Tag Archives: fiber cable

What are Fiber optic sensors

Fibers have many uses in remote sensing. In some applications, the sensor is itself an optical fiber. In other cases, fiber is used to connect a non-fiberoptic sensor to a measurement system. Depending on the application, fiber may be used because of its small size, or the fact that no electrical power is needed at the remote location, or because many sensors can be multiplexed along the length of a fiber by using different wavelengths of light for each sensor, or by sensing the time delay as light passes along the fiber through each sensor. Time delay can be determined using a device such as an optical time-domain reflectometer.

Optical fibers can be used as sensors to measure strain, temperature, pressure and other quantities by modifying a fiber so that the property to measure modulates the intensity, phase, polarization, wavelength, or transit time of light in the fiber. Sensors that vary the intensity of light are the simplest, since only a simple source and detector are required. A particularly useful feature of such fiber optic sensors is that they can, if required, provide distributed sensing over distances of up to one meter.

Extrinsic fiber optic sensors use an optical fiber cable, normally a multi-mode one, to transmit modulated light from either a non-fiber optical sensor—or an electronic sensor connected to an optical transmitter. A major benefit of extrinsic sensors is their ability to reach otherwise inaccessible places. An example is the measurement of temperature inside aircraft jet engines by using a fiber to transmit radiation into a radiation pyrometer outside the engine. Extrinsic sensors can be used in the same way to measure the internal temperature of electrical transformers, where the extreme electromagnetic fields present make other measurement techniques impossible. Extrinsic sensors measure vibration, rotation, displacement, velocity, acceleration, torque, and twisting. A solid state version of the gyroscope, using the interference of light, has been developed. The fiber optic gyroscope (FOG) has no moving parts, and exploits the Sagnac effect to detect mechanical rotation.

Common uses for fiber optic sensors includes advanced intrusion detection security systems. The light is transmitted along a fiber optic sensor cable placed on a fence, pipeline, or communication cabling, and the returned signal is monitored and analysed for disturbances. This return signal is digitally processed to detect disturbances and trip an alarm if an intrusion has occurred.

Related source: fiber optic patch cord, fiber optic attenuator, fiber optic loopback cable

About Optical fiber

An optical fiber (or optical fibre) is a flexible, transparent fiber made of glass (silica) or plastic, slightly thicker than a human hair. It can function as a waveguide, or “light pipe”, to transmit light between the two ends of the fiber. The field of applied science and engineering concerned with the design and application of optical fibers is known as fiber optics. Optical fibers are widely used in fiber-optic communications, which permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communication. Fibers are used instead of metal wires because signals travel along them with less loss and are also immune to electromagnetic interference. Fibers are also used for illumination, and are wrapped in bundles so that they may be used to carry images, thus allowing viewing in confined spaces. Specially designed fibers are used for a variety of other applications, including sensors and fiber lasers.

Optical fibers typically include a transparent core surrounded by a transparent cladding material with a lower index of refraction. Light is kept in the core by total internal reflection. This causes the fiber to act as a waveguide. Fibers that support many propagation paths or transverse modes are called multi-mode fibers (MMF), while those that only support a single mode are called single-mode fibers (SMF). Multi-mode fibers generally have a wider core diameter, and are used for short-distance communication links and for applications where high power must be transmitted. Single-mode fibers are used for most communication links longer than 1,050 meters (3,440 ft).

Joining lengths of optical fiber is more complex than joining electrical wire or cable. The ends of the fibers must be carefully cleaved, and then spliced together, either mechanically or by fusing them with heat. Special optical fiber connectors for removable connections are also available.

Network infrastructure among prime areas for IT investment

With many businesses facing pressure to make IT upgrades to support operational needs, budgets are rising and many companies are hiring more IT staff members. According to a recent CompTIA study, putting more resources into IT is a key trend for the next 12 months, during which network infrastructure will be a key area for spending.

According to the news source, the fundamental role of IT departments is beginning to change as more companies prioritize technology as a key business enabler. This is leading to more spending on IT infrastructure and heightened expectations for IT workers in general. Many companies are realizing that, with IT becoming more important, they need to invest more in strategic technologies.

Looking at IT investment strategies
Emerging technologies, like cloud computing, are among the key areas for IT investment, Tim Herbert, vice president of research for CompTIA, explained.

“”Emerging technologies such as cloud computing continue to see adoption gains as well,” said Herbert. “More than half of responding companies say they are either experimenting with or fully using cloud computing solutions.”

While cloud computing and similar solutions are gaining prominence, many organizations are focusing on more tried-and-true solutions. The study found that data storage, security, web services and network infrastructure are among the most prominent areas for investment during the next 12 months.

Drivers for network spending
Investing in new network equipment becomes a priority as companies begin to explore virtualization in the data center. Virtual architectures abstract the actual operating systems from the hardware, allowing multiple virtual machines to operate on a single server, even if the device only has one network port. As a result, data from 12 servers may be traveling through a single network port, leading to major bandwidth challenges. Advanced cabling systems and network virtualization can go a long way toward overcoming this issue.

Improving the core data center network is only part of the problem, as big data, cloud computing and a variety of other trends lead to more data not only being sent into and out of the data center, but between systems within facilities. As a result, organizations often need high-performance backhaul infrastructure. This often means fiber optic cables play an integral role in internal networks because emerging technologies are pushing data throughput requirements beyond what cable is ideally suited to handle. Strategic cabling investments can go a long way toward helping organizations support contemporary IT requirements.

Prysmian opens new fiber-optic cable plant in Romania

Cable maker Prysmian Group says it has a new fiber-optic cable production facility at its campus in Slatina, Romania. The new production capability will triple the factory’s fiber-optic cable capacity to 1.5 million km, with the potential to reach 3 million km.

Prysmian manufactures energy cable and copper cable as well as fiber cable at the 40-year-old Slatina factory, one of 24 production facilities the company operates worldwide. The site began producing fiber-optic cable in 2009. The plant comprises almost 100,000 m2 of space, 42,000 m2 of it covered, and employs more than 400 people.

“The investment in the new facility in Slatina is part of a major plan to further reinforce the Group’s competitiveness in this fast-changing market,” said Valerio Battista, CEO of the Prysmian Group. “Many developments are taking place in the current telecoms market. New players and services are appearing and evolution in broadband, double-play and triple-play services is dynamic. For this reason, as one of the major players in the telecom cable industry, Prysmian Group is continuously investing in this strategic sector in order to offer innovative technological solutions for the development of telecoms networks.”

Zayo boosts Indianapolis 500 small cell network with fiber-optic ring

Zayo Group reveals that it will deploy a dark fiber mobile backhaul infrastructure for a small cell wireless network at this year’s Indianapolis 500 in Indianapolis, IN. The fiber-optic network services provider already has installed a dark fiber ring for the track, which will improve wireless capacity and reliability during the race’s events. The fiber infrastructure will then remain in place to support mobile users.

The fiber optic cable will backhaul traffic from a distributed antenna system (DAS) deployed at the Indianapolis Motor Speedway. The backhaul network includes a 23-mile fiber ring connecting an unidentified national carrier’s multiple points of presence and the speedway. Zayo asserts it completed the dark fiber ring in fewer than 90 days.

Zayo says it manages more than 540 fiber route miles in the Indianapolis metro area and supports service to more than 300 buildings on-net.

How does a fiber optic cable work?

A fiber-optic cable is composed of many very thin strands of coated glass or plastic fibers that transmit light through the process of “cladding,” in which total internal reflection of light is achieved by using material that has a lower refractive index. Once light enters the fiber, the cladding layer inside it prevents light loss as the beam of light zigzags inside the glass core. Glass fibers can transmit messages or images by directing beams of light inside itself over very short or very long distances up to 13,000 miles (20,917 kilometers) without significant distortion. The pattern of light waves forms a code that carries a message. At the receiving end, the light beams are converted back into electric current and decoded. Uses include telecommunications medical fiber-optic viewers, such as endoscopes and fiberscopes, to see internal organs; fiber-optic message devices in aircraft and space vehicles; and fiber-optic connections in automotive lighting systems.

Fiber-optic cables have greater “bandwidth”: they can carry much more data than metal cable. Because fiber optics is based on light beams, the transmissions are more impervious to electrical noise and can also be carried greater distances before fading. The cables are thinner than metal wires. Fiber-optic cable delivers data in digital code instead of an analog signal, the delivery method of metal cables; computers are structured for digital, so there is a natural symbiosis. The main disadvantage is cost: fiber optics are much more expensive than traditional metal cable.

To understand how a fiber optic cable works, imagine an immensely long drinking straw or flexible plastic pipe. For example, imagine a pipe that is several miles long. Now imagine that the inside surface of the pipe has been coated with a perfect mirror. Now imagine that you are looking into one end of the pipe. Several miles away at the other end, a friend turns on a flashlight and shines it into the pipe. Because the interior of the pipe is a perfect mirror, the flashlight’s light will reflect off the sides of the pipe (even though the pipe may curve and twist) and you will see it at the other end. If your friend were to turn the flashlight on and off in a morse code fashion, your friend could communicate with you through the pipe. That is the essence of a fiber optic cable.

Related fiber optic cables – fiber optic patch cord, also called fiber optic patch cable, is a fiber optic cable terminated with fiber optic connectors on both ends. It has two major application areas: computer work station to outlet and fiber optic patch panels or optical cross connect distribution center. Fiber optic patch cables are for indoor applications only.

What is the difference between a single mode and multi mode fiber optic connector?

There are 2 major differences one color code. single mode will be white or yellow. multimode will be black or tan. 2nd the hole in the connector ferrel for the fiber. fiber is 125 microns. in a single mode connector the opening is 126 microns. multimode is 127/128.
Single Mode cable is a single strand (most applications use 2 fibers) of glass fiber with a diameter of 8.3 to 10 microns that has one mode of transmission. Single Mode Fiber with a relatively narrow diameter, through which only one mode will propagate typically 1310 or 1550nm. Carries higher bandwidth than multimode fiber, but requires a light source with a narrow spectral width. Synonyms mono-mode optical fiber, single-mode fiber, single-mode optical waveguide, uni-mode fiber.
Single Modem fiber is used in many applications where data is sent at multi-frequency (WDM Wave-Division-Multiplexing) so only one cable is needed – (single-mode on one single fiber)
Single-mode fiber gives you a higher transmission rate and up to 50 times more distance than multimode, but it also costs more. Single-mode fiber has a much smaller core than multimode. The small core and single light-wave virtually eliminate any distortion that could result from overlapping light pulses, providing the least signal attenuation and the highest transmission speeds of any fiber cable type.

Single-mode optical fiber is an optical fiber in which only the lowest order bound mode can propagate at the wavelength of interest typically 1300 to 1320nm.
Multi-Mode cable has a little bit bigger diameter, with a common diameters in the 50-to-100 micron range for the light carry component (in the US the most common size is 62.5um). Most applications in which Multi-mode fiber is used, 2 fibers are used (WDM is not normally used on multi-mode fiber). POF is a newer plastic-based cable which promises performance similar to glass cable on very short runs, but at a lower cost.
Multimode fiber gives you high bandwidth at high speeds (10 to 100MBS – Gigabit to 275m to 2km) over medium distances. Light waves are dispersed into numerous paths, or modes, as they travel through the cable’s core typically 850 or 1300nm. Typical multimode fiber core diameters are 50, 62.5, and 100 micrometers. However, in long cable runs (greater than 3000 feet [914.4 meters), multiple paths of light can cause signal distortion at the receiving end, resulting in an unclear and incomplete data transmission so designers now call for single mode fiber in new applications using Gigabit and beyond.

Multimode& Singlemode fiber are the five types of fiber in common use. Both fibers are 125 microns in outside diameter – a micron is one one-millionth of a meter & 125 microns is 0.005 inches- a bit larger than the typical human hair. Multimode fiber has light travelling in the core in lots of rays, called modes. It’s a bigger core (always 62.5 microns, but sometimes 50 microns) & is used with LED sources at wavelengths of 850 & 1300 nm for slower local area networks (LANs) & lasers at 850 & 1310 nm for networks jogging at gigabits per second or more. Singlemode fiber has a much smaller core, only about 9 microns, so that the light travels in one ray. It is used for telephony & CATV with laser sources at 1300 & 1550 nm. Plastic Optical Fiber (POF) is large core (about 1mm) fiber that can only be used for short, low speed networks.
Step index multimode was the first fiber design but is slow for most makes use of, due to the dispersion caused by the different path lengths of the various modes. Step index fiber is rare – only POF makes use of a step index design today.
Graded index multimode fiber makes use of variations in the composition of the glass in the core to compensate for the different path lengths of the modes. It offers hundreds of times more bandwidth than step index fiber – up to about 2 gigahertz.
Singlemode fiber shrinks the core down so small that the light can only travel in one ray. This increases the bandwidth to infinity – but it is practically limited to about 100,000 gigahertz – that is still a lot!

Multimode& Singlemode fiber are the five types of fiber in common use. Both fibers are 125 microns in outside diameter – a micron is one one-millionth of a meter & 125 microns is 0.005 inches- a bit larger than the typical human hair. Multimode fiber has light travelling in the core in lots of rays, called modes. It’s a bigger core (always 62.5 microns, but sometimes 50 microns) & is used with LED sources at wavelengths of 850 & 1300 nm for slower local area networks (LANs) & lasers at 850 & 1310 nm for networks jogging at gigabits per second or more. Singlemode fiber has a much smaller core, only about 9 microns, so that the light travels in one ray. It is used for telephony & CATV with laser sources at 1300 & 1550 nm. Plastic Optical Fiber (POF) is large core (about 1mm) fiber that can only be used for short, low speed networks.
Step index multimode was the first fiber design but is slow for most makes use of, due to the dispersion caused by the different path lengths of the various modes. Step index fiber is rare – only POF makes use of a step index design today.
Graded index multimode fiber makes use of variations in the composition of the glass in the core to compensate for the different path lengths of the modes. It offers hundreds of times more bandwidth than step index fiber – up to about 2 gigahertz.
Singlemode fiber shrinks the core down so small that the light can only travel in one ray. This increases the bandwidth to infinity – but it is practically limited to about 100,000 gigahertz – that is still a lot!

Source: fiber cable manufacturer