APD Burst-Mode Receiver Bias Control for Overcurrent Protection

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Solution Overview

Problem

The existing bias voltage control methods for burst-mode receivers in PON systems face challenges in maintaining constant automatic gain control, stability of photocurrent, and high-speed response, particularly when dealing with short packets and variable optical input power, which affects monitoring and signal regeneration.

Innovation Solution

A burst-mode receiver configuration that includes a current detection circuit, a peak detector circuit, and a resistor connection switching circuit, allowing for high-speed voltage changes applied to the APD while maintaining stable photocurrent, using a series resistor only when necessary to reduce photocurrent and prevent overcurrent.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the multiplication factor M of the APD is set to be high to improve receiving sensitivity for low optical input power, then receiving sensitivity is improved, but the risk of overcurrent breaking down the APD increases when high optical input power is received

Engineering Contradiction:

Improvereceiving sensitivityVSAvoidovercurrent risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The multiplication factor M of the APD is dynamically adjusted based on the detected optical input power level. When low optical power is detected, a high multiplication factor is applied to improve receiving sensitivity. When high optical power is detected, the multiplication factor is reduced to prevent overcurrent. This dynamic adaptation resolves the contradiction between maximizing receiving sensitivity and preventing overcurrent damage.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system employs a feedback mechanism where the optical input power is continuously monitored and used to control the multiplication factor of the APD. The detected optical power level feeds back to the control circuit, which adjusts the multiplication factor accordingly. This closed-loop feedback system ensures that the APD operates at optimal sensitivity without risking overcurrent damage.

Inventive Principle:

Principle #23Feedback

2Speed

If the multiplication factor M is changed at high speed of the order of nanosecond to enable burst-mode reception, then burst-mode reception capability is achieved, but the stability of photocurrent and automatic gain control output becomes difficult to maintain

Engineering Contradiction:

Improvemultiplication factor change speedVSAvoidphotocurrent stability

Core Design Contradiction:

SpeedVSStability of the object's composition

Solution Approach 1:

The system performs preliminary detection of the optical input power level before the actual burst signal arrives. The peak detector circuit prepares the multiplication factor setting in advance based on the detected power level, so that when the burst signal arrives, the APD is already configured with the appropriate multiplication factor. This preliminary action allows high-speed response while maintaining photocurrent stability during the actual reception.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The reception process is segmented into distinct phases: a detection phase where optical power level is measured and multiplication factor is set, and a reception phase where the actual burst signal is received with the pre-configured multiplication factor. This segmentation allows the system to optimize for both speed (by pre-setting parameters) and stability (by maintaining constant multiplication factor during reception).

Inventive Principle:

Principle #1Segmentation

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 configuration enables stable and high-speed voltage control for the APD, ensuring reliable signal regeneration and monitoring, even with high optical input power, while maintaining a simple circuit configuration and preventing overcurrent issues.

Implementation Method 1

an avalanche photodiode (APD) is used. Because the APD has a function of multiplying a photocurrent

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

a peak detector circuit for detecting and holding a peak value of an output voltage of the current detection circuit

Methodology Applied

Scientific EffectPeak detection:

Implementation Method 3

a comparator for outputting a switching signal for switching the resistor connection switching circuit so that a series resistor is connected to the reversely connected APD in series

Methodology Applied

Scientific EffectVoltage comparison:

Data Source

PatentUS9525495B2Burst-mode receiver, and method of bias voltage control for APD of burst-mode receiver

Publication Date: 2016.12.20 MITSUBISHI ELECTRIC CORP

AI summary

A burst-mode receiver for receiving burst optical signals having different intensities by a reversely connected APD, including: a current detection circuit outputting a photocurrent that is generated by APD and is output from a current mirror circuit (CMC) as a voltage proportional to the photocurrent, the CMC being connected in series between a power supply and APD; a peak detector circuit detecting and holding a peak value of the output voltage of the current detection circuit; a resistor connection switching circuit, which is inserted between the CMC and APD, for connecting a series resistor to APD in series by switching; and a comparator outputting a switching signal for switching the resistor connection switching circuit so that the series resistor is connected to APD in series in a case where a voltage detected by the peak detector circuit is equal to or more than a predetermined threshold.