Optical Transmission System Using Switching Unit for ASE Light Routing
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Solution Overview
Problem
In WDM optical transmission systems, the use of variable dispersion compensators like VIPA leads to a lowering of ASE light levels, making accurate gain setting for pre-amplifiers difficult, which degrades system quality due to wavelength periodicity effects.
Innovation Solution
An optical transmission system with a switching unit that selects a bypass route for noise light during booting mode and a passage route for signal dispersion compensation in working mode, using a switch controller to manage the routing based on monitoring control signals, ensuring ASE light levels are maintained for proper gain setting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a variable dispersion compensator (VIPA) is used to compensate chromatic dispersion in a WDM optical transmission system, then dispersion compensation accuracy is improved, but the ASE light level is lowered due to wavelength periodicity effects, making gain setting difficult
Solution Approach 1:
The optical path is segmented into two distinct routes: a passage route that includes the VIPA for dispersion compensation of signal light, and a bypass route that circumvents the VIPA for ASE light. This segmentation allows each route to be optimized for its specific function without interference from the other route's characteristics.
Solution Approach 2:
A switching unit acts as an intermediary device that dynamically routes optical signals based on their type. It receives input light, identifies whether it is signal light or ASE light, and directs it to the appropriate route (passage or bypass), thereby protecting the ASE light level while maintaining dispersion compensation for signal light.
2Ease of operation
If ASE light passes through the VIPA during system booting for gain setting, then the pre-amplifier can be initialized, but the wavelength periodicity of the VIPA distorts the ASE light spectrum, degrading system quality
Solution Approach 1:
The switching unit is configured to automatically select the bypass route during the system booting phase when ASE light is present, before signal light transmission begins. This preliminary routing decision prevents the VIPA from distorting the ASE light spectrum during the critical gain setting operation, ensuring system quality is maintained from the start.
Solution Approach 2:
The system dynamically switches between two operational modes: during booting, the bypass route is active to protect ASE light; during normal operation, the passage route is active for dispersion compensation. This dynamic adaptation allows the system to optimize performance for each operational phase without compromising overall reliability.
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 configuration allows for high-quality system booting using ASE light without harming gain settings and enables accurate dispersion compensation using VIPA, improving overall system performance.
Implementation Method 1
transmission speed of optical signals by optical fibers differs in every wavelength of light, chromatic dispersion causing a pulse waveform of light to be blunt occurs as transmission distance of light increases
Implementation Method 2
The VIPA is an optical device having a chromatic dispersion element (VIPA plate) obtained by coating both sides of a thin plate such as a glass plate with a reflection film and a reflection mirror
Implementation Method 3
The EDFA is an optical amplifier using an EDF (Erbium-dopped Fiber) as a medium for amplification in which an optical signal is made to travel by irradiating the EDF with pumping light and, by using stimulated emission occurring at the time of the irradiation, a level of an optical signal is amplified
Implementation Method 4
transmission distance is made longer and transmission capacity is made larger in an optical communication network
Data Source
AI summary
An optical transmission system is provided which is capable of booting the system by using an ASE (Amplified Spontaneous Emission) light in a manner to provide high quality. A pre-amplifier receives noise light and does gain setting in an amplifier booting mode and receives an optical signal and to amplify the received signal in a working mode. A variable dispersion compensator is placed in a preceding-stage of the pre-amplifier and makes compensation of dispersion of a wavelength occurring when an optical signal propagates through an optical fiber in a variable manner. A switching unit to select, when the noise light passes through the variable dispersion compensator, if a level of the noise light is deviated from a desired level, a bypass route so as to make the noise light not be input to the variable dispersion compensator but be input to the pre-amplifier in an amplifier booting mode according to a switching instruction and to select a passage route so as to make the optical signal, after having been input to the variable dispersion compensator and having undergone dispersion compensation, be input to the pre-amplifier according to the switching instruction in a working mode.