标签: optical

Indoor fiber optic cable is probably fairly familiar to us, as it is a necessary element of our daily lives. However, there are other aspects to consider when installing outside fiber optic cables. Outdoor optical cables are designed to work in a variety of conditions. We will talk about five types of outdoor fiber optic cable and the applications of fiber optic cables in this article. Armored Fiber Cable Outside plant applications require armored fiber cable. To keep rodents out, they usually contain metal armor between the two jackets. It can bear crush loads, making it suitable for direct burial applications or data centers where cables are run beneath the floor or in dust and air. Because armored cables are conductive, they must be grounded appropriately. Aerial Outdoor Cable Aerial outdoor fiber optic cable is a fiber optic cable suitable for use in ducts and overhead installation points. Aerial optical cables are usually used for external installation of utility poles. Since the existing overhead pole lines can be used for installation, the laying method is very simple, thereby saving more construction costs. Aerial cables are mainly used in flat terrain, so they are easily affected by natural disasters such as typhoons, ice, floods, etc., and are also easily affected by external forces, so their quality must be very good to avoid frequent failures. Water Blocking Outdoor Cable Plenum outdoor cables are flame retardant and suitable for overhead, duct, riser installations. Transition joints are not required when entering the building from dedicated external plant cables. Plenum is the space above the ceiling of a building or below the raised floor used for heating, ventilation or air conditioning. What differentiates booster cables from other cables is the jacket material, which uses a flame-retardant, low-smoke material that will emit minimal harmful fumes in the event of a fire. By installing plenum rated cables, you can help ensure that your building’s code meets safety standards. Loose Tube Fiber Cable Multiple optical fibers are contained in a tiny plastic bucket in loose tube fiber cable. The fibers are loosely positioned in a tube that is coiled in a reverse helical pattern in the cable and is actually longer than the cable’s outer sheath. Because loose tube fiber cable provides the best protection for the fiber under high tension and can be easily protected from moisture with water blocking gel or tape, it is the most extensively used fiber optic cable for outdoor plant trunks. Submarine/Underwater Fiber Cable A submarine fiber cable is a telecommunications cable installed on the seabed between land-based stations to deliver telecommunication signals across ocean and sea stretches, as well as lakes and lagoons. The optical fiber used in subsea cables is chosen for its remarkable clarity, allowing longer distances between repeaters of more than 100 kilometers, reducing the number of amplifiers and the distortion they create. Applications of Fiber Optic Cable 1. Computer Networking 2. Cable Television 3. Internet 4. Telephone 5. Mechanical Inspections 6. Surgery and Dentistry 7. Military and Space Applications 8. Automotive Industry 9. Lighting And Decorations Baudcom offers all kinds of Outdoor Fiber Optic Cables. For more information, please feel free to contact us.

Co-axial copper cables have long been utilised as conduits of analogue RF signals but there is now a medium for electromagnetic energy that is starting to compete with coax: optical fibre. The much-lower attenuation of fibre (around 1 dB/km) compared to coax (roughly tens of dB/km) makes it especially attractive in the latter cases. Fibre's immunity to EMI/RFI is a big plus, too, especially in wide-area installations that have to deal with building motors and equipment, well-known and notorious interference sources. Key to using fibre is the RF-to-optical (aka electro-optical, or E/O) converter at the source end and the complementary optical-to-RF converter at the receiver. For the transmitter, a distributed-feedback (DFB) semiconductor laser is used when wide dynamic range and low noise are critical, while for applications with lower-performance requirements, a Fabry-Perot (FP) laser is generally chosen. At the receiver, a PIN diode captures the photons and coverts them into electrical signals.   There's an element of irony here: although we associate fibre-optic links with high-speed digital signals, as in the Gbit/sec cables and links which are the foundation underpinning the physical layer of the Internet and its data flow, this use of optical fibre for RF is entirely in the analogue domain – as so much of RF still is. Thus, the traditional analogue issues of noise, linearity, distortion, clipping, limiting, and similar play their usual roles. Once again, analogue circuitry and functions are necessary and unavoidable, and the optical drivers and receivers need to be optimized for their analogue-performance and parameters rather than the digital ones. Goodbye to eye-pattern woes, hello again to linearity headaches. Of course, using fibre is not a trivial exercise. For engineers and installers whose experience and expertise are only with coax, there's a new world of optical-cable specifications, the fibre plus the protective jacketing, optical connectors, bend radius, E/O converters and components, and more. In addition, it's often makes sense to run a fibre-optic cable assembly which has unused fibres inside for additional capacity in the future, known as dark fibre. In contrast, running extra coax in parallel with the in-use coax is much more costly and occupies much more space. Have you ever wished you had a performance- and cost-effective alternative to coaxial cable? Have you explored using analogue fibre for RF? What concerns and issues would you have from a technical as well as personal standpoint?  

Today's fiber-optic connectors have the amazing mechanical precision that allows low-loss mated pairs, especially considering that single-mode fiber has an optical core of about 9 microns in diameter. Two of these cores, from opposing fibers, must be aligned with almost-perfect mechanical precision to affect the least amount of optical loss.   Positive contact and angled polish keep losses and reflections to a minimum. Of course, this small core size means that the slightest speck of dust on the single-mode core can introduce disastrously high levels of loss, so absolute cleanliness (cleaning the end faces of the connector ferrules) is a must every time a connection is made.     It was not always this good. Quite a few years ago, optical fiber networking was becoming mainstream in the LAN arena. At that time, 50/125, 100/140, and later, 62.5/125 (core and cladding diameter in microns), multimode optical fiber sizes were the short-distance LAN choices. The large diameter core allowed optical launch using LEDs, rather than more costly and finicky lasers.   The 906 SMA optical connector was one of the first popular optical connectors, but it had a few annoyances. For example, a "Delrin sleeve" (hollow plastic cylinder) was required to mechanically align the ferrules of a mated pair, precisely enough that the loss should remain under 3 dB. Being detachable, these Delrin sleeves had a habit of falling on the floor and rolling under anything that prevented someone from ever finding them again.   Compared to today's connectors, with losses of a fraction of a dB, this 3dB loss spec was atrocious. But it was a fact of life, and we had to live with it.   One day, our lab technician was setting up the optical portion of our corporate network and ran into difficulty. He came to me for help because he was getting unexplained bit errors over all the optical links. We had just started manufacturing an Ethernet 10Base-T and FOIRL (Fiber Optic Inter Repeater Link) hub, but he was trying to use Cabletron optical transceivers at the desktop ends. Plus, he had set up an optical patch panel that added an extra mated pair per patch cord.   I had designed the optical cards for our own product. In spite of much complaining from production, I insisted on tweaks to ensure that the green "Link Good" indicator LED would not turn on unless the incoming optical signal level was sufficient to ensure a bit error rate of better than 10 -9 . This was a requirement of the FOIRL Specification.   The Cabletron folks did not want expensive tweaks, so they designed their gear with a "Link Good" indicator LED that turned on with the slightest optical input -- never mind that it was so weak that the bit error rate made the link unusable -- thus, their gear was not FOIRL compliant.   Our lab technician was fooled by the Cabletron desktop transceivers "Link Good" LEDs. I showed him, with my optical power meter, that the link was not good, and that the Cabletron LEDs were lying to him. Then I told him the only solution was to rearrange his patch panel to eliminate one of the two optical couplings -- use cord and splice bushing only, rather than splice bushing to patch cords to another splice bushing. This eliminated 2 dB to 3 dB of loss and the links worked.   Note: 3 dB of optical loss is equivalent to 6 dB of electrical loss.   Glen Chenier Engineer

One of the many astonishing aspects of today's fiber-optic connectors is the mechanical precision that allows low-loss mated pairs, especially considering that single-mode fiber has an optical core of about 9 microns in diameter. Two of these cores, from opposing fibers, must be aligned with almost-perfect mechanical precision to affect the least amount of optical loss.   Positive contact and angled polish keep losses and reflections to a minimum. Of course, this small core size means that the slightest speck of dust on the single-mode core can introduce disastrously high levels of loss, so absolute cleanliness (cleaning the end faces of the connector ferrules) is a must every time a connection is made.     It was not always this good. Quite a few years ago, optical fiber networking was becoming mainstream in the LAN arena. At that time, 50/125, 100/140, and later, 62.5/125 (core and cladding diameter in microns), multimode optical fiber sizes were the short-distance LAN choices. The large diameter core allowed optical launch using LEDs, rather than more costly and finicky lasers.   The 906 SMA optical connector was one of the first popular optical connectors, but it had a few annoyances. For example, a "Delrin sleeve" (hollow plastic cylinder) was required to mechanically align the ferrules of a mated pair, precisely enough that the loss should remain under 3 dB. Being detachable, these Delrin sleeves had a habit of falling on the floor and rolling under anything that prevented someone from ever finding them again.   Compared to today's connectors, with losses of a fraction of a dB, this 3dB loss spec was atrocious. But it was a fact of life, and we had to live with it.   One day, our lab technician was setting up the optical portion of our corporate network and ran into difficulty. He came to me for help because he was getting unexplained bit errors over all the optical links. We had just started manufacturing an Ethernet 10Base-T and FOIRL (Fiber Optic Inter Repeater Link) hub, but he was trying to use Cabletron optical transceivers at the desktop ends. Plus, he had set up an optical patch panel that added an extra mated pair per patch cord.   I had designed the optical cards for our own product. In spite of much complaining from production, I insisted on tweaks to ensure that the green "Link Good" indicator LED would not turn on unless the incoming optical signal level was sufficient to ensure a bit error rate of better than 10 -9 . This was a requirement of the FOIRL Specification.   The Cabletron folks did not want expensive tweaks, so they designed their gear with a "Link Good" indicator LED that turned on with the slightest optical input -- never mind that it was so weak that the bit error rate made the link unusable -- thus, their gear was not FOIRL compliant.   Our lab technician was fooled by the Cabletron desktop transceivers "Link Good" LEDs. I showed him, with my optical power meter, that the link was not good, and that the Cabletron LEDs were lying to him. Then I told him the only solution was to rearrange his patch panel to eliminate one of the two optical couplings -- use cord and splice bushing only, rather than splice bushing to patch cords to another splice bushing. This eliminated 2 dB to 3 dB of loss and the links worked.   Note: 3 dB of optical loss is equivalent to 6 dB of electrical loss.   Glen Chenier Engineer