Optical Signal Processing Device for Power Measurement Error Correction
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Solution Overview
Problem
In digital coherent optical receivers, selecting a baud rate lower than the maximum can lead to measurement errors in the power of a predetermined optical channel due to the inclusion of adjacent channel signal components, which affects the accuracy of power measurement.
Innovation Solution
A signal processing device with a first conversion circuit to convert electric field signals from time domain to frequency domain, a filter circuit to narrow the passband, a second conversion circuit to convert back to time domain, and an amplitude measurement circuit to correct measurement errors by notifying a power measurement device with individual amplitudes, thereby reducing the impact of adjacent channel components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a lower baud rate is selected to reduce measurement errors from adjacent channel components, then measurement precision improves, but productivity decreases
Solution Approach 1:
The patent segments the frequency spectrum by applying a filter with a passband narrower than the receiving bandwidth. This separates the predetermined channel signal from adjacent channel components, allowing accurate power measurement of the target channel even when using a lower baud rate that captures broader frequency content.
Solution Approach 2:
The patent extracts the harmful adjacent channel components from the received signal by using a filter that selectively passes only the frequency range of the predetermined channel. This extraction allows the system to measure power accurately without the interference of other channels, resolving the contradiction between measurement precision and productivity.
2Adaptability or versatility
If the receiving bandwidth is widened to capture more signal components, then adaptability improves, but measurement precision deteriorates due to inclusion of adjacent channel components
Solution Approach 1:
The patent divides the received signal into frequency segments using a filter with a narrower passband than the full receiving bandwidth. This segmentation allows the system to maintain wide receiving capability for adaptability while isolating the specific channel of interest for precise power measurement, eliminating the contradiction between adaptability and measurement precision.
Solution Approach 2:
The filter acts as an intermediary between the wide receiving bandwidth and the precise measurement requirement. It selectively passes the frequency components of the predetermined channel while blocking adjacent channel components, enabling both wide adaptability and precise measurement simultaneously.
3Measurement precision
If a narrower passband filter is applied to isolate the predetermined channel, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent uses a filter that creates a narrowed passband copy of the frequency spectrum, selectively passing only the predetermined channel frequencies. This copying approach allows precise power measurement of the target channel while the filter structure itself handles the complexity, making the solution practical despite the increased device complexity.
Solution Approach 2:
The patent changes the frequency parameter by applying a filter with a narrower passband than the receiving bandwidth. This parameter change isolates the predetermined channel from adjacent channels, improving measurement precision. The complexity is managed through standard filter implementation techniques that modify only the frequency response characteristics.
Data Source
AI summary
A signal processing device includes: a first conversion circuit that, among optical signals of channels included in wavelength division multiplexed optical signal, converts electric field signals that indicate electric field components of the optical signal of a predetermined channel, from time domain signals into frequency domain signals; a filter that passes the electric field signals converted into the frequency domain signals with a passband; a second conversion circuit that converts the electric field signals, from the frequency domain signals into the time domain signals; an amplitude measurement circuit that measures first amplitudes of the electric field signals and second amplitudes of the electric field signals; and a notification circuit that notifies a power measurement device that measures power of the optical signal of the predetermined channel, of the first amplitudes and the second amplitudes used in correction of a measurement error of the power of the optical signal.