Optical Signal Transmission Using Wavelength Division Multiplexing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current optical signal transmission systems using VCSELs with multimode optical fibers experience performance degradation with increased signal modulation rates and transmission lengths, leading to interference between channels, especially in short-distance wavelength division multiplexing systems.
Innovation Solution
The system employs a short wavelength division multiplexer and demultiplexer with a signal processor that performs bit rate allocation and PAM4 modulation, using different wavelengths (1310 nm and 850 nm) to reduce interference by multiplexing and demultiplexing optical signals, and includes linear drivers and transmitters for amplification and offset addition, along with equalization processes to minimize bit error rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of wavelengths is increased to maintain transmission capacity, then the total transmission capacity is improved, but channel interference in the optical fiber increases
Solution Approach 1:
The patent changes the parameter of wavelength spacing by using widely spaced wavelengths (850nm and 1310nm) instead of closely spaced wavelengths. This parameter change reduces channel interference while maintaining transmission capacity through the use of only two wavelengths, thereby resolving the contradiction between transmission capacity and channel interference.
2Speed
If the signal modulation rate is increased to improve transmission speed, then the transmission rate is improved, but system performance degrades
Solution Approach 1:
The patent employs PAM4 (Pulse Amplitude Modulation with 4 levels) modulation which uses periodic signal patterns with distinct amplitude levels. This periodic action allows for reliable detection and reduces errors even at high transmission rates, thereby improving both speed and maintaining system performance.
Solution Approach 2:
The patent incorporates equalization technology that uses feedback mechanisms to compensate for signal degradation. The equalizer adjusts signal parameters based on detected errors and channel conditions, maintaining system performance at high transmission rates by continuously optimizing the signal quality.
3Length of stationary object
If the optical fiber transmission length is increased to extend transmission distance, then the coverage is improved, but system performance degrades
Solution Approach 1:
The patent changes the optical parameter by utilizing the 1310nm wavelength which has lower attenuation and dispersion characteristics in optical fibers compared to other wavelengths. This parameter change enables extended transmission distance while maintaining signal quality and system performance.
Solution Approach 2:
The patent employs equalization technology that provides feedback compensation for signal degradation over distance. The equalizer continuously adjusts signal parameters based on the actual channel conditions, maintaining reliable performance even over extended transmission distances.
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 the number of wavelengths transmitted, minimizing channel interference and maintaining transmission capacity, while reducing costs and crosstalk, and improving reliability by optimizing bit error rates and channel performance.
Implementation Method 1
the first transmitter is configured to convert the third electrical signal into a first optical signal and send the first optical signal to the short wavelength division multiplexer; the second transmitter is configured to convert the fourth electrical signal into a second optical signal
Implementation Method 2
the short wavelength division multiplexer is configured to multiplex the first optical signal and the second optical signal to the multimode optical fiber for transmission
Implementation Method 3
the short wavelength division demultiplexer is configured to demultiplex optical signals that are at different wavelengths and received from the multimode optical fiber into a first optical signal to be sent to the first linear receiver and a second optical signal
Implementation Method 4
the first linear receiver is configured to convert the first optical signal into a first electrical signal; the second linear receiver is configured to convert the second optical signal into a second electrical signal
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Embodiments of the present invention disclose an optical signal transmission method, apparatus, and system. The apparatus includes a short wavelength division multiplexer, a signal processor, a first linear driver, a second linear driver, a first transmitter, and a second transmitter. The signal processor is configured to perform bit rate allocation and code pattern modulation on a received binary signal, to obtain a first electrical signal to be sent to the first linear driver and a second electrical signal to be sent to the second linear driver. It can be learnt that, by implementing the embodiments of the present invention, a quantity of wavelengths transmitted in a multimode optical fiber can be reduced by performing bit rate allocation on a binary signal, thereby reducing interference between channels in the optical fiber for optical signal transmission.