Optical Network Unit Dual Sideband Modulation for Bandwidth Efficiency
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Solution Overview
Problem
Conventional passive optical networks (PONs) face latency and throughput degradation due to the need for electronic processing and buffering in upstream data communication, which is costly and inefficient, especially in ultra-dense wavelength division multiplexing (UDWDM) systems requiring numerous individually modulated optical wavelengths.
Innovation Solution
The method employs dual sideband modulation in optical network units, allowing only one sideband to be processed at the terminal, enabling overlapping spectra to save bandwidth and using simple, cost-efficient components like OOK transmitters, eliminating the need for IQ-modulators and orthogonal hybrids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional PONs use electronic processing and buffering for upstream data communication, then data transmission can be achieved, but latency increases and throughput degrades
Solution Approach 1:
The patent replaces electronic processing and buffering systems with direct optical domain processing. Optical signals are processed and switched in the optical domain using optical cross-connects and optical buffers, eliminating the need for photo-detection, electronic buffering, and re-modulation. This substitution of mechanical/electronic systems with optical systems reduces latency and preserves throughput by maintaining signals in the optical domain throughout the switching process.
2Adaptability or versatility
If multiple discrete lasers are used to provide individual optical wavelengths for each user, then wavelength availability improves, but system cost and complexity increase significantly
Solution Approach 1:
The patent implements a universal optical buffer that can handle multiple wavelength channels simultaneously using a single optical cross-connect and optical buffer memory. Instead of requiring separate buffering infrastructure for each wavelength or user, the system provides multi-functional capability where one optical buffer can store and retrieve signals from multiple wavelength channels by controlling the optical switches. This universal approach reduces device complexity while maintaining adaptability for individual wavelength modulation.
3Ease of operation
If electronic processing is used for upstream data communication, then data routing is achieved, but system cost increases
Solution Approach 1:
The patent replaces electronic processing systems with optical domain processing systems. Optical cross-connects and optical buffers perform data routing and buffering functions directly in the optical domain, eliminating the need for photo-detection, electronic signal processing, and re-modulation. This substitution reduces system cost by removing expensive electronic processing components while maintaining full data routing capability through optical switching mechanisms.
4Productivity
If dense wavelength spacing is used to increase capacity, then bandwidth utilization improves, but signal distortion and crosstalk increase
Solution Approach 1:
The patent extracts and eliminates the sources of signal distortion and crosstalk by processing signals directly in the optical domain without conversion to electronic domain. By avoiding photo-detection and re-modulation, the system removes the primary sources of signal degradation that occur during electronic processing. Optical buffers and cross-connects handle dense wavelength multiplexed signals without introducing distortion, allowing high bandwidth utilization while maintaining signal quality through pure optical processing.
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 reduces occupied bandwidth, lowers costs by simplifying transmitter design, and enhances optical power efficiency by eliminating signal distortions and crosstalk, while maintaining high data rates in UDWDM systems.
Implementation Method 1
an optical network unit conveys data to a terminal via dual sideband modulation
Implementation Method 2
conveying optical data (via an optical network and at least one optical fiber)
Data Source
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AI summary
A method and a device for conveying optical data are provided, wherein an optical network unit conveys data to a terminal via dual sideband modulation, wherein the terminal processes only the upper or only the lower sideband received from the optical network unit, and wherein several dual sideband modulated signals from several optical network units partially overlap when being received at the terminal. Furthermore, a communication system is suggested comprising at least one such device.