Researchers in the US, funded by the US Air Force, Defense Threat Reduction Agency (DTRA), and the National Science Foundation, have managed to turn air into an “optical fiber.” This breakthrough allows the scientists to create an air waveguide, allowing for much better transmission of lasers through free space — much in the same way that glass and plastic waveguides allow for efficient transmission of laser light over long stretches of optical fiber. As you might have guessed from the US military’s involvement, this could be big news for laser weapons — but there are repercussions for laser-based communications and scientific research as well. As we covered in our featured story, The Science of Beam Weapons, lasers really suck at traveling through air. Lasers are fine over short distances at low intensities (e.g. laser pointers), but to increase their effective range or destructive power you really have to dial up the power — and, rather annoyingly, strong lasers have so much energy that they ionize the air that they travel through, creating nasty air (blooming) that quickly causes the laser to lose coherence and fizzle. As a result, any powerful laser that might be used for long-range communications — or bisecting a battalion of enemy soldiers on the battlefield — self-destructs after just a few meters of traveling through air. This is why, for the most part, lasers are almost exclusively used in conjunction with a waveguide — such as optical fiber — that keeps the beam coherent over a long distance. Now, however, Howard Milchberg and some graduate students at the University of Maryland have created an air waveguide, allowing them to beam powerful lasers much farther through open space before they fizzle. The science is fairly complex, but essentially the waveguide is produced by a series of femtosecond laser pulses. The rapid heating caused by the laser pulses generates a ring of tiny sound waves that converge on a center point, creating a high-pressure channel in the middle surrounded by a low-pressure region. The main laser beam is then transmitted along these high-pressure channels, with the light bouncing off the lower refractive index of the low-pressure region — much in the same way that light bounces along the inside of a glass fiber.
Over a short distance in the lab, Milchberg said the waveguide boosted signal quality by 50%, which might not sound like much, but for longer distances — which is what this is all about — that should equate to a signal-to-noise ratio improvement of around 104 which is huge. As far as real-world applications go, there are dozens of scenarios that stand to make serious gains from the use of air waveguides. Milchberg and co specifically mention laser-induced breakdown spectroscopy (the technology Curiosity uses to analyze rock samples on Mars), but long-range LIDAR and the US military’s laser weapons are two other obvious applications. Outside of weaponization and scientific endeavor, air waveguides could also significantly improve the range and throughput of free-space laser networks — which are already by far the fastest and lowest latency wireless networks available. source - www.extremetech.com
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Hotline Telephone Setup
The hotline analog telephone is setup by using a pair of subscriber side modems at both ends over a fiber optics link. The fiber optics link could be either be SM or MM with a possible distance of up to 20 - 30 km depending upon modem specification. How Does Hotline Telephone Works? Simply just lift up the analog handset at one end , the analog phone located on the other end will automatically give a ring without the need to do any dialing. In typical analog phone applications, the exchange side modem and the subscriber side modem are used in pair as shown in the above diagram. These two modems are linked together using multimode fiber or singlemode fiber as per site requirement. The exchange side modem is connected via analog twisted pair telephone or RJ11 to PBX system and the subscriber side modem is connected via analog twisted pair telephone or RJ11 to analog telephone. The subscribe side modem most probably contains a ring generator whereby it generates a ring tone to the analog telephone. In most cases the exchange side modem and the subscriber side modem are both able to add in a data modem transmission of type RS422 or RS485. The data modem is connected to both modem via twisted pair cable or RJ 45 type. There many types of fiber optics modems in the market nowadays. The designer should design his or her network in accordance to availability of fiber optics modem specifications. Example of IP CCTV Network Design When to use IP CCTV and Analog CCTV?
Application of IP CCTV Solution
Application of Analog CCTV Solution
In order to design IP CCTV we need to consider in reducing cost by selecting the right IP video network and appropriate networking equipment infrastructure as IP digital video requires large amount of bandwidth and network speeds to be fast. A new type of fibre optic cable developed by researchers in the US and Netherlands has smashed data transfer records, managing to squeeze 255 terabits of information per second down a single strand of glass fibre.
This means that a single fibre optical cable made using this technology could carry as much data as the entire internet at peak times. To achieve this feat engineers from Eindhoven University of Technology and the University of Central Florida created a multi-core strand of glass fibre; a development that they say is tantamount to letting “three cars […] drive on top of each other in the same lane”. Normal fibre optic cables contain thousands of strands of glass fibre, each strand a little thicker than human hair. These transfer information by bouncing beams of light through the glass - imagine sending a message using morse code by flashing a torch on and off. By managing to scale down these glass fibres, cramming seven cores into a single glass strand, this new technology has achieved transfer speeds of 32 terabytes a second (a byte is eight times as big as a bit) or enough to shift 1,000 gigabytes in 31 milliseconds. This is faster than the total capacity of all the fibre optic cables currently buried under the Atlantic Ocean, but unfortunately it will most likely be decades before these speeds are useful to commercial customers – after all, those undersea cables won’t replace themselves. A cross section of the new multi-core cable showing the pathways arranged in a hexagon pattern. The findings can be read in the journal Nature Photonics Independent UK James Vincent Fiber Optics Monitoring Sensors - Road & PavementThe road & pavement fiber optics monitoring systems is designed to monitor pavement structure performance particularly in a harsh outdoor environment. It is designed to accurately measured pavement response under a moving load and provide reliable data to engineers in charge of improving structure lifetime.
A team of Swiss researchers from the Technology in Textiles (TechinTex) project are working on a new type of wound dressing which can monitor the state of a wound using fiber optic threads woven into the dressing. The fibers are designed to change color in response to changes in the acidity of the wound, which is an indicator of its healing status. It is hoped that this new approach may replace the need for swabs and laboratory testing. Currently the dressing is capable of detecting acidity changes in human blood serum, but may include enzyme monitoring in the future. The team is currently working on calibrating the light signal through a range of acidity levels. Such smart sensing dressings may offer a powerful new resource for the treatment of recalcitrant wounds such as diabetic, pressure and venous leg ulcers in the future. Click here for further reading
Why do I need OTDR Launch Fiber?
FTAA -- Fiber-To-The-Antenna
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AuthorI have been in the field of fiber optics since early 1990s. I gained fiber optics skills and knowledge via my working experience as end-user, main contractor and sub-contractor and finally as an optical fiber enterpreneur. Archives
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