Burst Mode Receiver Gain Switching for Wide Dynamic Range
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Solution Overview
Problem
Current burst mode receivers in passive optical networks are limited by their continuous automatic gain control method, which restricts dynamic range to around 20-25 dB, and has a long acquisition time, making them inadequate for handling the varying signal strengths and timings across different optical paths, especially when dealing with up to 60 dB variance.
Innovation Solution
A burst mode receiver with a combined architecture featuring high gain and adaptive gain circuitry portions, utilizing cascaded amplifiers and switches, and a peak detector to quickly switch between architectures based on input current ranges, allowing for a dynamic range of up to 60 dB and rapid signal acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If continuous automatic gain control method is used, then the receiver can tolerate fluctuations in input signal power, but the dynamic range is restricted to around 20-25 dB and acquisition time becomes long
Solution Approach 1:
The patent divides the continuous automatic gain control system into two separate gain control modes: high gain mode (for weak signals) and adaptive gain mode (for strong signals). This segmentation allows the receiver to handle a wider dynamic range (up to 60 dB) by selecting the appropriate mode based on signal strength, while maintaining fast acquisition time through direct switching between modes without the settling delays inherent in continuous systems.
2Measurement precision
If the transimpedance amplifier is designed for high gain to improve sensitivity, then weak signals can be detected, but the dynamic range is limited and cannot handle strong signals
Solution Approach 1:
The patent implements a dynamic gain control system that automatically switches between high gain mode and adaptive gain mode based on the detected signal strength. The peak detector monitors each incoming burst and controls switches to select the appropriate gain mode, enabling the receiver to maintain high sensitivity for weak signals while also handling strong signals within the same device, achieving a dynamic range of up to 60 dB.
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
The solution enables the receiver to handle a wide dynamic range of 60 dB with an acquisition time of less than 30 nanoseconds, supporting multiple optical network units at varying distances with high sensitivity and low bit error ratio, enhancing the efficiency and bandwidth of passive optical networks.
Implementation Method 1
a avalanche photodiode (APD), which converts the optical signal into an electrical current signal
Data Source
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AI summary
A burst mode receiver for a passive optical network includes a high gain circuitry portion having a plurality of cascaded amplifiers. The high gain circuitry portion also includes a plurality of high gain switches. The burst mode receiver further includes an adaptive gain circuitry portion having at least one inverter. The adaptive gain circuitry portion is configured to adaptively control the gain of the input signal. The adaptive gain circuitry portion further includes a plurality of adaptive gain switches. The high gain circuitry portion and the adaptive gain circuitry portion comprise a shared input portion. When a peak detector detects input current in a first range, the burst mode receiver is configured to activate the high gain circuitry portion, and when the peak detector detects input current in a second range, the burst mode receiver is configured to activate the adaptive gain circuitry portion.