Telecommunications Archives - EFFECT Photonics

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February 14, 2024

Transceivers in Emergency Communications

Telecommunications are indispensable during emergencies and natural disasters for their pivotal role in coordinating emergency…

Telecommunications are indispensable during emergencies and natural disasters for their pivotal role in coordinating emergency responses, disseminating public safety information, and facilitating access to critical services. In times of crisis, efficient communication is essential for first responders, emergency services, and affected communities to collaborate seamlessly, allocate resources effectively, and ensure the safety of individuals.

Telecommunications also play a crucial role in family reunification, logistical support, and the gathering and disseminating of real-time information, contributing to well-informed decision-making and adaptive responses. Moreover, these communication channels provide emotional support, maintain social connections, and foster community resilience in adversity. As we navigate an unpredictable world fraught with natural disasters and unforeseen emergencies, the reliability of communication infrastructure becomes a lifeline for affected communities.

Optical transceivers for these disaster and emergency communications require specific characteristics to make them resistant to harsh environmental conditions and easier to install, deploy, and maintain. This article will dive into some ways that tunable transceivers can meet such requirements.

Self-Tuning Reduces Time to Service in Emergencies

Simplified provisioning and installation processes are essential to facilitate swift deployment, allowing responders to establish critical communication links without the burden of complex configurations. As time is often a critical factor during crises, transceivers should ideally adapt to the network environment to expedite the setup.

Typical tunable modules involve several tasks—manual tuning and verification of wavelength channel records—that can easily take an extra hour just for a single module installation. Self-tuning allows technicians to treat tunable modules the same way they do with grey transceivers. The network administrator could automate the configuration and provisioning of each transceiver unit from their central office, ship the units to each remote site, and the personnel in that site (who don’t need any technical experience!) just need to power up the unit. After turning them on, they could be further provisioned, managed, and monitored by experts anywhere in the world.

Figure 1: Short description and comparison of different approaches to wavelength tuning in optical transceivers, with the last one on the right being the self-tuning module.

Once plugged in, the transceiver will set the operational parameters as programmed and communicate with the central office for confirmation. These provisioning options make deployment much more accessible for network operators. This plug-and-play operation of self-tuning modules eliminates the additional time and complexity of deploying new nodes and DWDM links in optical access networks.

The Role of Remote Diagnostics

When disaster strikes, some areas may become isolated or pose safety risks, making on-site monitoring impractical. In these scenarios, remote diagnostics proves invaluable in maintaining communication links in hard-to-reach locations or those affected by adverse conditions. They enable real-time assessment of transceiver health, performance, and potential issues without direct physical intervention.

In EFFECT Photonics’ transceivers, the same channel that establishes parameters remotely during installation can also perform monitoring and diagnostics afterward. The headend module in the central office could remotely modify certain aspects of the tail-end module in the remote site, effectively enabling several remote management and diagnostics options. The figure below provides a visualization of such a scenario.

Figure 3: Visualization of remote diagnostics in an optical link. The headend module can check read tail-end module diagnostics such as wavelength channel number, temperature, transmitter, and receiver power. — Figure 2: Visualization of remote diagnostics in an optical link. The headend module can check read tail-end module diagnostics such as wavelength channel number, temperature, transmitter, and receiver power.

The central office can remotely measure metrics such as the transceiver temperature and power transmitted and received. These metrics can provide a quick and helpful health check of the link. The headend module can also remotely read alarms for low/high values of these metrics.

Industrially-Hardened Transceivers for Rough Environments

Typical transceivers reside in the controlled settings of data center machine rooms or network provider equipment rooms. These rooms have active temperature control, cooling systems, dust and particle filters, airlocks, and humidity control. In such a setting, pluggable transceivers must operate within the so-called commercial temperature range (c-temp) from 0 to 70ºC.

However, optical transceivers for emergency and disaster scenarios must survive the rough outdoor environments at the whims of Mother Nature. Transceivers should operate in the industrial temperature range (I-temp) for these outdoor settings from -40 to 85ºC. Higher altitude deployments provide additional challenges, too. Because the air gets thinner, networking equipment cooling mechanisms become less effective, and the device cannot withstand casing temperatures as high as they can at sea level.

Industrial hardening involves using robust materials, protective enclosures, and enhanced durability features, ensuring that the transceivers can endure the rigors of the outdoors. Making an I-temp transceiver means that every internal component must also be I-temp compliant. You can learn more about industrial hardening in the following article.

Takeaways

In times of crisis, the pivotal role of telecommunications in coordinating emergency responses and ensuring public safety cannot be overstated. The deployment of self-tuning transceivers reduces the time to service during emergencies by simplifying provisioning and installation processes. Their plug-and-play operation allows for swift deployment in remote locations, ensuring that critical communication links are established efficiently, even by personnel without technical expertise.

Remote diagnostics capabilities help maintain communication links in hard-to-reach or hazardous locations, enabling real-time assessment without physical intervention. In these cases, industrial hardening of transceivers also emerges as a critical necessity, ensuring their resilience in rough outdoor environments subjected to the unpredictable forces of nature. By meeting these requirements, optical transceivers become resilient components of emergency communication systems, contributing significantly to the reliability and effectiveness of communication networks when they are needed most.

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Tags: Adaptive Responses, Communication Infrastructure, Coordinating Emergency Responses, Crisis Communication, Critical Services, Emergency Communications, Family Reunification, First Responders, Industrial Hardening, Logistical Support, Natural Disasters, Optical Access Networks., Public Safety Information, Real-time Information, remote diagnostics, self-tuning, Swift Deployment, Telecommunications, Transceivers, tunable transceivers

Insights

November 15, 2023

The Highways of Light: How Optical Fiber Works

Optical fibers revolutionized how we transmit data, enabling faster long-distance connections. These slender strands of…

Optical fibers revolutionized how we transmit data, enabling faster long-distance connections. These slender strands of glass or plastic carry light pulses and serve as the backbone of modern telecommunication networks. Optical fibers have found applications beyond communications, including imaging, sensing, and medicine, further showcasing their versatility and impact in various fields.

Early optical fibers suffered significant losses during transmission, limiting their practicality for long-haul communication. In 1966, Charles Kao and George Hockham proposed that impurities in the glass were responsible for these losses, and they suggested that high-purity silica glass could achieve a much more reasonable attenuation of 20 dB per kilometer for telecommunications. This breakthrough, for which Kao received the Nobel Prize in Physics in 2009, kickstarted an era of explosive progress and growth for optical fiber.

In 1970, Corning scientists Robert Maurer, Donald Keck, and Peter Schultz successfully fabricated a glass fiber with an attenuation of 16 dB per kilometer, exceeding the performance benchmark set by Kao and Hockham. Two years later, Corning pushed the envelope further and achieved a loss of 4 dB/km, an order of magnitude improvement over their first effort. By 1979, Nippon Telegraph and Telephone (NTT) had reached a loss of 0.2 dB/km, meaning that only 5% of the light signal was lost over one kilometer. Optical fibers were ready for the world stage and deployed worldwide throughout the 1980s. The first transatlantic optical fiber link, spanning 6000 km, was established in 1988.

In this article, we will delve into the fascinating world of optical fibers, exploring how they work and what role optical transceivers play in fiber communications.

The Principle of Total Internal Reflection

Light bends when it passes from one material to another, such as from air to water. This bending occurs due to the change in the speed of light when it encounters a different material, causing the light rays to change direction. How much light changes direction depends on the angle at which it enters the new material and the factor by which the material slows down light. The latter factor is known as the refractive index of the material.

Figure 1 GREEN PENCIL IN GLASS OF WATER 1024 — Figure 1: Light refraction from a green-colored pencil inside a glass of water.

When light travels from a material of a higher refractive index to one of a lower index at a specific critical angle, the light will be entirely reflected into the high-index material. This phenomenon is called total internal reflection and is the fundamental principle behind the operation of optical fibers.

Optical Fibers and Total Internal Reflection

Optical fibers consist of a high-refractive-index core surrounded by a low-refractive-index cladding layer. Light entering the fiber core through one end at the correct critical angle will bounce back whenever it reaches the boundary between the core and the cladding. This behavior effectively traps light inside the core, allowing the light pulses to propagate through the fiber with minimal loss over long distances.

Figure 2: Diagram of light trapped inside an optical fiber by total internal reflection.

Optical fibers can achieve single-mode or multi-mode operation by carefully engineering the refractive indices of the core and cladding. Single-mode fibers have a small core diameter to transmit only a single optical mode or path. In contrast, multi-mode fibers have a larger core diameter, enabling the propagation of multiple modes simultaneously.

Figure 3: Comparing light propagation in multimode fiber and single-mode fiber. While the claddings are the same size, the single-mode fiber core is much smaller than the multimode one.

The quality of the light signal degrades when traveling through an optical fiber by a process called dispersion. The same phenomenon happens when a prism splits white light into several colors. The single-mode fiber design minimizes dispersion, making single-mode fibers ideal for long-distance communication. Since they are more susceptible to dispersion, multi-mode fibers are well-suited for short-distance applications such as local area networks (LANs).

The Role of Optical Transceivers in Fiber

Optical transceivers play a crucial role in fiber communications by converting electrical signals into optical signals for fiber transmission and vice versa when the optical signal is received. They act as the interface between fiber optical networks and electronic computing devices such as computers, routers, and switches.

As the name implies, an optical transceiver contains both a transmitter and a receiver within a single module. The transmitter has a laser or LED that generates light pulses representing the electronic data signal. On the receiving end, the receiver detects the optical signals and converts them back into electrical signals, which electronic devices can further process.

Figure 4: How transceivers convert electrical data signals into light pulses and vice-versa.

There are many different approaches to encode electrical data into light pulses. Two key approaches are intensity modulation/direct detection (IM-DD) and coherent transmission. IM-DD transmission only uses the amplitude of the light signal to encode data, while coherent transmission manipulates three different light properties to encode data: amplitude, phase, and polarization. These additional degrees of modulation allow for faster optical signals without compromising the transmission distance.

Direct Detection or Coherent? EFFECT Photonics explains

Takeaways

Optical fibers have transformed telecommunications in the last 50 years, enabling the rapid and efficient transmission of data over vast distances. By exploiting the principles of total internal reflection, these slender strands of glass or plastic carry pulses of light with minimal loss, ensuring high-speed communication worldwide. Optical transceivers act as the vital link between optical fiber and electronic networking devices, facilitating the conversion of electrical signals to optical signals and vice versa. Optical fibers and transceivers are at the forefront of our interconnected world, serving as the highways of light the digital age drives on.

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Tags: amplifiers, cladding, coherent, conversion, core, Corning, detector, Direct Detect, dispersion, EFFECT Photonics, electrical, fiber, laser, Networks, Nobel Prize, noise, NTT, optical, refraction, refractive index, Telecommunications, total internal reflections, total internal relection, Transceiver

Insights

March 22, 2023

Transceivers in the Age of AI

Artificial intelligence (AI) will have a significant role in making optical networks more scalable, affordable,…

Artificial intelligence (AI) will have a significant role in making optical networks more scalable, affordable, and sustainable. It can gather information from devices across the optical network to identify patterns and make decisions independently without human input. By synergizing with other technologies, such as network function virtualization (NFV), AI can become a centralized management and orchestration network layer. Such a setup can fully automate network provisioning, diagnostics, and management, as shown in the diagram below.

Figure 1: Example of a carrier network with different applications (mobile, home, office) automated via NFV control and AI management.

However, artificial intelligence and machine learning algorithms are data-hungry. To work optimally, they need information from all network layers and ever-faster data centers to process it quickly. Pluggable optical transceivers thus need to become smarter, relaying more information back to the AI central unit, and faster, enabling increased AI processing.

Faster Transceivers for the Age of AI

Optical transceivers are crucial in developing better AI systems by facilitating the rapid, reliable data transmission these systems need to do their jobs. High-speed, high-bandwidth connections are essential to interconnect data centers and supercomputers that host AI systems and allow them to analyze a massive volume of data.

In addition, optical transceivers are essential for facilitating the development of artificial intelligence-based edge computing, which entails relocating compute resources to the network’s periphery. This is essential for facilitating the quick processing of data from Internet-of-Things (IoT) devices like sensors and cameras, which helps minimize latency and increase reaction times.

400 Gbps links are becoming the standard across data center interconnects, but providers are already considering the next steps. LightCounting forecasts significant growth in the shipments of dense-wavelength division multiplexing (DWDM) ports with data rates of 600G, 800G, and beyond in the next five years. We discuss these solutions in greater detail in our article about the roadmap to 800G and beyond.

Figure 2: Shipments of high-speed DWDM ports by data rate (historical data and forecast). Source: LightCounting Optical Communications Market Forecast, April 2022.

Coherent Modules Need to Provide More Telemetry Data

Mobile networks now and in the future will consist of a massive number of devices, software applications, and technologies. Self-managed, zero-touch automated networks will be required to handle all these new devices and use cases. Realizing this full network automation requires two vital components.

Artificial intelligence and machine learning algorithms for comprehensive network automation: For instance, AI in network management can drastically cut the energy usage of future telecom networks.
Sensor and control data flow across all network model layers, including the physical layer: As networks grow in size and complexity, the management and orchestration (MANO) software needs more degrees of freedom and dials to turn.

These goals require smart optical equipment and components that provide comprehensive telemetry data about their status and the fiber they are connected to. The AI-controlled centralized management and orchestration layer can then use this data for remote management and diagnostics. We discuss this topic further in our previous article on remote provisioning, diagnostics, and management.

For example, a smart optical transceiver that fits this centralized AI-management model should relay data to the AI controller about fiber conditions. Such monitoring is not just limited to finding major faults or cuts in the fiber but also smaller degradations or delays in the fiber that stem from age, increased stress in the link due to increased traffic, and nonlinear optical effects. A transceiver that could relay all this data allows the AI controller to make better decisions about how to route traffic through the network.

A Smart Transceiver to Rule All Network Links

After relaying data to the AI management system, a smart pluggable transceiver must also switch parameters to adapt to different use cases and instructions given by the controller.

Let’s look at an example of forward error correction (FEC). FEC makes the coherent link much more tolerant to noise than a direct detect system and enables much longer reach and higher capacity. In other words, FEC algorithms allow the DSP to enhance the link performance without changing the hardware. This enhancement is analogous to imaging cameras: image processing algorithms allow the lenses inside your phone camera to produce a higher-quality image.

Figure 1 Simplified diagram of a network link with Forward Error Correction (FEC). — Figure 3: Simplified diagram of a network link with forward error correction (FEC). The FEC encoder adds redundant bits (overhead) to the transmitted data stream. The receiver can use this overhead to check for errors without asking the transmitter to resend the data.

A smart transceiver and DSP could switch among different FEC algorithms to adapt to network performance and use cases. Let’s look at the case of upgrading a long metro link of 650km running at 100 Gbps with open FEC. The operator needs to increase that link capacity to 400 Gbps, but open FEC could struggle to provide the necessary link performance. However, if the transceiver can be remotely reconfigured to use a proprietary FEC standard, the transceiver will be able to handle this upgraded link.

Reconfigurable transceivers can also be beneficial to auto-configure links to deal with specific network conditions, especially in brownfield links. Let’s return to the fiber monitoring subject we discussed in the previous section. A transceiver can change its modulation scheme or lower the power of its semiconductor optical amplifier (SOA) if telemetry data indicates a good quality fiber. Conversely, if the fiber quality is poor, the transceiver can transmit with a more limited modulation scheme or higher power to reduce bit errors. If the smart pluggable detects that the fiber length is relatively short, the laser transmitter power or the DSP power consumption could be scaled down to save energy.

Takeaways

Optical networks will need artificial intelligence and machine learning to scale more efficiently and affordably to handle the increased traffic and connected devices. Conversely, AI systems will also need faster pluggables than before to acquire data and make decisions more quickly. Pluggables that fit this new AI era must be fast, smart, and adapt to multiple use cases and conditions. They will need to scale up to speeds beyond 400G and relay monitoring data back to the AI management layer in the central office. The AI management layer can then program transceiver interfaces from this telemetry data to change parameters and optimize the network.

Tags: 800G, 800G and beyond, adaptation, affordable, AI, artificial intelligence, automation, CloudComputing, data, DataCenter, EFFECT Photonics, FEC, fiber quality, innovation, integration, laser arrays, machine learning, network conditions, network optimization, Networking, optical transceivers, photonic integration, Photonics, physical layer, programmable interface, scalable, sensor data flow, technology, Telecommunications, telemetry data, terabyte, upgrade, virtualization

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