Tag Archives: communication

Introduction Of Specialty Fibers For Optical Communication Systems

Optical fiber communications have changed our lives over the last 40 years. There is no doubt that low-loss optical transmission fibers have been critical to the enormous success of optical communications technology. It is less well known however, that fiber-based components have also played a critical role in this success.

Initially, fiber optic transmission systems were point to point systems, with lengths significantly less than 100 km. Then in the 1980s, rapid progress was made on the research and understanding of optical components including fiber components. Many of these fiber components found commercial applications in optical sensor technology such as in fiber gyroscopes and other optical sensor devices. Simple components such as power splitters, polarization controllers, multiplexing components, interferometric devices, and other optical components proved to be very useful. A significant number of these components were fabricated from polarization maintaining fibers (PMFs). You can buy the PM fiber patch cables from Fiberstore.

Although not a large market, optical fiber sensor applications spurred research into the fabrication of new components such as polarization maintaining components, other components such as power splitters were fabricated from standard multimode (MM) or single-mode telecommunication fiber. In the telecommunication sector, the so-called passive optical network was proposed for the already envisioned fiber-to-the-home (FTTH) network. This network relied heavily on the use of passive optical splitters. These splitters were fabricated from standard single-mode fibers (SMFs). Click here to get the price single mode cable fiber optic. Although FTTH, at a large scale, did not occur until decades later, research into the use of components for telecommunications applications continued.

The commercial introduction of the fiber optical amplifier in the early 1990s revolutionized optical fiber transmissions. With amplification, optical signals could travel hundreds of kilometers without regeneration. This had major technical as well as commercial implications. Rapidly, new fiber optic components were introduced to enable better amplifiers and to enhance these transmission systems. Special fibers were required for the amplifier, for example, erbium-doped fibers. The design of high-performance amplifier fibers required special considerations of mode field diameter, overlap of the optical field with the fiber active core, core composition, and use of novel dopants. Designs radically different from those of conventional transmission fiber have evolved to optimize amplifier performance for specific applications. The introduction of wavelength division multiplexing (WDM) technology put even greater demands on fiber design and composition to achieve wider bandwidth and flat gain. Efforts to extend the bandwidth of erbiumdoped fibers and develop amplifiers at other wavelength such as 1300nm have spurred development of other dopants. Codoping with ytterbium (Yb) allows pumping from 900 to 1090nm using solid-state lasers or Nd and Yb fiber lasers. Of recent interest is the ability to pump Er/Yb fibers in a double-clad geometry with high power sources at 920 or 975 nm. Double-clad fibers are also being used to produce fiber lasers using Yb and Nd.

Besides the amplication fiber, the EDFA (Erbium-Doped Fiber Amplifier) requires a number of optical components for its operation. These include wavelength multiplexing and polarization multiplexing devices for the pump and signal wavelengths. Filters for gain flattening, power attenuators, and taps for power monitoring among other optical components are required for module performance. Also, because the amplifier-enable transmission distance of hundreds of kilometers without regeneration, other propagation propeties became important. These properties include chromatic dispersion, polarization dispersion, and nonlinearities such as four-wave mixing (FWM), self-and cross-phase modulation, and Raman and Brillouin scattering. Dispersion compensating fibers were introduced in order to deal with wavelength dispersion. Broadband coupling losses between the transmission and the compensating fibers was an issue. Specially designed mode conversion or bridge fibers enable low-loss splicing among these thre fibers, making low insertion loss dispersion compensators possible. Fiber components as well as microoptic or in some instance planar optical components can be fabricated to provide for these applications. Generally speaking, but not always, fiber components enable the lowest insertion loss per device. A number of these fiber devices can be fabricated using standard SMF, but often special fibers are required.

Specialty fibers are designed by changing fiber glass composition, refractive index profile, or coating to achieve certain unique properties and functionalities. In addition to applications in optical communications, specialty fibers find a wide range of applications in other fields, such as industrial sensors, biomedical power delivery and imaging systems, military fiber gyroscope, high-power lasers, to name just a few. There are so many linds of specialty fibers for different applications. Some of the common specialty fibers include the following:

Active Fibers: These fibers are doped with a rare earth element such as Er, Nd, Yb or another active element, The fibers are used for optical amplifiers and lasers. Erblium doped fiber amplifiers are a goog example of fiber components using an active fiber. Semiconductor and nanoparticle doped fibers are becoming an interesting research topic.
Polarization Control Fibers: These fibers have high birefringence that can maintain the polarization state for a long length of fiber. The high birefringence is introduced either by asymmetric stresses such as in Panda, and bowtie design. If both polarization modes are available in the fiber, the fiber is called PMF. If only one polarization mode propagates in the fiber while the other polarization mode is cutoff, the fiber is called single polarization fiber.
Dispersion Compensation Fibers: Fibers have opposite chromatic dispersion to that of transmission fibers such as standard SMFs and nonzero dispersion shifted fibers (NZDSFs). The fibers are used to make dispersion compensation modules for mitigating dispersion effects in a fiber transmission system.
Highly Nonlinear Optical Fibers: Fibers have high nonlinear coefficient for use in optical signal processing and sensing using optical nonlinear effects such as the optical Kerr effect, Brillouin scattering, and Raman scattering.
Coupling Fibers or Bridge Fibers: Fibers have mode field diameter between the standard SMF and a specialty fiber. The fiber serves as an intermendiate coupling element to reduce the high coupling loss between the standard SMF and the specialty fiber.
Photo-Sensitive Fibers: Fibers whose refractive index is sensitive to ultraviolet (UV) light. This type of fiber is used to produce fiber gratings by UV light exposure.
High Numerical Aperture (NA) Fibers: Fibers with NA higher than 0.3. These fibers are used for power delivery and for short distance communication applications.
Special SMFs: This category includes standard SMF with reduced cladding for improved bending performance, and specially designed SMF for short wavelength applications.
Specially Coated Fibers: Fibers with special coating such as hermitic coating for preventing hydrogen and water penetration, metal coating for high temperature applications.
Mid-Infrared Fibers: Non-silica glass-based fibers for applications between 2 and 10 micron
Photonic Crystal Fibers (PCFs): Fibers with periodic structure to achieve fiber properties that are not available with conventional fiber structures.

More fiber optics, such as patch cord, patch panel, fiber adapters, fiber connectors, please visit our websites http://www.jfiberoptic.com, http://www.jfcable.com and http://www.jfopt.es

Fbt Coupler Fiber Optic Patch Cables And Dwdm Sfp Transceiver

Fiber optic splitter is used to split the fiber optic light into several parts at a certain ratio. We use fiber optic splitter to distribute or combine optical signals in many applications, such as FTTH solution, etc. Fiber optic splitters are important passive components used in FTTX networks. Fiber optic splitters can be terminated with different kinds of connectors, the main package could be box type or stainless tube type, one is usually used with 2mm or 3mm outer diameter cable, the other is usually used with 0.9mm outer diameter cables.

Two kinds of fiber splitters are popular used, one is the traditional fused type fiber optic splitter (FBT coupler), which features competitive prices; the other is PLC fiber optic splitter, which is compact size and suit for density applications. Both of them have its advantages to suit for different requirement. FBT Couplers are designed for power splitting and tapping telecommunication equipment, CATV networks, and test equipment. These components are available individually or integrated into modules for fiber protection switching, MUX/DMUX, optical channel monitoring, and add/drop multiplexing applications.

Major differences between PLC splitters and FBT Coupler

1. Technology behind FBT Coupler and PLC splitter.
FBT coupler: Fused Biconical Taper, this is traditional technology to weld several fiber together from side of the fiber.
PLC splitter: Planar Lightwave Circuit is a micro-optical components product, the use of lithography, the semiconductor substrate in the medium or the formation of optical waveguide, to achieve
branch distribution function.

2. Disadvantages and advantages between FBT and PLC.
PLC splitter FBT coupler
SpliSplit Ratio (Max) 1*64 splits 1*4 splits
EveEveness Can split light evenly Eveness is not very precise
SizeSizeSize Compact size Big size for multi splits

Fiber Patch Cable also known as fiber jumper or fiber patch cord, which is a fiber optic cable terminated with fiber optic connectors on both ends. There are two major application areas of Fiber
Patch Cable: 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. Single-mode fiber
Patch cable is primarily used for applications involving extensive distances. Multimode fiber optic patch cord, however, is the cable of choice for most common local fiber systems as the devices for multimode are far cheaper.

Jfiberoptic Dense Wavelength Division Multiplexing (DWDM) Small Form-Factor Pluggable (SFP) is available in all 100 GHz C-band wavelengths on the DWDM ITU grid. They are designed to Multi-Source Agreement (MSA) standards to ensure broad network equipment compatibility. As multirate interfaces they support any protocol from 100 Mbps to 4.25 Gbps. DWDM SFP transceivers provide the high speeds and physical compactness that today’s networks require while delivering the deployment flexibility and inventory control that network administrators demand. The 1.25G DWDM SFP transceivers are small form factor pluggable modules for bi-directional serial optical data communications such as 4x/2x/1x Fibre Channel, SDH/SONET, Ethernet applications. We supply 1.25G DWDM SFP modules are hot pluggable and digital diagnostic functions area vailable via an I2C serial bus specified in the SFP MSA SFF-8472. The DWDM SFP transceiver has undergone rigorous qualification and certification testing to provide End-to-End Compatibility using switching equipment from CISCO, BROCADE, JUNIPER, ALCATEL, HP (select models), NORTEL, EMC, QLOGIC and other OEMs.

Fiber optic patch cord info from http://www.jfiberopt.com

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

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