Optical Receiver Module Distortion Compensation
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Solution Overview
Problem
Existing optical receiver modules face challenges in reducing transmission penalty due to waveform distortion in long-distance optical transmission systems, particularly due to increased size, power consumption, and cost associated with variable dispersion compensators and band-pass filters, and the need for additional FEC functions or components like LSI chips.
Innovation Solution
The optical receiver module employs input signal amplitude and light power monitors to detect distortion levels, adjusting threshold and phase values optimally to minimize transmission penalty without the need for variable dispersion compensators or band-pass filters, using a block diagram configuration with a light receiving element, preamplifier, clock extraction circuit, and phase adjusting circuits to maximize receiver sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a variable dispersion compensator is used to suppress waveform distortion, then transmission penalty is reduced, but device complexity and size increase
Solution Approach 1:
The patent extracts the essential function of waveform distortion compensation from complex variable dispersion compensators and implements it through simple threshold value adjustment based on distortion level detection. This separates the core compensation function from the bulky hardware components, achieving distortion suppression without increasing module size.
Solution Approach 2:
The patent changes the operating parameter (threshold value) of the decision circuit based on the detected distortion level. By dynamically adjusting the threshold value according to the distortion level calculated from input signal amplitude and light power, the system compensates for waveform distortion without adding complex hardware.
2Reliability
If a variable dispersion compensator is used to suppress waveform distortion, then transmission penalty is reduced, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive variable dispersion compensators with inexpensive threshold adjustment mechanisms. The distortion level detection uses existing monitor circuits (input signal amplitude monitor and light power monitor) that are already present in the module, avoiding the need for additional costly components.
3Reliability
If FEC function is added to the optical transceiver module for code error monitoring, then waveform distortion compensation is enabled, but power consumption increases
Solution Approach 1:
The patent enables the optical transceiver module to perform waveform distortion compensation using its own existing resources - the input signal amplitude monitor and light power monitor circuits. By calculating distortion level from these existing monitors and adjusting the threshold value accordingly, the module achieves error correction functionality without requiring external FEC circuits or additional power-consuming components.
4Reliability
If a band-pass filter is added to the optical transceiver module for distortion compensation, then transmission penalty is reduced, but device complexity and cost increase
Solution Approach 1:
The patent extracts the essential distortion compensation function from the band-pass filter structure and implements it through threshold value adjustment. This removes the need for additional filter components while maintaining the core functionality of suppressing transmission penalty through distortion level-based threshold optimization.
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 improves the transmission penalty characteristic by dynamically adjusting threshold and phase values based on distortion levels, reducing the module's size, power consumption, and cost while maintaining high receiver sensitivity.
Implementation Method 1
a light receiving element (31) which receives the optical signal and performs optic-electric signal conversion to the signal
Data Source
AI summary
A relation between a light input power monitor value of an optical transmission signal before passing through a fiber and an input signal amplitude monitor value is recorded in advance in a storage device. Next, actual optical-transmission-waveform is inputted into an optical receiver module, and then comparisons between a light input power monitor value and an input signal amplitude monitor value, and respective monitor values in the case without having the waveform distortion as described above are performed in an operation device to calculate a waveform distortion value. According to the waveform distortion level calculated herein, an optimum threshold value and an optimum phase adjusting value, at which receiver sensitivity is maximized, are calculated in the operation device to control a threshold-value adjusting circuit and a phase-value adjusting circuit, thereby a threshold value and a phase value that are optimum for an input distortion level can be established.