Optical Communication Frequency Control for Crosstalk Mitigation
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Solution Overview
Problem
Existing optical communication systems face challenges in accurately controlling wavelength intervals due to variations in bit error rates caused by nonlinear optical effects and crosstalk, leading to inaccurate wavelength adjustment in multiplexed optical signals.
Innovation Solution
The optical communication apparatus employs a frequency control method that calculates frequency offset and carrier frequency intervals using coherent detection and digital signal processing, allowing for precise adjustment of optical signal frequencies to maintain equally spaced intervals, thereby improving transmission accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If bit error rate is used to control wavelength intervals, then wavelength control can be implemented, but measurement precision deteriorates because bit error rate varies due to nonlinear optical effects and crosstalk in addition to channel crosstalk
Solution Approach 1:
The patent introduces an intermediary measurement method that uses optical spectrum analysis and frequency offset detection as intermediate steps between the received signal and the final wavelength control decision. Instead of directly using bit error rate, the system measures optical spectrum characteristics and frequency offsets as intermediate parameters that more accurately reflect channel crosstalk conditions, thereby resolving the contradiction between ease of operation and measurement precision.
2Adaptability or versatility
If wavelength-tunable light sources are used for optical transmission, then transmission flexibility is improved, but frequency stability deteriorates due to GHz-order frequency shift during long distance transmission
Solution Approach 1:
The patent implements a feedback mechanism where the receiving end detects frequency offsets and channel crosstalk conditions, then feeds back control signals to the transmitting end to adjust the wavelength-tunable light sources. This closed-loop feedback system maintains frequency stability despite the inherent drift of tunable light sources, while preserving their transmission flexibility through dynamic adjustment capabilities.
Solution Approach 2:
The patent dynamically changes operational parameters (wavelength, frequency offset compensation values) based on real-time detection results. By continuously adjusting these parameters in response to detected frequency shifts and crosstalk conditions, the system maintains both the adaptability of tunable light sources and their frequency stability during long-distance transmission.
3Productivity
If subcarriers are multiplexed at high density for superchannel technology, then transmission capacity is improved, but transmission performance deteriorates due to conspicuous crosstalk between carriers
Solution Approach 1:
The patent applies local quality optimization by individually detecting and compensating for crosstalk conditions in each subcarrier channel. Instead of treating all subcarriers uniformly, the system measures frequency offsets and crosstalk levels locally for each channel and applies targeted compensation, thereby maintaining high transmission capacity through dense multiplexing while improving overall transmission performance by addressing each channel's specific crosstalk characteristics.
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 enables high-accuracy control of wavelength intervals in multiplexed optical signals, enhancing transmission performance and reducing errors in long-distance optical communication systems.
Implementation Method 1
a frequency control unit, which calculates a frequency compensation amount of the optical signal to be transmitted on the basis of the frequency offset amount and the carrier frequency interval calculated by each transceiver
Data Source
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Figure 3~4
Figure 5
AI summary
An optical communication apparatus according to the present invention is an optical communication apparatus (103) that receives a signal in which optical signals each including multiplexed subcarriers are frequency multiplexed, and includes: transceivers (2-1 to 2-4) to perform reception process on a processing target band in which any one of the optical signals is included and to calculate a frequency offset amount between local light and a reception target optical signal that is an optical signal included in the processing target band and calculate a carrier frequency interval that is a frequency interval between the local light and an optical signal adjacent to the reception target optical signal; and a frequency control unit (6) to calculate an adjustment amount when an optical communication apparatus (101) that is a source of the optical signals adjusts the frequencies of the optical signals based on the frequency offset amount and the carrier frequency interval calculated by the transceivers (2-1 to 2-4) and to transmit the calculated adjustment amount to the optical communication apparatus (101) that is a source of the optical signals.