Optical Receiver Bandwidth Expansion Using Low-Speed APDs

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Solution Overview

Problem

Current optical transmission systems face challenges in maintaining high-speed data transmission rates due to the limitations of avalanche photo diodes (APDs), particularly in achieving sufficient bandwidth and cost-effectiveness for high-speed optical receivers, especially in long-distance or high-capacity networks.

Innovation Solution

Implementing a high-speed optical receiver using a low-speed APD with a frequency characteristic compensation circuit, a transimpedance amplifier (TIA), and a post amplifier, along with adjusting the APD bias voltage, to expand the frequency bandwidth and meet the requirements for 10 Gb/s transmission rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a high-speed APD is used to achieve 10 Gb/s transmission rate, then the bandwidth is sufficient, but the manufacturing difficulty and cost increase significantly

Engineering Contradiction:

Improvetransmission rateVSAvoidmanufacturing difficulty

Core Design Contradiction:

SpeedVSEase of manufacture

Solution Approach 1:

The patent uses low-speed APDs (originally designed for 2.5 Gb/s) instead of expensive high-speed APDs, treating the low-speed components as adequate substitutes that can be manufactured easily and in large quantities, sacrificing the need for specialized high-speed components

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the operating parameters of the low-speed APD by adjusting the bias voltage and adding frequency compensation circuits, transforming the frequency response characteristics to enable 10 Gb/s operation without changing the physical structure or manufacturing process of the APD itself

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the transmission rate is increased to 10 Gb/s or more, then the transmission capacity increases, but the APD bandwidth becomes insufficient

Engineering Contradiction:

Improvetransmission capacityVSAvoidAPD bandwidth

Core Design Contradiction:

ProductivityVSSpeed

Solution Approach 1:

The patent introduces frequency compensation circuits as intermediary components between the low-speed APD and the high-speed transmission system, acting as a mediator that bridges the bandwidth gap by electronically compensating for the frequency response limitations of the low-speed APD

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent makes the system dynamically adjustable by implementing bias voltage control and frequency compensation that can be tuned to optimize performance for different transmission rates, allowing the low-speed APD to adapt to high-speed operation through dynamic parameter adjustment

Inventive Principle:

Principle #15Dynamics

3Ease of manufacture

If a low-speed APD is used to reduce cost, then manufacturing becomes easier, but the frequency bandwidth is insufficient for high-speed transmission

Engineering Contradiction:

Improvemanufacturing easeVSAvoidfrequency bandwidth

Core Design Contradiction:

Ease of manufactureVSSpeed

Solution Approach 1:

The patent changes the electrical parameters of the low-speed APD system by adjusting bias voltage and adding frequency compensation, transforming the frequency response to achieve high-speed performance while maintaining the use of easily manufactured low-speed components

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent makes the low-speed APD serve multiple functions by enabling it to operate at both its native low speed and at high speeds through parameter adjustment, allowing a single component design to fulfill multiple transmission rate requirements

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 the optical receiver to achieve the necessary reception sensitivity and bandwidth for 10 Gb/s PON systems, reducing manufacturing costs and overcoming the limitations of existing APDs, while maintaining optimal performance.

Implementation Method 1

gain is obtained in photoelectric conversion

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Implementation Method 2

a transimpedance amplifier (TIA) for amplifying a signal received from the APD to have low noise

Methodology Applied

Scientific EffectTransimpedance amplification:

Implementation Method 3

a post amplifier for amplifying the signal to a signal with an amplitude available in a digital element

Methodology Applied

Scientific EffectSignal amplification:

Data Source

PatentUS9455790B2High-speed optical receiver implemented using low-speed light receiving element and method for implementing the same

Publication Date: 2016.09.27 SOLUTIONS SARL

AI summary

A high-speed optical receiver implemented using a low-speed light receiving element is provided, which is configured to receive an optical signal having a higher transmission rate than that received using a general avalanche photo diode (APD) by expanding a frequency bandwidth using a receiver circuit configured together with an APD in the optical receiver including the APD, an APD bias control circuit, a transimpedance amplifier (TIA) for amplifying a signal received from the APD to have low noise, and a post amplifier; and a method of implementing such a high-speed optical receiver.