27 Oct The race to 1.6Tb/s
As technology evolves, the volume of data being generated and transmitted is growing exponentially. This is driven by a variety of applications, including high-definition and 4K/8K video streaming, virtual reality, augmented reality, and massive datasets used in scientific research, artificial intelligence, and machine learning. To handle these data loads, higher data rates are necessary. In data centers, the need for high data rates is critical to support the rapid exchange of data between servers, storage devices, and networking equipment. This is essential for providing low-latency and high-throughput services to users and applications. IoT is an emerging technology that connects a vast number of devices to the internet, generating a massive amount of data. High data rates are needed to handle the data traffic from billions of interconnected devices efficiently. These, and many other applications, are driving the need for higher optical transport networks to 1.6Tb/s and beyond.
1.6Tb/s will be enabled by coherent pluggables and digital signal processing
Coherent pluggable transceivers, in conjunction with advanced digital signal processing (DSP) techniques, have revolutionized the world of high-speed data communication by enabling unprecedented data rates of 100Gb/s, 400Gb/s, 800Gb/s, and even 1.6Tb/s. This remarkable achievement in optical communication technology has transformed the way we transmit and receive data, making it possible to meet the ever-increasing demands of today’s data-hungry world.
Coherent pluggable transceivers utilize advanced modulation schemes, such as quadrature amplitude modulation (QAM), to encode data onto laser light. These transceivers leverage the principles of coherent detection, which allows for the precise recovery of data even in the presence of signal distortions and noise. By doing so, they extend the reach and capacity of optical networks, enabling data rates that were previously thought to be unattainable.
Digital signal processing is a key enabler for these high data rates. The DSP algorithms applied at both the transmitter and receiver ends play a critical role in mitigating impairments in the optical channel. They compensate for issues like chromatic dispersion, polarization mode dispersion, and non-linear effects, ensuring that the received signal remains coherent and discernible. This technology has ushered in a new era of reliability and efficiency in optical networks.
The role of standards: IEEE approach to 1.6Tb/s development
In the realm of contemporary networking applications, the prevailing standard for Ethernet speed tops out at 400 Gigabits per second (Gb/s). Nevertheless, the IEEE 802.3 2020 Ethernet Bandwidth Assessment has emphasized that by 2025, an array of applications spanning servers, data center networks, mobile networks, and telecom networks will witness bandwidth growth rates ranging from 2.3 to 55.4 times the traffic levels observed in 2017.
To confront this impending challenge, the IEEE 802.3 Ethernet Working Group has adopted a bifurcated strategy employing two distinct task forces. These task forces are dedicated to ushering in Ethernet solutions exceeding the 400 Gb/s threshold:
The IEEE P802.3df Task Force will harness the existing 100 Gb/s per lane electrical and optical signaling technologies. Their goal is to introduce 800 Gb/s Ethernet capabilities, with a focus on electrical interfaces and physical layer specifications. These specifications will cater to various infrastructures such as backplanes, twin-axial copper cables, multimode optical fiber cables, and single-mode optical fiber cables, enabling Ethernet connections with a reach of up to 2 kilometers.
The IEEE P802.3dj Task Force is tasked with developing electrical and optical signaling technologies capable of achieving speeds of 200 Gb/s or higher per lane. Their mission extends to facilitating 800 Gb/s Ethernet operation and advancing towards the introduction of 1.6 Terabits per second (Tb/s) Ethernet operation. Their specifications will encompass electrical interfaces and physical layer details tailored for twin-axial copper cables and single-mode optical fiber cables, enabling Ethernet connections to span distances of up to 40 kilometers.
Key industry players’ approach to 1.6Tb/s
All the major system vendors, including CIENA, Infinera, Huawei and others have advanced plans for rolling out 1.6Tb/s.
To achieve a significant capacity increase using their WaveLogic 6 platform, CIENA aims to double the baud rate from 95Gbaud to approximately 200Gbaud. CIENA concedes that achieving such a high baud rate is a complex task, primarily because it necessitates high-bandwidth electro-optics, high-speed digital-to-analog and analog-to-digital converters (DACs and ADCs) with 100GHz of electrical bandwidth, and fitting all this processing power into the same physical space as current solutions. CIENA’s team overcame the first hurdle of high-bandwidth electro-optics through in-house development. They utilized a combination of electro-optic material systems to achieve the desired baud rate.
Infinera’s approach to achieving 1.6Tb/s is to use two wavelengths. Infinera’s plan on using their Infinite Capacity Engine (ICE6) to transmit two wavelengths, each at 800Gb/s. This remarkable achievement is made possible through a blend of sophisticated technologies, including a 7-nanometer CMOS process node digital ASIC/DSP, a tightly integrated indium phosphide (InP) photonic integrated circuit (PIC), high-performance analog electronics, and advanced packaging techniques.
Details of Huawei’s 1.6Tb/s platform technology is not readily available, but the company claims to have completed a field trial for 1.6Tb/s on a single wavelength as far back as 2021. In the context of a high-capacity DCI scenario, 96.5 kilometers of standard G.652 optical fibers were employed, along with standard EDFA optical amplifiers. During the test, 34 channels were transmitted over the operational network with a channel spacing of 150 gigahertz. Remarkably, the total capacity of the optical fiber surpassed 56 terabits per second, and the spectral efficiency exceeded 11 bits per second per hertz.
In conclusion, the relentless pursuit of achieving 1.6 terabits per second (Tb/s) data transmission rates has been driven by the ever-expanding demand for data across a multitude of applications. This race to 1.6Tb/s has seen the convergence of two pivotal technological advancements: coherent pluggable transceivers and advanced digital signal processing (DSP). Major industry players and standards organizations are actively engaged in the development of 1.6Tb/s solutions. Their strategies vary, from doubling baud rates to employing multiple wavelengths, but all share a common goal of pushing the boundaries of optical networking to accommodate the data-hungry world’s needs.
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Founder and Technical Director at FiberGuide, Lecturer, Scientist and Engineer. Passionate about optical networking and information and communication technologies. Connect with me on Linkedin – https://www.linkedin.com/in/jabulani-dhliwayo-1570b5b