Wavelength Selective Coupler for Optical Grating Demultiplexor
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Solution Overview
Problem
Current WDM-PON systems, such as those using arrayed waveguide (AWG) WDM de/multiplexors, lack independent selection of wavelengths for channels directed to the same output port, limiting bandwidth utilization and network efficiency, especially in FTTP applications where cost-effective broadband coverage is essential.
Innovation Solution
An optical device with offset input ports for an optical grating demultiplexor allows independent routing of wavelength channels to the same output port, utilizing a wavelength selective coupler and optical grating demultiplexor to separate and demultiplex channels, enabling adjustable wavelength selection and increased channel spacing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single input port WDM de/multiplexor is used to direct multiple wavelength channels to the same output port, then device complexity is reduced and cost is saved, but independent wavelength selection is lost and bandwidth utilization is limited
Solution Approach 1:
The single input port is segmented into multiple offset input ports (first input port and second input port), each handling different wavelength channels. This segmentation allows independent wavelength selection while maintaining a relatively simple device structure, resolving the contradiction between device complexity and adaptability.
Solution Approach 2:
The patent introduces a spatial dimension offset between input ports to enable wavelength differentiation. By positioning input ports at different locations (offset by a specific distance), the system can independently select and direct different wavelength channels to the same output port, enhancing adaptability without significantly increasing device complexity.
2Productivity
If wavelength channels are closely spaced to maximize bandwidth utilization, then bandwidth utilization improves, but wavelength separation becomes difficult and channel crosstalk increases
Solution Approach 1:
The patent applies preliminary spatial separation by offsetting input ports before the wavelengths enter the demultiplexor. This preliminary action creates an initial wavelength separation that facilitates subsequent demultiplexing, allowing closely spaced wavelengths to be effectively separated without requiring extremely high manufacturing precision.
Solution Approach 2:
The offset input ports act as an intermediary mechanism that facilitates wavelength separation. By introducing this intermediate spatial offset, the system can handle closely spaced wavelength channels more effectively, reducing the demand on manufacturing precision while maintaining good wavelength separation and minimizing crosstalk.
3Adaptability or versatility
If multiple separate WDM de/multiplexors are used for each wavelength channel, then independent wavelength selection is achieved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple input port functions into a single demultiplexor device. By combining the wavelength separation and demultiplexing functions into one integrated device with multiple offset input ports, the system achieves independent wavelength selection without requiring multiple separate de/multiplexors, thus reducing device complexity and cost.
Solution Approach 2:
The single demultiplexor device is designed to handle multiple wavelength channels simultaneously through its multiple offset input ports. This multi-functional design allows one device to perform the work of multiple separate devices, achieving independent wavelength selection while maintaining simplicity and cost-effectiveness.
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 solution enhances bandwidth utilization and network efficiency by allowing independent selection of wavelengths, reducing deployment costs for FTTH-based broadband Internet services by simplifying channel management and increasing wavelength separation.
Implementation Method 1
a wavelength selective coupler having an input port and first and second output ports, for separating wavelength channels received at the input port into first and second groups of wavelength channels
Implementation Method 2
an optical grating demultiplexor having first and second input ports optically coupled to the first and the second output ports of the wavelength selective coupler, respectively, and a plurality of output ports, for demultiplexing the first and the second groups of wavelength channels
Implementation Method 3
wherein the first and the second input ports of the optical grating demultiplexor are offset from each other so as to couple a wavelength channel of the first group from the first input port, together with a wavelength channel of the second group from the second input port, into a same output port of the optical grating demultiplexor
Data Source
AI summary
An optical device for rearranging wavelength channels in an optical network is disclosed. The optical device has a wavelength selective coupler having one input port and a plurality of output ports coupled to a plurality of input ports of an optical grating demultiplexor such as an arrayed waveguide grating. The wavelength channels in each of the input ports are dispersed by the demultiplexor and are directed to a plurality of output ports of the optical grating demultiplexor. As a result, at least one wavelength channel at each of the input ports of the optical grating demultiplexor is coupled into a common output port. The optical device is useful in passive optical networks wherein a same demultiplexor is used for simultaneous multiplexing and demultiplexing of wavelength channels.