Optical Transceiver Spectral Compression Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current optical transceivers in metro-access networks face performance limitations due to optical reflections and high costs, particularly with coherent interfaces that require tunable lasers and complex receiver structures, and existing solutions like Ultra Dense Wavelength Division Multiplexing (UDWDM) are costly and inefficient.
Innovation Solution
The implementation of a transceiver system that uses Spectral Compression Modulation (SCM) techniques to separate downstream and upstream signals in the RF spectrum, allowing for low-cost components and improved performance by filtering and modulating signals within specific frequency bands, thereby reducing bandwidth and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If coherent optical interfaces with tunable lasers are used to achieve long link distance, then link distance is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent replaces expensive coherent receivers with direct detection receivers that use simple photodiodes and basic signal processing. The system achieves long-distance transmission by using spectrally compressed signals with bandwidth below Nyquist frequency, allowing standard low-cost components to achieve performance previously requiring complex coherent interfaces.
Solution Approach 2:
The patent changes the spectral parameters of the optical signals by compressing them below the Nyquist frequency. This parameter change allows the use of simple direct detection receivers while maintaining long link distance, as the compressed spectral width enables efficient signal separation and detection without requiring complex receiver structures.
2Productivity
If Ultra Dense Wavelength Division Multiplexing (UDWDM) is used to increase channel density, then spectral efficiency is improved, but cost increases significantly
Solution Approach 1:
Instead of increasing wavelength density in the optical domain (UDWDM approach), the patent moves to the RF spectrum domain and uses spectral compression to achieve high spectral efficiency. By compressing signals in the RF domain below Nyquist frequency and using separate RF spectrum parts for different signals, the system achieves high channel density with standard cost components.
3Device complexity
If standard optical transmission is used, then system simplicity is maintained, but performance is limited by optical reflections and relative intensity noise
Solution Approach 1:
The patent changes the temporal and spectral parameters of the optical signals by compressing them below the Nyquist frequency. This creates spectrally compressed signals that are more resistant to optical reflections and relative intensity noise, improving signal quality while maintaining system simplicity through direct detection.
Solution Approach 2:
The patent applies spectral compression to the signals before transmission, pre-conditioning them to be more robust against reflections and noise. This preliminary spectral shaping ensures that the signals arrive at the receiver with improved quality, reducing the need for complex equalization or compensation techniques.
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 results in a reflection-tolerant, spectrally efficient optical transmission system that reduces costs and increases link distance and spectral efficiency, utilizing low-cost components and binary modulation formats for both upstream and downstream signals.
Implementation Method 1
a modulator configured to modulate the same optical carrier with a second signal in a second part of the RF spectrum
Implementation Method 2
a receive part configured to receive and detect a first signal carried on an optical carrier
Data Source
AI summary
A transceiver (4) comprising a receive part (70) configured to receive and detect a first signal carried on an optical carrier, wherein the signal is in a first part of a RF spectrum. The transceiver (4) further comprises a modulator (68) configured to modulate the same optical carrier with a second signal in a second part of the RF spectrum. The transceiver comprises a transmit part (60) configured to transmit the optical carrier modulated with the second signal. The first part of the RF spectrum is separate to the second part of the RF spectrum. The first signal and/or second signal are spectrally compressed signals.