission while avoiding the propagation losses associated with millimeter waves, as optical signals are confined to the fiber medium.
3Adaptability or versatility
If mixers and local oscillators are integrated for high-frequency signal generation, then frequency conversion capability is achieved, but system complexity and cost increase
Solution Approach 1:
The patent extracts and removes the mixers and local oscillators from the system architecture. By using direct optical modulation with EMLs, the frequency conversion function is achieved without these traditional RF components, thereby reducing system complexity and cost while maintaining adaptability.
Solution Approach 2:
The patent introduces EMLs as an intermediary device that directly modulates optical carriers with RF signals. This intermediary eliminates the need for separate mixers and local oscillators, achieving frequency conversion capability through a simpler, more integrated approach.
4Productivity
If high-frequency carriers are used for data transmission, then data transmission rate increases, but system complexity increases
Solution Approach 1:
The patent merges the functions of signal generation, modulation, and frequency conversion into a single integrated EML device. By combining these functions, the system achieves high data transmission rates without the complexity of separate high-frequency components, as the EML directly generates modulated optical signals.
Solution Approach 2:
The patent replaces complex RF signal generation and modulation systems with direct optical modulation using EMLs. This substitution eliminates the need for multiple high-frequency components and their associated control circuits, achieving high data rates with reduced system complexity.
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 allows for efficient, low-cost, and easy integration of high-frequency signals, reducing transmission losses and increasing the distance data can be transmitted, while supporting multiple frequency bands without the need for mixers or local oscillators, thus enhancing the overall system's cost-effectiveness and integration ease.
Implementation Method 1
a laser source which transmits a first laser beam having a first wavelength
Implementation Method 2
a first Electroabsorption Modulated Laser (EML) which transmits a second laser beam having a second wavelength that is modulated by the first electrical signal
Implementation Method 3
a first photodetector (PD) which is coupled to the first optical splitter, receives the first optical signal, and converts the first optical signal into a first electrical signal
Data Source
AI summary
The disclosure is directed to a radio over fiber (RoF) network node, base station, and communication system. In one of the exemplary embodiments, the disclosure is directed to a radio over fiber (RoF) network node which includes not limited to: a laser source which transmits a first laser beam having a first wavelength; a first Electroabsorption Modulated Laser (EML) which modulates a first electrical signal into a second laser beam that is modulated and has a second wavelength; and a first optical coupler which is coupled to the laser source and the EML and transmits an output laser beam having a first carrier frequency which is determined based on a difference between the first wavelength and the second wavelength.