Individually Routable Subcarriers in Optical Networks
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Solution Overview
Problem
Optical communication systems require multiple lasers and modulators to increase capacity, leading to increased costs and complexity, necessitating a more cost-effective solution with fewer components.
Innovation Solution
A digital signal processor generates Nyquist subcarriers from independent data streams, which are modulated by a single laser and modulator, allowing each subcarrier to carry data streams and be detected by separate receivers, reducing the need for multiple optical sources and improving network flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple lasers and modulators are used to increase system capacity, then the data transmission capacity is improved, but the system cost and complexity increase
Solution Approach 1:
The patent combines multiple optical carriers into a single multiplexed optical signal by merging multiple data streams onto one optical carrier using orthogonal frequency division multiplexing (OFDM). This allows a single laser and modulator to replace what would traditionally require multiple separate optical sources, thereby maintaining high data transmission capacity while reducing system complexity and cost.
Solution Approach 2:
The patent makes a single optical carrier perform multiple functions by enabling it to carry multiple independent data streams simultaneously through subcarrier multiplexing. The single optical carrier acts as a universal transmission medium that can be dynamically allocated to different data streams, replacing the need for dedicated optical sources for each data stream.
2Productivity
If multiple lasers and modulators are deployed to increase network capacity, then the data transmission capability is improved, but the network cost increases
Solution Approach 1:
The patent merges multiple data streams onto a single optical carrier using OFDM technology, where multiple subcarriers are modulated with different data streams and then combined. This consolidation reduces the number of physical components needed - specifically, one laser and one modulator can handle multiple data streams that would traditionally require multiple separate lasers and modulators.
Solution Approach 2:
The patent creates virtual copies of optical carriers through digital signal processing. Instead of physically duplicating optical sources, the system uses digital modulation to create multiple logical subcarriers from a single physical optical carrier. These virtual subcarriers can be independently addressed and routed, providing the functionality of multiple optical sources without the physical duplication.
3Quantity of substance
If a single laser and modulator are used to generate multiple subcarriers, then the network cost is reduced, but the difficulty of detecting and measuring individual data streams increases
Solution Approach 1:
The patent segments the single optical carrier into multiple orthogonal subcarriers in the frequency domain. Each subcarrier is assigned to carry a specific data stream and can be independently detected at the receiver. The orthogonal frequency division multiplexing structure allows the receiver to separate and detect each subcarrier's data stream through frequency-selective processing, making the detection process manageable despite the multiplexed nature of the signal.
Solution Approach 2:
The patent introduces digital signal processing as an intermediary layer between the optical transmission and data extraction. The receiver uses digital signal processing techniques including Fast Fourier Transform (FFT) to separate the multiplexed subcarriers and extract individual data streams. This digital intermediary simplifies the detection process by providing a systematic method to decode the multiplexed signal without requiring complex optical separation mechanisms.
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 approach reduces network costs and enhances flexibility by using a single laser and modulator to generate multiple subcarriers, enabling efficient data transmission across an optical communication network with fewer components.
Implementation Method 1
a laser and a modulator may be used to generate each optical signal
Implementation Method 2
a modulator that outputs a modulated optical signal based on the plurality of outputs
Data Source
AI summary
Consistent with an aspect of the present disclosure, electrical signals or digital subcarriers are generated in a DSP based on independent input data streams. Drive signals are generated based on the digital subcarriers, and such drive signals are applied to an optical modulator, including, for example, a Mach-Zehnder modulator. The optical modulator modulates light output from a laser based on the drive signals to supply optical subcarriers corresponding to the digital subcarriers. These optical subcarriers may be received by optical receivers provided at different locations in an optical communications network, where the optical subcarrier may be processed, and the input data stream associated with such optical subcarrier is output. Accordingly, instead of providing multiple lasers and modulators, for example, data is carried by individual subcarriers output from an optical source including one laser and modulator. Thus, a cost associated with the network may be reduced. Moreover, each of the subcarriers may be detected by a corresponding one of a plurality of receivers, each of which being provided in a different location in the optical communication network. Thus, receivers need not be co-located, such that the network has improved flexibility.