Author: Fiber-MART.COM

eShop of Fiber Optic Network, Fiber Cables & Tools

How to choose EPON Equipment

by http://www.fiber-mart.com

OLT detail parameter
  How to choose a suitable FTTH EPON equipment,especially for EPON OLT,which is a quite headache purchasing problem in fiber optic projects and daily telecom application,for its set of complicate technical specification parameters.
This blog post is trying to list all kinds of EPON （OLT/ONU）series product technical specifications and standards in detail,which will mainly focus on those interesting parameters by our buyers. Today we mainly introduce the follows factors:
 Device parameters
 Performance and capability
 EPON Interface (downlink) index
 Ethernet optical/electrial (uplink) interface
 Debug interface (OAM)
  For better understanding full list of those technical specifications:such as device size,weight,operating environment and power parameter etc,we pick up a OLT device from FOT(Fiber Optic Telecom) EPON Product line,as an example/reference,in this whole post.
  Here is introducing a high volume OLT device,one of FOT EPON OLT family members-8040F.
1.25Gbit/s EPON interface
  What is EPON interface?The EPON interface is the one interconnected between OLT and ONU,speed can reach to 1.25Gbit/s both in uplink and downlink directions.The table “EPON Ethernet optical interface”(below) introduces the interface technical indicators of FOT’s  OLT series in detail.
Ethernet optical interface
As we know,besides the downlink direction to ONU device via EPON interface,OLT also have another direction,uplink to local Telecom vendor’s network,like ” city Metro IP Network”.This Ethernet optical interface and the following Ethernet electrical interface belong to the OLT’s uplink direction category.
 Instruction：Ethernet optical interface indicator is decided by optical module. Above indicators only for reference.
After showing those  six “Performance,Capability and Interface parameters indicator” tables above,hoping it helps our readers to build a  brief structure & profile of EPON equipment,especially for OLT device.So next time,before decide how to choose a FTTH EPON and related product,we could read this “structure & profile” in mind.

10G? XFP? Fiber Optic Transceiver Module

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10G? XFP?
  The XFP (10 Gigabit Small Form Factor Pluggable) is a standard for transceivers for high-speed computer network and telecommunication links that use optical fiber. It was defined by an industry group in 2002, along with its interface to other electrical components, which is called XFI.
XFP’s Applications
10GBASE-LR/LW 10G Ethernet
1200-SM-LL-L 10G Fibre Channel
 XFP modules are hot-swappable and protocol-independent. They typically operate at near-infrared wavelengths (colors) of 850 nm, 1310 nm or 1550 nm. Principal applications include 10 Gigabit Ethernet, 10 Gbit/s Fibre Channel, synchronous optical networking (SONET) at OC-192 rates, synchronous optical networking STM-64, 10 Gbit/s Optical Transport Network (OTN) OTU-2, and parallel optics links. They can operate over a single wavelength or use dense wavelength-division multiplexing techniques. They include digital diagnostics that provide management that were added to the SFF-8472 standard. XFP modules use an LC fiber connector type to achieve higher density.
XFP’s Standard
  The XFP specification was developed by the XFP Multi Source Agreement Group. It is an informal agreement of an industry group, not officially endorsed by any standards body. The first preliminary specification was published on March 27, 2002. The first public release was on July 19, 2002. It was adopted on March 3, 2003, and updated with minor updates through August 31, 2005. The chair of the XFP group was Robert Snively of Brocade Communications Systems, and technical editor was Ali Ghiasi of Broadcom. The organization’s web site was maintained until 2009.
Description:
  (Make FOT’s FX-3110G-ERC as an example) Small Form Factor 10Gb/s (XFP) transceivers are compliant with the current XFP Multi-Source Agreement (MSA) Specification. They comply with 10-Gigabit Ethernet 10GBASE-LR/LW per IEEE 802.3ae and 10G Fibre Channel 1200-SM-LL-L. Digital diagnostics functions are available via a 2-wire serial interface, as specified in the XFP MSA.
Features:
Supports 9.95Gb/s to 10.5Gb/s bit rates
Hot-pluggable XFP footprint
Maximum link length of 40Km on SMF
Uncooled 1310nm DFB laser.
Duplex LC connector
Power dissipation <2.5W
No Reference Clock required
Built-in digital diagnostic functions
Temperature range -5°C to 70°C
Very low EMI and excellent ESD protection
Fully compliant to XFP MSA Rev.4.5
RoHS Compliant Part

Understand the handheld fiber optic microscope in minutes

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What is a digital microscope?
A digital microscope is a variation of a traditional optical microscope that uses optics and a digital camera to output an image to a monitor, sometimes by means of software running on a computer. … Since the image is focussed on the digital circuit the entire system is designed for the monitor image.
The handheld fiber optic microscope
Reliability and performance of a fiber optic link largely depends on the quality of interconnects. Contaminated connectors can cause the mating surfaces to separate leading to high insertion loss and back-reflection. Furthermore, some dirt particles can even scratch or dig into the glass causing permanent damage to the end-face of the connector. Therefore, inspection of fiber optic connectors should be performed whenever a connection is to be made.
The handheld microscope specifically designed for fiber optic connector end face inspection.
Features
FC/SC/ST/E2000/LC/MU/MPO compatible
3.5-inch TFT display
Up to 250x overall magnification
4x digital zoom
SD card storage up to 8G
Snapshot, video recording and playback
PC plug-and-play

Learn about optical repeater transmission system in minutes

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The transmission distance of any optical fiber communication system is limited by the factors such as optical fiber loss and dispersion. The optical fiber communication network system, like the telecommunication network, must add a regenerative relay station at a certain distance to complete the transmission of signals during long-distance long-distance transmission. The amplification and regeneration to ensure signal transmission quality. In optical fiber transmission links, in addition to using various active devices with different functions, the quality of optical passive devices has an impact on the performance of optical fiber networks.
Learn about types of Optical-electrical-optical repeater
  Absorption and dispersion of the optical fiber result in attenuation of the optical signal and waveform distortion, and therefore, the quality of information transmission is reduced, the bit error rate is increased, and the communication distance is limited. In order to meet long-distance communication requirements, there are usually two methods for the relay transmission of optical signals: First, an optical-electric hybrid repeater used in the early days, and an optical-electrical-optical conversion method is adopted, and its structure is shown in the following figure. Attenuation and distortion of the optical signal will be received by the optical receiver, and converted to electrical signals for processing, and then modulate the optical transmitter light source, convert the optical signal to continue transmission; Another method is to use optical amplifier to light The signal is amplified directly and transmitted.
Optical-electrical-optical repeater structure
  Early (and still widely used) optical fiber relays use optical-electrical-optical conversion. The structure of a typical digital optical repeater is shown in the figure below, mainly consisting of a photodetector, an electrical signal amplifier (a low noise preamplifier and a high gain main amplifier), an equalizer circuit, an automatic gain controller (AGC) circuit, and a decision Regeneration circuit, light modulation circuit and light source.
Light-electric-light conversion process
  The photodetector is used to sense the received optical signal, convert it into an electrical pulse signal, and then through an electrical signal amplifier for amplification, regeneration decision processing, etc., to restore the same digital signal stream as the transmission end, and then pass The light modulator modulates the light source, converts it into an optical signal and enters the optical fiber to continue transmission. That is, each relay station processes the transmitted optical signal using an optical-electrical-optical conversion method.
Optical-electric-optical repeater functional modules
  From the composition of the repeater, the main functional modules can be summarized as follows.
Balanced magnification. It means that the distorted weak electrical signal that is input is equalized, compensated, shaped and amplified to a certain extent to meet the signal processing requirements.
Timing extraction circuit. It refers to extracting the clock frequency from the input electric pulse signal sequence to obtain the timing pulse for use in circuits such as synchronous demodulation.
Decision regeneration circuit. It refers to regenerating the transmission distortion waveform to obtain the same electrical pulse sequence shape process as the transmission end.
  The most important feature of this repeater is that it can shape and regenerate the pulse signal so that the distortion of the waveform will not be accumulated. The inadequacies are complex equipment, high costs, and inconvenient maintenance.
All-optical repeater
  The optical-electrical-optical conversion repeater technology is relatively mature, but its disadvantage is that the equipment is complex and the cost is high, and it is also a bottleneck of the signal transmission link (the electric signal bandwidth is much narrower than the optical signal bandwidth). With the development of optical device technology, it has been developed to directly amplify and relay optical signals.
 Prior to the advent of optical fiber amplifiers, repeaters of optical fiber communication systems used optical-electrical-optical conversion methods without exception. This resulted in the complexity of equipment in communication systems, which resulted in high costs and reduced capacity. As a result, the efficiency of the system was reduced. Increased network costs and other issues. Therefore, scientists have long been devoted to the study of all-optical relays, that is, direct optical amplification repeaters that do not require optical-electrical-optical conversion. The emergence of optical fiber amplifiers is an important milestone in the history of optical fiber communications. The development trend of optical fiber communication systems is to realize all-optical networks. Optical amplifiers are directly used to amplify optical signals. The amplification process is shown in the figure.
  An all-optical repeater, ie, an optical amplifier, is characterized by directly amplifying the optical signal and has a high degree of transparency to the signal pair format and rate (because the optical amplifier only amplifies the received signal, so it can support various bit rates and any The format of the signal) makes the system structure simple and flexible.
  Optical amplifiers mainly include semiconductor optical amplifiers (SOAs) and fiber amplifiers. The title optical amplifier refers to an optical amplifier device made of a semiconductor material. If the reflection film at both ends of the semiconductor laser is removed, that is, a semiconductor traveling wave optical amplifier without feedback, it can amplify light of different wavelengths. Fiber amplifiers include two types: nonlinear fiber amplifiers and doped fiber amplifiers. The doped fiber amplifier is an optical amplifier developed in recent years. It utilizes a rare-earth metal ion doped (Er), neodymium (Nd), praseodymium (Pr), ytterbium (Tm), etc. doped with a rare- The ions are incorporated into the optical fiber, and the pump light source is externally applied to meet certain conditions to constitute an optical amplifier. Common doped fiber amplifiers (1.55 μm operating band), Erbium doped fiber amplifiers (1.3 μm working band), Erbium-doped fiber amplifiers (1.55 μm working band), etc.

Learn to choose the right fiber in minutes

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How to select a right optical fiber?
  The basic requirement when selecting the optical fiber is that the optical power coupled into the optical fiber from the emitting light source should be large enough, and the distortion generated after the optical signal is transmitted through the optical fiber is minimal.
Low transmission attenuation
  In a particular wavelength range, the attenuation must be small enough to allow the relay distance to be as long as possible while meeting the optical power required by the receiver. When designing the system, consider the insertion loss of connectors, connectors, and couplers, and the amount of headroom required for system operation. For this reason, the correct choice of operating wavelength and fiber type.
Low coupling loss
  Coupling losses include light source coupling loss and detector coupling loss. When the core size and numerical aperture are large, the coupling loss of the light source can be reduced, but the detector coupling loss increases. In order to reduce the coupling loss with the detector, it is required that the core size and the numerical aperture be sufficiently small so that the outgoing light of the optical fiber completely falls on the receiving surface of the detector. In order to improve the response speed of the receiver and reduce the noise, the area of ​​the detector is required to be small, so the method of increasing the photo-sensitive surface of the detector cannot be used to reduce the coupling loss. Fibers with a large core size and numerical aperture have a small transmission bandwidth and are suitable for systems using LEDs.
Low connection loss
  Connection losses include loss of connectors and connectors. The core diameter tolerance, out-of-roundness, and core and cladding concentricity errors are as small as possible to obtain the minimum connection loss. To increase the geometrical accuracy of the optical fiber, it is necessary to increase the manufacturing cost. Increasing the size of the core and the numerical aperture can reduce the adverse effect of the geometrical tolerance on the connection loss, but it is inconsistent with the increase of the bandwidth and a comprehensive consideration must be taken for the compromise.
Dispersion and bandwidth
  In order for the modulated optical signal to pass through the full length of the optical fiber with minimal distortion, the dispersion of the optical fiber is required to be sufficiently small. In order to reduce fiber dispersion, the refractive index distribution index and the zero dispersion wavelength must be strictly controlled. For a specific system, the fiber type and working wavelength should be selected correctly. For example, a long-distance, high-rate submarine cable system should use a G.654 fiber with a zero-pigment shift of 1.55 μm. The wavelength-division multiplexing system should choose a small dispersion system. However, the non-zero but G.655 fiber reduces the four-wave mixing but has an adverse effect. The DWDM system used in the metropolitan area network must be a full-wave fiber with an extremely wide wavelength range and a wide range of available wavelengths. Systems using LEDs must fully consider the effects of material dispersion and other factors. The table above shows the typical parameters of a zero-cable single-mode fiber for reference when selecting the fiber.

What Makes Fiber Optic Cables Future Proof?

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Internet connectivity over an optical cord has become a precious standard for fast and high-quality data transmission. This technology is relatively new. This new nature of it can leave some in a dilemma. Some would even be unwilling to invest in it. Some would still prefer go old school and use convention network cables.
Over the years, with the technical progress, even conventional cable has risen to new horizons. But, which technology is better? Both copper and glass or optical cords have their benefits. Both have unique features. If something is better for others does not necessarily make it better for you. So, the right question to ask is which means would suit your business?
Fiber Optics Cable
The conventional copper wires transmit data via electricity. Fiber wire relies on light. It does not transmit data through the flow of electrons. This enables much faster internet connection. In fact, it also enables handling of a higher bandwidth. Sometimes, even during the peak demand, the performance of fiber wire stands out.
The cost of optical deployment has seen a dramatic reduction recently. Moreover, the fiber optic cable is future proof. This gives it an edge over the use of copper cables. It surely has a better prospect in the world market. Let us compare fiber and copper on these five determinants to decide which one is better and suits your purpose.
Cost
As mentioned above, the cost of fiber components has seen a decrease recently. Once, the cost of optical cord was twice that of a copper wire. Now the cost difference is minimal. In fact, if we consider the overall cost, copper cable can get costlier. This is if we consider the cost of wiring closet. This includes cost of uninterrupted power source, data ground and HAVC (Hybrid Automatic Voltage Control). Overall, an all fiber LAN is more cost efficient than a copper-based network.
Bandwidth
Copper is sufficient for voice signals. Even though it has a limited bandwidth of up to 60Gbps. Fiber cords are capable to provide 1000 times as much bandwidth as copper. It can also travel for a longer distance in lesser time. In simple terms, a 500-meter fiber wire can transmit 1GHz. Whereas, a twisted pair copper wire (Cat 6) can transmit 500Mhz just up to 100 meters. Moreover, the signal loss is negligible in an optical cable. Copper has higher losses at higher frequencies. It is also noisy.
Transmission Speed & Distance
This is literally the battle between photons and electrons! Photons do not achieve 100% efficiency in achieving the speed of light. But, even with 31% slow speed, it is much faster than the speed of electrons. You cannot overlook the significant difference which exists between fiber and copper. Moreover, copper wires also have the limitation of 100 meters. This is not the case with fiber cables. In optics, the distance can range from 550 meters for 10 Gbps single mode and up to 40 Kms for multi-mode!
Reliability
Fiber optics is not susceptible to damages from the surrounding environment. Copper has the trait of losing quality over certain distance under conditions. In fact, if we use a fiber optic cable over the same distance, under the same condition, it would provide you reliable data transmission. Moreover, fiber is immune to environmental and climatic factors. Temperature variation or any electromagnetic variation will not tarnish its performance. Copper is sensitive to these factors. You can deploy fiber optic cables near industrial equipment without worry. Likewise, you can also lay down fiber into deep oceans.
Security
One can trap the electrical signals from the copper cable. In addition, it also radiates signals. If someone traps the signals, the entire system can fail. On damages, it gets difficult to identify the leakages. In case of a fiber wire, detection of a broken wire is easier. This is because several monitoring techniques are in practice for detecting its flaws. Copper wire can cause a short circuit which can even result in a fire.
Conclusion
The usage of fiber cable with its ever reducing cost and other advantages is making it future proof. Increase in bandwidth, ridiculous increase in transmission speed and many more features make it better and reliable medium for networking. It is one of the most significant mediums for innovative installations and upgrades.