Monthly Archives: August 2013

The Difference Between Single Mode and Multi Mode Fiber Optics

You’ve probably heard the terms “single mode” and “multi mode” fiber optic cables. But what’s the difference between single mode and multi mode fiber optics? Well, it’s pretty simple – but you have to go INSIDE the cable for the answer.

Basically, the main difference with each type of fiber optic cable is the interior size.

Single mode fibers consist of a tiny glass core that typically has a diameter between 8.3 and 10 microns (9 microns is a popular size). The single glass strand carrier higher bandwidth than multi mode fiber optic. However, the single mode fiber optic uses one light source in a tight spectral width. The result? Single mode fiber optic is your best choice for transferring high speed data over long distances. Their unique properties make single mode less susceptible to attenuation than multi mode fiber optics.
Multi mode fibers contain much larger cores than single mode. Their cores are anywhere from 5 to 7 times larger than single mode cores. With a diameter ranging between 50 to 62.5 microns, multi mode fiber optics can accommodate a higher data volume than single mode. But with the greater capacity comes a setback – multi mode fiber optics have higher attenuation levels, so they’re typically used over shorter distances.
When choosing fiber optic cable for your network, the key considerations should be attenuation and distance. If you need to transmit less data over longer distances, use single mode fiber optic cables. For a greater data capacity over shorter distances, go with multi mode fiber optic cables. Multi mode is often used for LANs and other small networks.

Refresh hollow photonic bandgap fiber data transmission record

British scientists have claimed that the use of model-based reuse 37 hollow core photonic bandgap fiber (HC-PBGF), created a 73.7Tbit / s transfer rate of the new record. Optoelectronics Research Centre, University of Southampton, Senior Fellow Yongmin Jung and his colleagues produced the world’s first low-loss broadband 37 root core HC-PBGF, there is no internal surface mode and low crosstalk.

The 37-core hollow fiber, hollow fiber core at 19 on the basis of further weakening of these fibers inside the main loss mechanism – surface scattering. The team produced the diameter of 37μm fiber cladding spacing of 4.4μm, the relative aperture is 0.97, the band gap will be about 300nm. This fiber at 1550nm wavelength with a minimum basic pattern 3.3dB/km loss.

HC-PBGF lattice structure is rather special – larger air holes around the core of honeycomb covered. Since the signal propagation in the air, the data transfer rate is much higher than conventional fibers. Further, a transmission method is transmitted by the photonic bandgap effect, rather than the conventional fibers in the total internal reflection. Although, compared to the solid fiber, HC-PBGF has a lower nonlinearity, low loss and low latency access to more potential, but there are still some problems to be studied, especially in relation to the receiver using MIMO technology deal model of the problem.

Source: fiber optic cables, fiber optic transceiver and converter

Corning introduced advanced optical components for data center

Pretium EDGE AO solutions to similar parallel optical solution 33% higher density to help implement parallel optical technology to 40 g / 100 g of migration

Corning corporation recently announced a set of oriented Pretium EDGE solutions platform of optical components products – Pretium EDGE AO (advanced optical) solution. These components can help data center to its economic and efficient way cable infrastructure easily migrated to the next generation of more advanced applications, including parallel optical technology and integration of network monitoring.

Parallel optical Pretium EDGE AO solution is composed of switching module and fiber optic jumper, it in the network to 40 g migration can fully use 12 core optical fiber backbone, 40 g using 8 core optical fiber backbone (in each direction has four optical fibers with 10 g speed transmission). If there is no this kind of transfer, the existing fiber optic backbone running 40 g parallel optical fiber data centers use only about 66% of the fiber has been installed.

Due to the application of the resistance to bending, corning ClearCurve multimode fiber Pretium EDGE AO solutions to achieve the industry’s highest density of parallel optical frame; Its density is equivalent to the current Pretium EDGE10G solution, the density of at least 33% higher compared with other parallel optical solutions. Due to the port density with 10 g solutions now, the end user in a migration to a higher data rate without increasing the system hardware. Will be moved to 40 g or higher rate of customer is expected to achieve a good return on investment, because they can after migration full use of its existing fiber optic backbone and hardware.

Once submitted review 4 x25g IEEE 802.3 bm Ethernet standard approved (in each direction has four optical fibers with 25 g speed transport), due to the switching module and fiber optic jumper can continue to used to transport 100 g Pretium EDGE AO solution will be 100 g additional return on investment for the user.

As part of the Pretium EDGE AO solutions, corning also launched the industry’s first integrated port divider module, used for Ethernet 40 gbase – SR4 multimode fiber parallel optical circuit implementation of network monitoring. This passive tap device can be directly integrated into the Pretium EDGE solutions for infrastructure, and it all – the MTP adapter can support 40G seamless migration of electronic equipment. Divider with corning other integration of port module, this integration method of corning allowed under the premise of not interfere with the real-time network connection increase or dismantle the monitored port, and to achieve “zero U” footprint, improve the utilization rate of frame.

Source: fiber optic components

AFL unveils NOYES FOCIS PRO for fiber-optic connector inspection

AFL has unveiled the NOYES FOCIS PRO family of automatic fiber inspection systems. The fiber optic connector inspection systems automate the process of analyzing and documenting fiber connector cleanliness and integrity.

Designed for field inspection tasks, FOCIS PRO offers optical resolution and detection specifications that exceed current international standards, AFL asserts. The units’ software-based applications are upgradeable, which prolongs the FOCIS PRO units’ useful lifespans.

A FOCIS PRO System consists of the DFD1 Touchscreen Tablet, the DFS1 Digital FiberScope, and the new SimpleView PRO software. The units can help technicians center a fiber image; identify critical core, cladding, adhesive, and contact zones, and detect and record the types of defects found. Technicians can analyze a typical fiber in under five seconds, AFL asserts. Meanwhile, the unit’s Zoom/Pan feature and large display enable users to identify the smallest particles, scratches, and imperfections, the company adds.

The systems benefit from a patent-pending paired image feature designed to enable users to make immediate fiber cleanliness comparisons. Users can capture and save up to 1,000 fiber images, review images on-site, and share images via USB memory sticks or SD flash cards.

All of AFL’s FOCIS units can be upgraded to the functionality of FOCIS PRO.

“As network vendors pursue higher data rates associated with the substantial growth in data traffic, the demand for exceptional performance of network systems is becoming more and more crucial,” explained Bill Thompson, marketing director for AFL’s fiber optic test equipment division. “Simply stated, it is imperative that fibers are clean and free from defects. AFL’s FOCIS PRO system delivers a solution that supports these demanding requirements.”

The History of Fiber Optics

Fiber optics, though used extensively in the modern world, is a fairly simple, and relatively old, technology. Guiding of light by refraction, the principle that makes fiber optics possible, was first demonstrated by Daniel Colladon and Jacques Babinet in Paris in the early 1840s. John Tyndall included a demonstration of it in his public lectures in London, 12 years later. Tyndall also wrote about the property of total internal reflection in an introductory book about the nature of light in 1870: “When the light passes from air into water, the refracted ray is bent towards the perpendicular… When the ray passes from water to air it is bent from the perpendicular… If the angle which the ray in water encloses with the perpendicular to the surface be greater than 48 degrees, the ray will not quit the water at all: it will be totally reflected at the surface…. The angle which marks the limit where total reflection begins is called the limiting angle of the medium. For water this angle is 48°27′, for flint glass it is 38°41′, while for diamond it is 23°42′.” Undigested human hairs have also been shown to act as an optical fiber.

Practical applications, such as close internal illumination during dentistry, appeared early in the twentieth century. Image transmission through tubes was demonstrated independently by the radio experimenter Clarence Hansell and the television pioneer John Logie Baird in the 1920s. The principle was first used for internal medical examinations by Heinrich Lamm in the following decade. Modern optical fibers, where the glass fiber is coated with a transparent cladding to offer a more suitable refractive index, appeared later in the decade. Development then focused on fiber bundles for image transmission. Harold Hopkins and Narinder Singh Kapany at Imperial College in London achieved low-loss light transmission through a 75 cm long bundle which combined several thousand fibers. Their article titled “A flexible fiberscope, using static scanning” was published in the journal Nature in 1954. The first fiber optic semi-flexible gastroscope was patented by Basil Hirschowitz, C. Wilbur Peters, and Lawrence E. Curtiss, researchers at the University of Michigan, in 1956. In the process of developing the gastro scope, Curtiss produced the first glass-clad fibers; previous optical fibers had relied on air or impractical oils and waxes as the low-index cladding material.

A variety of other image transmission applications soon followed.

In 1880 Alexander Graham Bell and Sumner Tainter invented the ‘Photo phone’ at the Volta Laboratory in Washington, D.C., to transmit voice signals over antical beam. It was an advanced form of telecommunications, but subject to atmospheric interferences and impractical until the secure transport of light that would be offered by fiber-optical systems. In the late 19th and early 20th centuries, light was guided through bent glass rods to illuminate body cavities. Jun-ichi Nishizawa, a Japanese scientist at Tohoku University, also proposed the use of optical fibers for communications in 1963, as stated in his book published in 2004 in India. Nishizawa invented other technologies that contributed to the development of optical fiber communications, such as the graded-index optical fiber as a channel for transmitting light from semiconductor lasers. The first working fiber-optical data transmission system was demonstrated by German physicist Manfred Börner at Telefunken Research Labs in Ulm in 1965, which was followed by the first patent application for this technology in 1966. Charles K. Kao and George A. Hockham of the British company Standard Telephones and Cables (STC) were the first to promote the idea that the attenuation in optical fibers could be reduced below 20 decibels per kilometer (dB/km), making fibers a practical communication medium. They proposed that the attenuation in fibers available at the time was caused by impurities that could be removed, rather than by fundamental physical effects such as scattering. They correctly and systematically theorized the light-loss properties for optical fiber, and pointed out the right material to use for such fibers — silica glass with high purity. This discovery earned Kao the Nobel Prize in Physics in 2009.

NASA used fiber optics in the television cameras sent to the moon. At the time, the use in the cameras was classified confidential, and only those with the right security clearance or those accompanied by someone with the right security clearance were permitted to handle the cameras.

The crucial attenuation limit of 20 dB/km was first achieved in 1970, by researchers Robert D. Maurer, Donald Keck, Peter C. Schultz, and Frank Zima working for American glass maker Corning Glass Works, now Corning Incorporated. They demonstrated a fiber with 17 dB/km attenuation by doping silica glass with titanium. A few years later they produced a fiber with only 4 dB/km attenuation using germanium dioxide as the core dopant. Such low attenuation ushered in optical fiber telecommunication. In 1981, General Electric produced fused quartz ingots that could be drawn into fiber optic strands 25 miles (40 km) long.
Attenuation in modern optical cables is far less than in electrical copper cables, leading to long-haul fiber connections with repeater distances of 70–150 kilometers (43–93 mi). The erbium-doped fiber amplifier, which reduced the cost of long-distance fiber systems by reducing or eliminating optical-electrical-optical repeaters, was co-developed by teams led by David N. Payne of the University of Southampton and Emmanuel Desurvire at Bell Labs in 1986. Robust modern optical fiber uses glass for both core and sheath, and is therefore less prone to aging. It was invented by Gerhard Bern see of Schott Glass in Germany in 1973.

The emerging field of photonic crystals led to the development in 1991 of photonic-crystal fiber, which guides light by diffraction from a periodic structure, rather than by total internal reflection. The first photonic crystal fibers became commercially available in 2000. Photonic crystal fibers can carry higher power than conventional fibers and their wavelength-dependent properties can be manipulated to improve performance.

Source: fiber optic cable manufacturer