Optical Channel Power Detection Across Mixed Frequency Grids
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Solution Overview
Problem
Current signal detection methods for WDM systems face challenges in accurately detecting optical power for each channel, especially when frequency grids with different center frequency intervals coexist, leading to complex wire connections, erroneous signal recognition, and inadequate detection capabilities.
Innovation Solution
A signal detection device and method that utilize a signal detection unit to compare data from transmitters with data from an OCM, employing a variable wavelength filter and photo diode to measure optical power at specific sampling points, allowing for accurate detection across different frequency grids by adjusting the sampling interval and recognizing power at adjacent frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Tap-PD array is used to detect optical signals for each channel, then signal detection capability is improved, but wire connection complexity and circuit size increase significantly
Solution Approach 1:
The patent combines multiple detection functions into a single OCM device that can measure optical power across multiple channels simultaneously. Instead of using separate Tap-PDs for each channel, the OCM integrates wavelength separation and power measurement functions in one unit, dramatically reducing wire connections and circuit complexity while maintaining detection capability.
Solution Approach 2:
The OCM is designed as a universal detection device that can handle multiple wavelength channels and different frequency grids (50 GHz, 37.5 GHz, 25 GHz) with a single unit. This multi-functional approach eliminates the need for channel-specific detectors and reduces overall system complexity.
2Ease of operation
If a fixed frequency grid is used for WDM signal detection, then detection simplicity is improved, but adaptability to different center frequency intervals deteriorates
Solution Approach 1:
The OCM incorporates a tunable wavelength filter that can dynamically adjust its center frequency and bandwidth to match different frequency grids (50 GHz, 37.5 GHz, 25 GHz). This dynamic adjustment capability allows the same detection device to adapt to various channel configurations without requiring hardware changes, maintaining both simplicity and versatility.
Solution Approach 2:
The system changes operational parameters (filter center frequency, filter bandwidth, measurement wavelength) based on the detected frequency grid type. By programmatically adjusting these parameters, the OCM can accurately detect signals across different WDM configurations while maintaining a unified detection approach.
3Productivity
If wavelength division multiplexing is used to increase transmission capacity, then system capacity is improved, but signal detection accuracy for each channel deteriorates due to spectral overlap
Solution Approach 1:
The OCM internally segments the WDM spectrum by using a tunable wavelength filter to isolate individual channel wavelengths before measurement. By sequentially tuning the filter to each channel's specific wavelength and measuring power at that isolated wavelength, the system achieves accurate per-channel detection even in high-capacity WDM systems with closely spaced channels.
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
Enables accurate detection of optical power for each channel in WDM signals with varying frequency grids, reducing errors and complexity, and ensuring reliable signal interruption alarms.
Implementation Method 1
a power measurement value obtained by measuring power of a WDM (wavelength division multiplexing) signal
Data Source
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AI summary
In the present invention, in order to detect the optical power of each channel of a WDM signal in which frequency grids having different central frequency intervals coexist, a signal detection device is provided with: a comparison unit that obtains data including central frequencies of optical signals respectively transmitted by a plurality of optical transmitters and a central frequency interval indicating the interval between the central frequencies, power measurement values obtained by measuring, at sampling point frequencies arranged at a prescribed sampling interval, the power of a WDM signal for which the wavelength of optical signals has been multiplexed, a sampling interval, and sampling point frequencies, that selects a selection value from among the power measurement values on the basis of the central frequency interval and the sampling interval, and that outputs a result of comparison between the selection value and a prescribed threshold; and an alarm generator that outputs a signal interruption alarm in a case where the comparison result indicates that the selection value is less than the threshold.