Single-Laser Bidirectional Optical Processing for Free-Space Links
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical communication systems for data centers face challenges with high installation and maintenance costs, immobility, and high outage probability due to fiber-related faults, especially in modular data centers, while free-space optical links suffer from atmospheric attenuation and turbulence, leading to complex architectures and inefficient data transmission.
Innovation Solution
A bi-directional optical communication system using a single laser source with a combination of modulation schemes, including differential quadrature phase shift keying (DQPSK) and On-Off keying (OOK), employs a simplified architecture to transmit high data rates over turbulent free-space optical channels, utilizing components like Mach-Zehnder modulators, electro-absorption modulators, and wavelength converters to enhance data transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If optical fibers are used for long-reach inter-data center interconnects, then transmission distance is improved, but installation cost and deployment time increase significantly
Solution Approach 1:
The patent replaces the mechanical fiber optic installation system with a free-space optical transmission system using lasers and telescopes. This eliminates the need for physical fiber laying, drilling, and complex mechanical connections, thereby reducing installation costs and deployment time while maintaining long transmission distances.
Solution Approach 2:
The patent extracts the optical transmission function from the physical fiber medium and implements it through free-space optical paths. By removing the fiber optic cable requirement, the system eliminates installation complexity while preserving the core function of long-distance data transmission between data centers.
2Reliability
If optical fibers are deployed for data center interconnects, then transmission stability is improved, but mobility and adaptability decrease
Solution Approach 1:
The patent transitions from a static fiber optic connection to a dynamic free-space optical system. The laser and telescope assemblies can be moved, repositioned, and reconfigured without permanent installation, enabling modular data centers to adapt their connectivity as business requirements change while maintaining stable transmission through controlled optical paths.
Solution Approach 2:
The free-space optical transmission system serves multiple functions: it provides stable long-distance transmission like fiber optics, enables mobility and repositioning, and allows rapid deployment and reconfiguration. This multi-functionality resolves the contradiction between stability and adaptability by combining features that were previously mutually exclusive.
3Adaptability or versatility
If conventional free-space optical links are used, then mobility and rapid deployment are improved, but atmospheric turbulence causes signal degradation
Solution Approach 1:
The patent acknowledges atmospheric turbulence as an inevitable harm in free-space optical transmission but converts this challenge into an acceptable trade-off by demonstrating that the mobility and rapid deployment benefits outweigh the signal quality issues. The system accepts some signal degradation as a necessary cost for achieving true mobility and flexibility in modular data center configurations.
4Reliability
If multiple separate optical sources are used for bidirectional transmission, then transmission reliability is improved, but system complexity and cost increase
Solution Approach 1:
The patent merges the functions of multiple separate optical sources into a single laser source that handles bidirectional transmission. By combining the transmission functions and using wavelength division or time-division multiplexing, the system reduces component count and simplifies the architecture while maintaining reliable bidirectional communication between data centers.
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 system achieves high data rates with cost-efficiency and reduced component count, overcoming atmospheric turbulence and fiber-related issues, enabling flexible and rapid deployment of data centers with simplified detection techniques.
Implementation Method 1
The at least two MZM are configured to phase modulate the at least two optical pulsed signals using the at least two differentially encoded electrical signals to provide a first phase modulated optical pulsed signal and a second phase modulated optical pulsed signal
Implementation Method 2
The EAM is configured to amplitude modulate the processed optical pulsed signal using the third electrical signal to provide a phase-amplitude modulated optical pulsed signal
Implementation Method 3
The optical amplifier is configured to amplify the pulse-amplitude modulated optical pulsed signal and generate a transmitter optical pulsed signal for transmission
Implementation Method 4
The photodetector is configured to convert the first optical pulsed signal into a first electrical signal with two amplitude levels corresponding to the third channel in the first transmitter
Data Source
AI summary
A bi-directional optical communication system employing a minimum number of single-mode high repetition rate pulsed optical signal sources to achieve cost efficiency while maintaining high data rates. The bi-directional optical communication system includes a first optical data processing unit and a second optical data processing unit. The first optical data processing unit modulates a pulsed optical source using a differential quadrature phase shift keying (DQPSK) modulation and two-level pulse amplitude (PAM-2) modulation and then demodulates it to achieve a pulse amplitude modulated signal. The second optical data processing unit reuses the same optical carrier by passing it through a regenerative wavelength converter to generate three pulsed optical carriers at different wavelengths and employs an On-off keying (OOK) modulation scheme. These carriers are employed to send uplink data at a same rate of as the downlink. As a result, large data is transmitted from one data center to another data center through a downlink and uplink free space optical link network.