Wavelength Division Multiplexing Filter for PON Coexistence

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Solution Overview

Problem

The existing Passive Optical Network (PON) systems, particularly GPON and XGPON1, face challenges in coexistence and require a wavelength division multiplexing filter that can accommodate different networks and integrate with an Optical Time Domain Reflectometer (OTDR) for real-time fault detection without service interruption.

Innovation Solution

A wavelength division multiplexing filter is designed to receive and split optical pulse signals across various wavelength ranges, enabling coexistence of GPON and XGPON1 systems and OTDR integration, using a combination of broadband and sideband filters or Fiber Bragg Grating filters to manage different wavelength bands, ensuring seamless communication and fault detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a wavelength division multiplexing filter is designed to support multiple PON systems (GPON and XGPON1) simultaneously, then the adaptability of the system is improved, but the device complexity increases

Engineering Contradiction:
Improvecompatibility with different PON systemsVSAvoidfilter structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The filter is divided into multiple functional modules: a first filter for GPON wavelength separation, a second filter for XGPON1 wavelength separation, and a third filter for OTDR wavelength separation. Each filter handles specific wavelength bands, allowing multiple PON systems to coexist without interference while maintaining manageable complexity through functional decomposition

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The wavelength division multiplexing filter serves multiple functions simultaneously: it separates wavelengths for GPON downlink and uplink, separates wavelengths for XGPON1 downlink and uplink, and provides OTDR interface wavelength separation. This multi-functional design allows a single device to support multiple PON systems and detection functions, improving adaptability without requiring separate filters for each system

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If an OTDR interface is integrated into the wavelength division multiplexing filter, then the ease of operation for network detection is improved, but the device complexity increases

Engineering Contradiction:
Improvenetwork detection convenienceVSAvoidfilter system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The OTDR interface function is merged into the wavelength division multiplexing filter by adding a third filter that separates the 1625nm OTDR wavelength from other PON wavelengths. This integration allows OTDR detection to be performed through the existing filter infrastructure without requiring separate detection equipment, improving ease of operation while keeping the added complexity minimal through efficient wavelength routing

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If wavelength multiplexing is implemented for different PON systems, then the productivity of the optical network is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveoptical network capacityVSAvoidwavelength separation precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

Each filter in the system is designed with specific local quality characteristics tailored to its function: the first filter is optimized for GPON wavelength ranges (1490nm downlink, 1310nm uplink), the second filter for XGPON1 wavelength ranges (1577nm downlink, 1270nm uplink), and the third filter for OTDR wavelength (1625nm). This localized optimization allows each component to meet precision requirements for its specific wavelength band while contributing to overall system productivity

Inventive Principle:
Principle #3Local quality

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 allows for the coexistence of different PON systems and real-time fault detection, reducing maintenance costs by ensuring uninterrupted service and efficient optical fiber management.

Implementation Method 1

the broadband filter transmits all light of a wavelength of 1290nm-1500nm, and reflects all light of other wavelengths

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

the side band filter transmits all light of a wavelength not less than 1625nm, and reflects all light of a wavelength less than this wavelength

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 3

a first window transmits all light of a wavelength of 1290nm-1360nm, and a second window transmits all light of a wavelength of 1480nm-1500nm, and reflects all light of other wavelengths

Methodology Applied
Scientific EffectBragg reflection: Bragg Diffraction

Data Source

PatentEP2475119B1Wavelength division multiplexing filter
Publication Date: 2016.03.30 ZTE CORP
  • EP2475119B1 patent drawingFigure 1~2
  • EP2475119B1 patent drawingFigure 3~4
  • EP2475119B1 patent drawingFigure 5~6

AI summary

The present invention discloses a Wavelength Division Multiplexing Filter which can satisfy coexistence requirements of different PON systems and an optical line detecting system. The Wavelength Division Multiplexing Filter comprises a plurality of filters that are configured: in a downlink direction, to receive a first optical pulse signal output by a first PON system, a second optical pulse signal output by a second PON system or gained by coupling an output signal of the second PON system and a video signal, and a third optical pulse signal sent from an Optical Time Domain Reflectometer, and to couple the first optical pulse signal, the second optical pulse signal and the third optical pulse signal into an Optical Division Network; and in an uplink direction, to split an uplink optical pulse signal according to wavelength bands, to transmit an optical pulse signal in a first uplink wavelength range to the first PON system, to transmit an optical pulse signal in a second uplink wavelength range to the second PON system, and to transmit an optical signal in a third uplink wavelength range to the Optical Time Domain Reflectometer.