Optical Transmission Device Dummy Light Intensity Control
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Solution Overview
Problem
In optical submarine cable systems, the gain of optical amplifiers and optical loss due to transmission vary by wavelength, leading to intensity differences in wavelength-multiplexed optical signals, causing nonlinear effects and signal-to-noise ratio degradation. Existing techniques fail to appropriately suppress these effects by not accurately adjusting dummy lights in narrow bands.
Innovation Solution
An optical transmission apparatus that includes an optical signal adjustment unit, a dummy light output unit, and a control unit to adjust the intensity of dummy lights based on transmission line changes, ensuring each wavelength's intensity is balanced, thereby canceling out wavelength dependence and maintaining signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If dummy lights in narrow bands are used to maintain constant intensity, then intensity stability is improved, but the ability to flexibly adjust individual dummy light intensities deteriorates
Solution Approach 1:
The patent segments the dummy light control into individual adjustable units. Each dummy light is controlled independently through separate control signals, allowing flexible adjustment of individual dummy light intensities while maintaining overall intensity stability. This is achieved by dividing the control function into multiple independent control channels, one for each dummy light.
2Reliability
If pre-emphasis is applied to cancel wavelength dependence, then signal quality is improved, but the complexity of intensity adjustment increases
Solution Approach 1:
The patent applies pre-emphasis by adjusting the intensity of each dummy light before the optical signal transmission. The control unit calculates the required intensity adjustments based on wavelength-dependent characteristics and applies these adjustments in advance. This preliminary action compensates for expected signal quality degradation without requiring complex real-time adjustments during transmission.
3Adaptability or versatility
If multiple dummy lights are used to cover different wavelengths, then wavelength coverage is improved, but the difficulty of identifying and controlling specific dummy lights increases
Solution Approach 1:
The patent implements feedback control by monitoring the actual intensity of each dummy light and comparing it with the target intensity. The control unit receives feedback information about the optical signal characteristics and adjusts each dummy light's intensity accordingly. This closed-loop control system automatically identifies and controls the appropriate dummy lights without requiring manual intervention, even when multiple dummy lights are used across different wavelength bands.
Data Source
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AI summary
An object is to flexibly control a dummy light included in a wavelength-multiplexed optical signal and suppress degradation of signal quality. an optical signal adjustment unit (1) is configured in such a way that a plurality of optical signals with different wavelengths are input thereto, and adjusts an intensity of each of the plurality of optical signals based on an intensity change in a transmission line, and outputs the optical signals. A dummy light output unit (2) outputs a plurality of dummy lights (D) with different wavelengths, each dummy light having an intensity based on an intensity change in a transmission line. A control unit (4) identifies the dummy light corresponding to each of the optical signals, and controls the intensity of the identified dummy light based on the intensity of the optical signal corresponding to the identified dummy light and output from the optical signal adjustment unit (1). A multiplexing unit (3) outputs a wavelength-multiplexed optical signal (L) where the dummy light (D) and the optical signal (L10) output from the optical signal adjustment unit are combined.