ONU-Timed Optical Power Control for Equalized PON Uplink Bursts
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Solution Overview
Problem
The dynamic range problem in PON systems due to varying light powers from different optical network units (ONUs) leads to insufficient or excessive amplification, causing issues with OLT sensitivity and potential damage.
Innovation Solution
An optical signal power control method that involves acquiring arrival times of uplink optical signals, establishing a correspondence relationship between ONU IDs and power control factors, and adjusting gain or attenuation to equalize signal amplification to a receivable range by the OLT receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the SOA maintains the same gain for all ONUs, then the device complexity is reduced, but the receiving light power becomes insufficient for distant ONUs or excessive for near ONUs, causing OLT sensitivity issues or receiver overload
Solution Approach 1:
The patent implements dynamic gain adjustment for the SOA based on the distance between ONUs and the OLT. The system continuously monitors receiving light power and adjusts the SOA gain in real-time to optimize signal levels for different ONU positions, transforming the static single-gain approach into a dynamic adaptive system that maintains reliable reception across varying distances
Solution Approach 2:
The system changes the gain parameter of the SOA based on detected receiving light power levels. When light power is insufficient, the gain is increased; when light power is excessive, the gain is decreased. This parameter adjustment mechanism allows the same SOA to serve multiple ONUs at different distances effectively
2Productivity
If more users are added to the access network to increase bandwidth, then the productivity is improved, but the power budget becomes insufficient, requiring optical amplifiers and increasing device complexity
Solution Approach 1:
The SOA is designed to serve multiple functions: it amplifies signals for distant ONUs, attenuates signals for near ONUs, and adapts to varying network conditions. This multi-functional amplifier reduces the need for additional specialized components when expanding network capacity, allowing the same device to handle increased user loads through dynamic parameter adjustment rather than adding more hardware
3Reliability
If variable attenuation is added after the SOA to equalize emitting light power, then the receiving light power uniformity is improved, but the device complexity and cost increase
Solution Approach 1:
The patent combines the amplification function and the power control function into a single SOA device. Instead of having separate amplifiers and variable attenuators, the system uses one SOA with dynamic gain control that performs both functions - amplifying when needed and attenuating when needed - thereby reducing the total number of components while achieving uniform receiving light power across different ONUs
Data Source
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AI summary
Embodiments of the present disclosure provide an optical signal power control method and device, and an optical line terminal. The method includes: acquiring different time points when uplink optical signals of optical network units ONUs arrive at an optical signal amplifier or a variable optical attenuator; establishing a correspondence relationship between an ONU ID and a power control factor of the uplink optical signals; and performing power control on the uplink optical signals according to the different time points and the correspondence relationship. The embodiments of the present disclosure solve the equalization problem of equalizing uplink burst signal amplification in an optical network unit (ONU) in the related art, thereby achieving the technical effect of reducing requirements on the receiving power range of an OLT receiver.