Fibre Optics

Before the advent of fibre optics, industrial communication systems heavily relied on traditional copper wire systems, such as twisted pair cables and coaxial cables. These systems, while adequate for the time, faced several limitations that significantly impacted their efficiency and reliability in data transmission. One of the primary limitations of copper wire systems was their restricted bandwidth. Copper, although perfectly adequate for voice signals, offers very limited bandwidth, especially when compared to fibre optics, which can provide standardized performance up to 10 Gbps and beyond. This limitation on bandwidth meant that the amount of data that could be transmitted over long distances without degradation was significantly constrained.

Furthermore, copper wires were highly susceptible to signal degradation over long distances due to electromagnetic interference (EMI) and radio frequency interference (RFI). This susceptibility resulted in a loss of data integrity and reliability, which was a major concern for industrial communication networks that required consistent and accurate data transmission. Distance limitations were another critical issue with copper wire systems. The signal strength in copper cables weakened as the distance increased, necessitating the use of signal repeaters or amplifiers to maintain signal quality. This not only added complexity to the communication network but also increased the overall cost. Additionally, copper cables had a short transmission distance, often less than 300 feet, which was unsuitable for long-distance data transmission. Copper wires were also vulnerable to environmental factors such as moisture, temperature fluctuations, and physical damage. These vulnerabilities could lead to potential interruptions in communication and system downtime, further emphasizing the need for a more robust solution.

The introduction of fibre optics in the 1980s addressed these limitations head-on. Fiber optic cables, capable of delivering up to 10Gbps and beyond, provided over 1,000 times as much bandwidth as copper and could travel more than 100 times further. Unlike copper wires, fibre optics were not susceptible to electromagnetic interference, allowing for clearer signal transmission over longer distances without degradation. Moreover, fibre optics supported longer cable segments than copper, enabling Gigabit speeds up to 1km on OM3+ multimode and up to 100 kilometres on single mode, thus overcoming the distance limitations associated with copper cables. In the 21st century, fibre optics became increasingly integrated with industrial automation and control systems. This integration facilitated real-time data transmission, remote monitoring, and control of industrial processes, making fibre optic networks essential components of modern industrial communication infrastructures.

The process begins with the encoding of digital data into light pulses, employing various modulation techniques such as amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM). These techniques adjust the properties of light—intensity, frequency, or phase—to represent the digital data accurately.

Once encoded, these light pulses are transmitted through optical fibres, which act as the conduit for data transmission. The core principle enabling the efficient travel of light within these fibres is total internal reflection. This phenomenon occurs at the interface between the core and the cladding of the fibre, ensuring that light signals are confined within the core and can propagate over long distances with minimal loss.

Upon reaching their destination, the light pulses encounter optical receivers, which play a crucial role in converting these optical signals back into electrical signals. This conversion is critical for the subsequent processing and analysis of the transmitted data. Photodiodes or photodetectors within these receivers are responsible for this optical-to-electrical conversion, generating electrical signals that correspond to the received light pulses.

The final stage in this communication process involves the decoding, processing, and analysis of the now-electrical signals. This step is essential for various industrial applications, including real-time monitoring and control, data analysis, and visualization.

In industrial communication, two primary types of optical fibres are utilized to meet the diverse needs of data transmission over varying distances: 

• Singlemode fibres (SMF) 

  Siglemode fibres are distinguished by its small core diameter, typically less than 10 micrometres, which allows it to support only a single mode of light propagation. This unique characteristic minimizes dispersion and attenuation, making SMF ideal for long-distance communication. It's capable of transmitting signals over much greater distances compared to MMF, thanks to its low dispersion and attenuation properties. Furthermore, SMF achieves large transmission capacities and can maintain the state of polarization over longer distances, which is crucial for various sensing applications and high-capacity circuits.

• Multimode fibres (MMF) 

  Multimode fibres are characterized by a larger core diameter, typically ranging from 50 to 62.5 micrometres, which supports the propagation of multiple light modes or rays simultaneously. This attribute allows MMF to transmit light signals across shorter distances, making it well-suited for use in industrial local area networks (LANs) and data centre applications where high bandwidth and fast data transmission over short distances are required.

The following elements are integral to the infrastructure of fibre optics, ensuring not only the reliability but also the efficiency of communication within industrial environments:

• Optical Transmitters

  This device is adept at converting electrical signals into optical signals, utilizing either a laser or a light-emitting diode (LED) to emit light pulses that mirror the input electrical signals.

• Optical Fibers

  Serving as the conduit through which light signals traverse, optical fibres are slender strands of glass or plastic. They are meticulously designed to guide light via total internal reflection, a principle that allows for the efficient ferrying of signals over considerable distances with minimal loss. 

• Connectors and Splices

  The integrity and continuity of fibre optic networks are maintained through connectors and splices. Connectors facilitate the joining of optical fibres to other components or to each other, while splices are employed for the permanent fusion of optical fibres, ensuring a seamless connection that minimizes signal degradation.

• Optical Receivers

  These devices typically comprise a photodiode or photodetector that captures incoming light pulses, transforming them into electrical signals for subsequent amplification and processing.

• Optical Amplifiers

  To counteract signal loss during transmission, optical amplifiers are strategically utilized to bolster the strength of optical signals sustaining signal quality across vast distances.

• Wavelength Division Multiplexing (WDM) Components

  Enables the simultaneous transmission of multiple wavelengths of light through a single fibre optic cable. This technology leverages multiplexers, demultiplexers, and optical filters to manage the various wavelengths of light, thereby facilitating multiple channels of data transmission concurrently.

Fiber optics technology has revolutionized industrial communication by addressing several limitations associated with traditional copper wire systems, as follow:

• High Bandwidth

  Allowing for the transmission of large amounts of data over long distances without degradation.

• Immunity to Electromagnetic Interference (EMI) and Radio Frequency Interference (RFI)

  This characteristic prevents signal degradation caused by nearby electrical equipment or power lines, maintaining high-quality data transmission.

• Longer Transmission Distances

  Fiber optic cables can transmit data over much longer distances without the need for signal repeaters or amplifiers, which is Ideal for applications spanning large facilities or remote locations due to less attenuation over distance compared to copper wires.

• Enhanced Security

  Fiber optic communication is inherently more secure than copper wire systems, as it is difficult to tap into or intercept optical signals without detection.

• Environmental Resistance

  Fiber optic cables exhibit higher resistance to environmental factors such as moisture, temperature extremes, and physical damage.

Fiber optics technology plays a pivotal role in revolutionizing communication, monitoring, and control within the oil and gas manufacturing and automation sector, as follow:

• Remote Monitoring and Control

  High-speed fibre optic links are crucial for transmitting sensor data, control signals, and video feeds from remote locations to central control centres. This capability allows operators to monitor operations and make informed decisions promptly, thereby optimizing performance and safety.

• Subsea Communication

  Subsea fibre optic networks facilitate the exchange of data between subsea production systems, control modules, and surface facilities. Such networks support critical tasks like well monitoring, production optimization, and equipment diagnostics in challenging offshore environments.

• Drilling and Exploration

  Technologies such as Distributed Temperature Sensing (DTS) and Distributed Acoustic Sensing (DAS) leverage fibre optic cables to gather comprehensive data along the length of the wellbore. This data provides invaluable insights into downhole conditions, significantly enhancing drilling efficiency and safety.

• Asset Integrity Management

  Fibre optic sensors and monitoring systems are utilized to detect variations in temperature, pressure, corrosion, and vibration, offering early warnings of potential equipment failures or safety hazards.

• Manufacturing 

  Fibre optic cables play a crucial role in transmitting high-resolution video feeds from machine vision systems to control centres. This application is essential for quality inspection, process monitoring, and defect detection in manufacturing processes, ensuring the highest standards of production are met.

• Supervisory Control and Data Acquisition (SCADA) systems in automation and control applications

  These systems enable remote monitoring and control of industrial processes, infrastructure, and utilities, such as power generation, water treatment, and transportation systems, showcasing the versatility and broad applicability of fibre optics in industrial settings.

As a leading company in the field of industrial communication, Hilscher offers a broad portfolio of technologies and solutions for networking industrial environments.

This includes a wide range of interface solutions for connecting sensors, actuators and controllers to industrial communication networks. The communication controllers of the netX family form the basis for this. The multi-protocol-capable SoCs can be flexibly integrated into automation components. A protocol change is achieved by simply reloading Hilscher's own netX firmware. Building on this, the company also offers embedded modules and PC cards in all form factors in order to realize the industrial communication interfaces with less integration effort.

Hilscher also offers a comprehensive managed industrial IoT range under the netFIELD brand. This ranges from edge gateways as an application-oriented computer platform with integrated container management and the Edge OS Runtime running on it to the central cloud portal, via which the docker containers are deployed to the edge devices, through to turnkey containers for communication applications.

Gateways and switches, devices for network diagnostics as well as masters and bridges for the wireless connection of IO-Link sensors round off the automation portfolio.