Basic Common Sense Resolution of Fiber Optic Transceivers

Fiber optic transceiver is an indispensable network data transmission equipment. What is fiber optic transceiver? What is the structure of fiber optic transceivers? What is the role of fiber optic transceivers in the data dissemination process?
Fiber optic transceiver includes three basic functional modules: optical media converter chip, the optical signal interface (optical transceiver module) and the electrical signal interface (RJ45), with network management functions include network management information processing unit.
Fiber optic transceiver is a short distance twisted pair electrical signals and optical signals over long distances to swap the Ethernet transmission media conversion unit, in many places, also known as Fiber Converter. Products in generic applications can not be covered in the Ethernet cable, you must use the fiber to extend the transmission distance of the actual network environment, and is usually located in the broadband metropolitan area network access layer applications; in helping the fiber last mile connections to the metro also played a huge role in the network and the outer layer of the network.
Used directly in some of the larger companies, network construction fiber-optic backbone network established for the transmission medium, the internal LAN transmission medium is usually copper. How to implement LAN and connected to the fiber optic backbone? This requires different ports, different linear, convert between different fiber and ensure the quality of the link. The emergence of fiber optic transceivers, conversion between twisted pair electrical signals and optical signals to ensure the smooth transmission of data packets between two networks at the same time it will network transmission distance limit extended to more than 100 kilometers from the copper wire 100 meters ( single-mode fiber).
What are the basic features of fiber optic transceiver:
1. It is completely transparent to the network protocol.
2. Ultra low-latency data transmission.
3. It supports a wide operating temperature range.
4. Using a dedicated ASIC chip data wire-speed forwarding. The programmable ASIC will focus on the multiple functions onto a single chip, has the advantages of simple design, high reliability, low power consumption, enabling the machine to get higher performance and lower cost.
5. Network management equipment to provide network diagnostics, upgrades, status reports, exception reports and control functions, provide a complete operation log and alarm log.
6. Rack equipment can provide hot-swap function, ease of maintenance and uninterrupted upgrade.
7. Support a full range of transmission distance (from 0 to 120 km).
8. Equipment 1 +1 power supply design, support for ultra-wide supply voltage, power protection and automatic switching.
Fiber transceiver classification:
There are many types of fiber optic transceivers. In WDM system, for example, there are CWDM and DWDM transceivers including CWDM SFP, DWDM SFP, CWDM SFP+, DWDM SFP+, CWDM GBIC, CWDM XFP, DWDM XFP, CWDM X2, DWDM X2, CWDM XENPAK, and DWDM XENPAK.
FiberStore provides a full range of optical transceivers, such as SFP+ (SFP Plus) transceiver, X2 transceiver, XENPAK transceiver, XFP transceiver, SFP (Mini GBIC) transceiver, GBIC transceiver, CWDM/DWDM transceiver, and PON transceiver. All our fiber transceivers are 100% compatible with major brands like Cisco, HP, Juniper, Nortel, Force10, D-link, 3Com. They are backed by a lifetime warranty, and you can buy with confidence. We also can customize optical transceivers to fit your specific requirements.

PLC Splitter Production and Packaging

With the recovery of optical fiber communication industry and the development of FTTX, the spring of fiber optic splitter market is coming.

There are two types of optical splitter, which are Fused fiber splitter and PLC splitter. PLC splitter is a hot research today, with a good prospect of application. PLC splitter package, however, is the difficulty in manufacturing.

The PLC splitter Package refers to the planar waveguide splitter on the light guide path (waveguide) with the fiber in the fiber array aligned one by one, and then stick with specific adhesive (such as epoxy glue) together with the technology. Wherein the alignment accuracy of the PLC splitter and an optical fiber array is the key technology. PLC splitter package involves a six-dimensional optical fiber array and optical waveguides in close alignment difficult. When the manual, the drawback is the low efficiency, poor reproducibility, human factors and is difficult to achieve large-scale production.

PLC splitter Production
PLC splitter using semiconductor technology (lithography, etching, developing technology) production. Multi-channel optical fiber array and the optical waveguide array is located on the upper surface of the chip, branching function is integrated on-chip is a chip on the splitter 1,1; Then, the ends of the chip, respectively coupling the input terminal and an output terminal package.

Compared with Fused Splitter, PLC splitter has these advantages: (1) loss wavelength is not sensitive to light, to meet the different wavelengths of the transmission needs. (2) spectroscopic uniform signal can be uniformly allocated to the user. (3) compact structure, small size, can be installed directly in the various existing junction box, without leaving a lot of space for installation. (4) only a single device shunt channel can achieve much more than 32 channels. (5) The multi-channel, low cost, stars ones more and more obvious cost advantages.

At the same time, the main drawback of the PLC splitter: (1) device fabrication process complexity, high technical threshold, the chip by several foreign companies to monopolize the domestic bulk package produced by very few companies. (2) relative to the higher cost of Fused Splitter more at a disadvantage, especially in the low channel splitter.

PLC splitter Packaging Technology
PLC splitter package process includes coupling alignment and bonding operations. Coupling of the PLC splitter chip and the optical fiber array is aligned with both manual and automated, and they depend on the hardware with the six-dimensional precision trimming frame, the light source, power meter, microscopic observation system, while the most commonly used are self-aligned , it is through the optical power feedback closed-loop control is formed, and therefore high coupling efficiency docking accuracy and docking.

PLC splitter has 8 channels and each channel must be accurately aligned to ensure that the relative position between the respective channels due to the manufacturing process of the waveguide chip and an optical fiber array (FA), so only the PLC splitter and the first channel of the FA and 8-channel simultaneous alignment can ensure that other channel aligned, thus reducing the complexity of the package. The most important in the packaging operation at the technical difficulty is the highest coupling alignment operation, it comprises two steps First Harmonic precise alignment. First tune the purpose is to enable the waveguide to light through; the purpose of precise alignment is precise positioning of the completion of the preferred optical power of the coupling point, and it is realized by the program to search the maximum optical power.

Multiplexer and Demultiplexer Based on CWDM

Before the introduction of CWDM multiplexer, it is necessary to mention the CWDM technology.
Originally, the term “coarse wavelength division multiplexing” (CWDM) was fairly generic, and meant a number of different things. In general, these things shared the fact that the choice of channel spacings and frequency stability was such that erbium-doped fiber amplifier (EDFA) could not be utilized. Prior to the relatively recent ITU standardization of the term, one common meaning for CWDM meant two (or possibly more) signals multiplexed onto a single fiber, where one signal was in the 1550 nm band, and the other in the 1310 nm band.
CWDM multiplexer is based on CWDM technology. It is a device to allow multiple optical signals at different wavelengths to pass through a single optical fiber strand. For convenience, we usually used “Mux” instead of “multiplexer” , and “Demux” instead of “deultiplexer”.
Typically, Multiplexer and Deultiplexer (Mux and Demux) are integrated in a entirety. CWDM Mux/Demux modules have 2/4/8/16/18 channels commonly, while 5/9 channels uncommonly. In FiberStore, we supply all channel CWDM Mux and Demux. Three single fiber or dual fiber connection for CWDM Mux/Demux are available. Our standard CWDM Mux/Demux package types are Plastic ABS module cassette, 19″ rack mountable box or LGX box. No matter what kind of connectors, like FC, ST, SC, LC, etc., all are available here, and we can also mix connectors on one device.
To know more about the CWDM Mux products, let me introduce one of the CWDM Mux/Demux modules to you. Here is a 18 Channels CWDM Mux and Demux by dual fiber with LGX Metal Box.
Key Features
1.Flexibility and little LGX Standard Metal Box configuration
2.Mux and Demux combined in one LGX Metal Box
3.Compliant to ITU-T G.694.2 CWDM standard
4.Accepts any data rate and any protocol on any port up to 10 Gbps, also 40 Gbps (DPSK, DQPSK) and 100 Gbps (DPQPSK)
5.Fully transparent at all data rates and protocols from T1 to 40 Gbps Completely passive, no power supply needed
6.Simple to install, requires no configuration or maintenance
8.Low-cost transceivers applicable, existing equipment can still be used ISO 9001 manufacturing facility
9.Lifetime Product Warranty
Applications

All Enterprises and Carrier with Fiber Optic Infrastructure Transmit additional applications via existing lines Connect buildings to CWDM campus ring Connect Field offices to central office Ideal solution for metro-core, metro-access and enterprises

Sample pictures



Article Source : http://www.fiberstore.com/

Filter-based Wavelength Division Multiplexer

Filter-based Wavelength Division Multiplexer (Filter WDM, or FWDM) is based on the mature membrane filter technology, with a wide channel bandwidth, low insertion loss, high channel isolation degrees and high environmental stability and reliability. It is widely used in single-mode fiber optic communication systems and DFA.
FTTX Filter WDM module is based on Thin Film Filter (TFF) technology. The Filter-Based WDM is extensively used in EDFA, Raman amplifiers, WDM networks and fiber optics instrumentation. The FWDM series is based on environmentally stable Thin Film Filters technology. The device combines or separates light at different wavelengths in a wide wavelength range. They offer very low insertion loss, low polarization dependence, high isolation and excellent environmental stability. In FiberStore, Filter-Based WDM product family covers following wavelength windows commonly used in optical fiber systems: 1310/1550nm (for WDM or DWDM optical communications), 1480/1550nm (for high-power DWDM optical amplifier and EDFA), 1510/1550nm (for DWDM multi-channel optical networks) and 980/1550nm (for high performance DWDM optical amplifier and EDFA) and 1310/1490/1550nm (for PON, FTTX and test instrument).
1310/1490/1550 FTTX FWDM is based on filter based platform for optical device. This multiplexer features ultra low loss, high isolation, and high reliability.
FiberStore 1490/1310/1550nm FTTH FWDM can realize the multiplexing and de-multiplexing of two communication signal 1490/1310 and 1550nm. It can expand the capacity of a single fiber to achieve bidirectional communication, so that widely used in optical network upgrade and expansion, or introduce new comprehensive business etc.
As you might know, GEPON system itself works on 1310/1490, so CATV signal here is delivered over same fiber using 1550nm, and FWDM is a place where all this get’s “mixed”.
Application

Mechanical Drawing

Sample Pictures

Article source : http://www.fiberstore.com/

Optical add-drop multiplexer Wikipedia

An optical add-drop multiplexer (OADM) is a device used in wavelength-division multiplexing systems for multiplexing and routing different channels of light into or out of a single mode fiber (SMF). This is a type of optical node, which is generally used for the construction of optical telecommunications networks. “Add” and “drop” here refer to the capability of the device to add one or more new wavelength channels to an existing multi-wavelength WDM signal, and/or to drop (remove) one or more channels, passing those signals to another network path. An OADM may be considered to be a specific type of optical cross-connect.
A traditional OADM consists of three stages: an optical demultiplexer, an optical multiplexer, and between them a method of reconfiguring the paths between the optical demultiplexer, the optical multiplexer and a set of ports for adding and dropping signals. The optical demultiplexer separates wavelengths in an input fiber onto ports. The reconfiguration can be achieved by a fiber patch panel or by optical switches which direct the wavelengths to the optical multiplexer or to drop ports. The optical multiplexer multiplexes the wavelength channels that are to continue on from demultipexer ports with those from the add ports, onto a single output fiber.
All the light paths that directly pass an OADM are termed cut-through lightpaths, while those that are added or dropped at the OADM node are termed added/dropped lightpaths. An OADM with remotely reconfigurable optical switches (for example 1×2) in the middle stage is called a reconfigurable OADM (ROADM). Ones without this feature are known as fixed OADMs. While the term OADM applies to both types, it is often used interchangeably with ROADM.
Physically, there are several ways to realize an OADM. There are a variety of multiplexer and demultiplexer technologies including thin film filters, fiber Bragg gratings with optical circulators, free space grating devices and integrated planar arrayed waveguide gratings. The switching or reconfiguration functions range from the manual fiber patch panel to a variety of switching technologies including microelectromechanical systems (MEMS), liquid crystal and thermo-optic switches in planar waveguide circuits.
Although both have add/drop functionality, OADMs are distinct from add-drop multiplexers. The former function in the photonic domain under wavelength-division multiplexing, while the latter are implicitly considered to function in the traditional SONET/SDH networks.
Article source : Wikipedia.org

Optical attenuator Wikipedia

An optical attenuator is a device used to reduce the power level of an optical signal, either in free space or in an optical fiber. The basic types of optical attenuators are fixed, step-wise variable, and continuously variable.
Applications
Fiber optic attenuator is used in applications where the optical signal is too strong and needs to be reduced. Optical attenuators are commonly used in fiber optic communications, either to test power level margins by temporarily adding a calibrated amount of signal loss, or installed permanently to properly match transmitter and receiver levels.
For example, in a multi-wavelength fiber optic system, you need to equalize the optical channel strength so that all the channels have similar power levels. This means to reduce stronger channels’ powers to match lower power channels. Another example is when the received optical power is so strong that it saturates the receiver, you need an optical attenuator to reduce the power so the receiver can detect the signal correctly.
Fiber optic attenuators are usually used in two scenarios. The first case is in fiber optic power level testing. Optical attenuators are used to temporarily add a calibrated amount of signal loss in order to test the power level margins in a fiber optic communication system. In the second case, optical attenuators are permanently installed in a fiber optic communication link to properly match transmitter and receiver optical signal levels.
Optical attenuators are typically classified as fixed or variable optical attenuator.
Fixed optical attenuators used in fiber optic systems may use a variety of principles for their functioning. Preferred attenuators use either doped fibers, or mis-aligned splices, since both of these are reliable and inexpensive. Inline style attenuators are incorporated into patch cables. The alternative build out style attenuator is a small male-female adapter that can be added on to other cables.
Variable optical attenuators generally use a variable neutral density filter. Despite relatively high cost, this arrangement has the advantages of being stable, wavelength insensitive, mode insensitive, and offering a large dynamic range. Other schemes such as LCD, variable air gap etc. have been tried over the years, but with limited success.
For precise testing purposes, engineers have also designed instrument type variable optical attenuators. They have high attenuation ranges, such as from 0.5 dB to 70dB. They also have very fine resolution, such as 0.01dB. This is critical for accurate testing.
Variable optical attenuator instrument calibration is a major issue. The user typically would like an absolute port to port calibration. Also, calibration should usually be at a number of wavelengths and power levels, since the device is not always linear. However a number of instruments do not in fact offer these basic features, presumably in an attempt to reduce cost. The most accurate variable attenuator instruments have thousands of calibration points, resulting in excellent overall accuracy in use.

Erbium-doped Fiber Amplifier

Optical amplifier is an optical communication system device. It amplifies an optical signal directly, without converting an optical signal into an electrical signal.
Erbium-doped fiber amplifier (EDFA) is the first successful optical amplifier invented by the UK Southampton University and JP Tohoku University. It is one of the greatest invention in optical communication. Erbium-doped optical fiber is incorporated a small amount of a rare earth element erbium (Er) ion. It is the core of the EDFA. From the late 1980s, the EDFA research has been making a major breakthrough continuously. As WDM technology greatly increases the capacity of optical communication, it becomes the most widely used optical amplifier device in the optical fiber communication.
Principle
EDFA is constituted by a period of erbium-doped fiber (about 10-30m) and pump light source. The stimulated emission of erbium-doped fiber under the action of the pump light source (wavelength 980nm or 1480nm), and the radiation of light varies with the change of the input optical signal, which is equivalent to the input optical signal the amplification. Studies have shown that the erbium-doped fiber amplifiers are typically 15-40dB of gain can be obtained, and the distance relay can be increased on the basis of the original more than 100km. So, why did scientists use erbium-doped fiber element to increase the intensity of light? We know that erbium is a kind of rare earth elements, and rare earth elements has its special structural features. Over the years, people have been using the method which doped rare earth elements in optical devices to improve the performance of optics, so this is not an accidental factor. In addition, why is the pump source wavelength chosen from 980nm or 1480nm? In fact, the pumping light source wavelength could be 520 nm, 650nm, 980nm and 1480nm. But the practice has proved that the 1480nm wavelength pumping light source laser efficiency is the highest, followed by the 980nm wavelength.
Advantages
The main advantage of EDFA is a high gain, wide bandwidth, high output power, high pumping efficiency, low insertion loss, and not sensitive to the polarization state.
1. Its amplifying area happens to coincide with the minimum loss area of single-mode fiber. This reduces the transmission loss of the light signal which can be transmitted relatively far distance.
2. It is transparent to digital signal format and data rate.
3. Its amplification bandwidth is so wide that dozens or even hundreds of channels can be transmitted in the same fiber.
4. It has low noise figure close to the quantum limit, which means that multiple amplifiers can be cascaded.
5. Its gain saturation recovery time is long, and has a very small crosstalk between the respective channels.
Applications
When EDFA is used in conventional optical digital communication system applications, we can save a lot of optical repeaters, and the distance relay could also be increased significantly, which is of great significance for the long-haul fiber optic cable trunking systems.
The main applications include:
1. It can be used as the light distance amplifier. Traditional electronic fiber optic repeater has many limitations. Such as a digital signal and the analog signal conversion, the repeater should be changed accordingly; repeater changes after the device is changed from a low rate to a high rate; only transmit the same wavelength of the optical signal, and the complex structure, expensive, and so on. Erbium-doped fiber amplifier to overcome these shortcomings, not only do not have to change with the change in the way of the signal, and equipment expansion or for optical wavelength division multiplexing, no need to replace.
2. It can be used for the transmitter amplifier and the optical receiver preamplifier. For the rear of the optical transmitter amplifier, the transmit power of the laser is increased from 0dB to +10 db. Optical receiver preamplifier, the sensitivity can also be greatly improved. Therefore, only the line of 1-2 erbium-doped amplifier, the signal transmission distance can be increased to 100-200km. In addition, the erbium-doped fiber amplifier problem to be solved the unique advantages of the erbium-doped fiber amplifier has been recognized by the world, and to be more widely used. However, the erbium-doped fiber amplifier there are also some limitations. For example, in the long-distance communication can not drop channel, each station business contacts is more difficult, not easy to find fault, pumping light source life is not long, as the optical fiber communication technology continues to progress, these problems will be satisfactorily resolved.