Optical Transmission Compensation for Pass-Band Narrowing
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Solution Overview
Problem
Signal deterioration occurs due to pass-band narrowing (PBN) in optical relay nodes, leading to increased peak-to-average power ratio (PAPR) and signal quality degradation in optical communication systems.
Innovation Solution
An optical transmission system with optical elements that compensate for signal deterioration based on predetermined compensation amounts determined by measuring the optical signal spectrum at specific positions before and after the transmission path, using optical elements like semiconductor optical amplifiers and rotational density filters, without converting the signal to electrical form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital signal processing circuit of optical transmitter emphasizes high frequency region to compensate for pass-band narrowing, then signal waveform deterioration is compensated, but rising of signal waveform becomes steep and overshoot increases leading to new deterioration
Solution Approach 1:
The patent replaces electrical signal processing with optical signal processing. Instead of using digital signal processing circuits to emphasize high frequency regions, the invention uses optical elements (optical filters, optical amplifiers) to perform equalization and compensation directly in the optical domain, thereby avoiding the generation of overshoot and electrical noise associated with electrical compensation methods
Solution Approach 2:
The patent introduces optical elements as intermediaries between the optical transmitter and optical relay nodes. These optical elements (such as optical equalizers and optical amplifiers) serve as mediators to compensate for pass-band narrowing effects without converting the optical signal to electrical form, thus avoiding the harmful effects of electrical noise and overshoot
2Reliability
If electrical compensation is applied to compensate for signal deterioration in transmission path, then signal waveform is restored, but electrical noise and nonlinear response cause new signal deterioration
Solution Approach 1:
The patent substitutes electrical compensation mechanisms with optical compensation mechanisms. By using optical elements to perform equalization and signal restoration directly in the optical domain, the system eliminates the introduction of electrical noise and nonlinear response artifacts that occur during electrical-to-optical conversion and processing
3Productivity
If high-density wavelength multiplexing is implemented to increase transmission capacity, then communication capacity increases, but pass-band narrowing occurs at optical relay nodes causing signal deterioration
Solution Approach 1:
The patent maintains continuous optical signal processing throughout the transmission path without interruption by electrical conversion. Optical amplifiers and optical equalizers continuously compensate for signal deterioration caused by pass-band narrowing at optical relay nodes, ensuring signal quality is maintained even in high-density wavelength multiplexing systems with increased transmission capacity
Data Source
AI summary
An optical transmission system using a transmission path for transmitting an optical signal, including: a transmitter for transmitting the optical signal; one or more optical elements for compensating deterioration of the optical signal; and a receiver for receiving the optical signal, in which a compensation amount of each of the optical element for the degradation is a predetermined amount based on a spectrum of the optical signal at a first measurement position that is a predetermined position between the transmitter and the transmission path and a spectrum of the optical signal at a second measurement position that is a predetermined position between the transmission path and the receiver.