Considerations About Fiber Optic Transceiver Designing

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

The rapid expansion of fiber optic networks, including data services measured by data volume or bandwidth, shows that fiber optic transmission technology is and will continue to be a significant part of future networking systems. Network designers are becoming increasingly comfortable with fiber solutions, since the use of which allows for more flexible network architecture and other advantages, such as EMI (Electromagnetic Interference) resilience and data security. Fiber optic transceivers play an really important role in these fiber connections. And while designing fiber optic transceivers, three aspects need to be considered: environmental situation, electrical condition and optical performance.
What Is a Fiber Optic Transceiver?
The fiber optic transceiver is a self-contained component that transmits and receives signals. Usually, it is inserted in devices such as routers or network interface cards which provide one or more transceiver module slot. The transmitter takes an electrical input and converts it to an optical output from a laser diode or LED. The light from the transmitter is coupled into the fiber with a connector and is transmitted through the fiber optic cable plant. Then the light from the end of the fiber is coupled to a receiver where a detector converts the light into an electrical signal which is then conditioned properly for use by the receiving equipment. There are a full range of optical transceivers available in telecommunication market, like SFP transceiver, SFP+ transceiver (eg. SFP-10G-SR shown below), 40G QSFP+, 100G CFP, etc.
Designing Considerations
It’s true that fiber links can handle higher data rates over longer distances than copper solutions, which drive the even wider use of fiber optic transceivers. While designing fiber optic transceivers, the following aspects should be taken into consideration.
Environmental Situation
One challenge comes to the outside weather—especially severe weather at elevated or exposed heights. The components must operate over extreme environmental conditions, over a wider temperature range. The second environmental issue related to the fiber optic transceiver design is the host board environment which contains the system power dissipation and thermal dissipation characteristics.
A major advantage of the fiber optic transceiver is the relatively low electrical power requirements. However, this low power does not exactly mean that the thermal design can be ignored when assembling a host configuration. Sufficient ventilation or airflow should be included to help dissipate thermal energy that is drawn off the module. Part of this requirement is addressed by the standardized SFP cage which is mounted on the host board and also serves as a conduit for thermal energy. Case temperature reported by the Digital Monitor Interface (DMI), when the host operates at its maximum design temperature, is the ultimate test of the effectiveness of the overall system thermal design.
Electrical Condition
Essentially, the fiber transceiver is an electrical device. In order to maintain error free performance for the data passing through the module, the power supply to the module must be stable and noise-free. What’s more, the power supply driving the transceiver must be appropriately filtered. The typical filters have been specified in the Multisource Agreements (MSAs) which have guided the original designs for these transceivers. One such design in the SFF-8431 specification is shown below.
Optical Performance
Optical performance is measured as Bit Error Rate, or BER. The problem facing designing optical transceiver lie in the case that the optical parameters for the transmitter and receiver have to be controlled, so that any possible degradation of the optical signal while traveling along the fibers will not cause poor BER performance. The primary parameter of relevance is the BER of the complete link. That is, the start of the link is the source of the electrical signals which drive the transmitter, and at the end, the electrical signal is received and interpreted by the circuitry in the host by the receiver. For those communication links which use optical transceivers, the primary goal is to guarantee BER performance at different link distances, and to ensure broad interoperability with third party transceivers from different vendors.

Fiber Optic Access Network Will Be The Main Force Of Internet Information Highway In The Future

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

As with the rapid development of social information, fiber optic technology and devices which are dedicated to provide transfer of a new business for WAN and fiber optic access network. Developments of MSTP and PON are the most representative. They are also the best solution to provide various new business in the MAN and fiber optic access network which are based on fiber optic transmission technology. As water to the fish, the developments of fiber optic access technology can not without the support and development of fiber optic access devices.
Due to the constantly updated fiber optic access technology and more and more manufacturers’ accession, nowadays the fiber optic access devices categories are more and more obvious, mainly divided into three categories:
Fiber optic connection elements, it is applied into telecommunications and computer network terminal connections, related product: Fiber optic patch cable, fiber optic connector and so on.
Fiber optic transceiver, it is utilized for computer network data transmission, related products: Fiber optic splitter, fiber patch panels and so on.
Fiber optic engineer devices and fiber optic testers, it is specially for large-scale project, related products: Fiber optic fusion splicer, fiber optic testers.
Next we will introduce these three fiber optic access devices with a representative products respectively, they are fiber patch cables, fiber optic splitter, fiber optic fusion splicer.
Fiber optic patch cable (shown as the figure)is fiber optic cable or fiber optical unit which without fiber optic connector, it is used in fiber distribution frames on various link roads. Fiber patch cables are also used in long distance local optical network, data transmission and private network, various testing and control system.
Fiber optic splitter (shown as the figure), someone calls it as fiber coupler, it belongs to optical passive components, it is used in the telecommunications networks, fiber cable television networks, subscriber loop system. Fiber optic splitters can be divided into standard coupler (double branch, unit 1 x 2, that is, the light signal into two power, for example, 1×2 fiber optic splitter, 1 x4 fiber optic splitter, 1 x 8 fiber optic splitter and so on), star/tree fiber splitters and wavelength division multiplexer (WDM, if the wavelength is a high-density separation and wavelength spacing is narrow, it belongs DWDM).
Fiber optic fusion splicer(shown as the figure) is mainly used in telecommunication for fiber optic cables construction and maintenance, it is applied into telecommunication operators, engineering companies, private network, also used in the production of optical passive and active devices and fiber optical modules for fiber splicing.
All above the fiber optic access devices highly improve the data transmission and processing capabilities of fiber optic access network, and at the same time they can bring two advantages:
First, it solved the long distance transmission problems of fiber line attachment,and made its coverage range more widely. In this way, then it can reduce the number of transit nodes through whole the coverage network, make the structure of the network easier.
Second, it satisfied people’s needs to various broadband business, and improve the quality of new business data. It solved the problem of traditional copper cable access network fundamentally and laid a good foundation for achieving the dream of FTTH. I believe that in the future, fiber optic access network will be the main force of internet information highway.

Do you know what is contained in a fiber optic transceiver module?

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

I was asked to purchase some fiber optic transceivers like SFP transceivers online. The parameters shows the working the wavelength 1310nm,1550nm, LC connector and 2km. I really don’t know what’s that means. I think I need to know their structures first. I know there are articles shows what’s fiber opitc transceiver online but they are too long and difficult to understand. I need some breif explain that could help me get the parameters. Besides, could you recommend a good manufacturer that i can turn to customize my products?
Best reply by James:
Fiber optic transceivers are characterized by three sets of performance criteria: transceiver, receiver, and transmitter which will specified in the structure of the fiber optic transceiver.
The transmitter takes in an electrical signal and then converted it into an optical one with the light source device like a laser diode or LED. The light converted from the transmitter is then coupled into the fiber with a connector and is transmitted through the fiber cable plant outside. The light from the end of the fiber is coupled to a receiver in which a detector converts the light into an electrical signal and finally adopted by the receiver equipment.
When buy fiber optic transceivers online or customize the special transceivers from the OEM manufacturer, you need to specify the cable and connector type, and requirements for wavelength, operating voltage, data rate, and bandwidth. Light source is a transmitter specification, but generally determines the choice of a cable type.
VCSEL850
LED850, 1300
Fabry-Perot Laser850, 1310(1280-1330),1550(1480-1650)
DFB Laser1550 (1480-1650)
There are some renowned manufacturer like Cisco who sell network equipments with slots that lock out transceivers from other vendors, if your device is Cisco series ones, you can go to Cisco official website but the cost maybe a little bit high, so you can try some other manufacturers like one of my provider Fiber-mart.com in China, selling full ranges of compatible transceivers. Hope it will help.

10G? XFP? Fiber Optic Transceiver Module

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

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

Comparing 40G &100G Transceivers modules

As things stand, the trend for high-speed data transmission and high-bandwidth is overwhelming.

As things stand, the trend for high-speed data transmission and high-bandwidth is overwhelming.

now, whether you believe it or not, prepared or not prepared, 40G and 100G have already on the way. To upgrade to 40G or skip it and directly migrate to 100G has become a question for many data center mangers and IT engineers

The growth in 100G comes at the expense of 10G and 40G interfaces. Infonetics says that 10G in carrier networks “is beginning a long decline after an epic 15-year run.”Meanwhile, the market for 40G is “vaporizing,” according to the market research firms.“40G transceivers are ramping up hard as data centers deploy 40GbE, particularly as a high-density 10G interface via breakout cables. 40G QSFP demand growth over single-mode fiber is primarily a result of large shipments to Internet content providers Microsoft and Google,” said Andrew Schmitt, research director for carrier transport networking at IHS Infonetics.

40G and 100G Transceiver Technical Features

40G and 100G have two main types in the data center. Short reach (SR4) for ~100 meters transmission on multimode fiber and Long Reach (LR4) for 100 meters to 10km using single-mode fiber. We can use SR/LR transceivers to connect compute clusters and various switches layers in data centers. 40G transceivers are typically deployed as four 10G lanes in QSFP or CFP MSAs. 40G SR transceiver uses 8 multi-mode fibers, VCSEL lasers, and the QSFP MSA. Using edge-emitting lasers and multiplexes the four 10G lanes onto two single-mode fibers, 40G LR4 reach a 10km distance per CFP MSA, CFP/2 or QSFP28 MSAs. The 40G SR4 and LR4 transceivers can be used in the same QSFP switch port without any issues.

40G,In today’s market, 40G products mainly include 40GBASE-SR4 and 40GBASE-LR4 QSFP+ modules and 40G AOCs. QSFP+ supports both 40G links between racks and high-density 10G links within the rack, especially the 40G QSFP+ breakout AOC which is an ideal solution for 40G migration.“40G transceivers are ramping up hard as data centers deploy 40GbE, particularly as a high-density 10G interface via breakout cables. 40G QSFP demand growth over single-mode fiber is primarily a result of large shipments to internet content providers Microsoft and Google,”said Andrew Schmitt.

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100G SR10 transceivers use 20 multi-mode fibers, VCSELs and the CXP MSA, the 100G LR4 transceivers uses CFP form and 2 single-mode fibers.The market for 100G data center optics is accelerating, but it has yet to be turbocharged by widespread data center deployment in the way 40G QSFP optics have.

The market for 100G data center optics is accelerating, but it has yet to be turbocharged by widespread data center deployment in the way 40G QSFP optics have.The data center likely will be the engine of any overall growth in optical transceiver sales over the next several years. Data centers now represent 65% of the overall telecom and datacom market for 10G/40G/100G optical transceivers. 100

100G is ready here. Tens of thousands of 100G Ethernet links deployed in core routers and carrier switches. Vast majority are CFP modules and CFP2 deployments are now starting. In addition,100G is rapidly expanding. For instance, new optical standards for the data center (100G SR4, CWDM4, PSM4) and new higher density 100G module form factors like CFP4 and QSFP28 are on the way. High port-count 100G switches are being designed and many 100G modules will be used to support high-density 10G and 25G. It is said that 100G and 4x 25G deployments are expected to grow substantially starting in 2015. 100G products mainly include 100GBASE-SR10 and 100G LR4 CFP/CFP2/CFP4 and 120G AOCs. Additionally, QSFP28 as the 100G module form factor of choice for new data center switches is also launched.

If you ask me why 40G Ethernet will be obsolete? The short answer is “cost”. From the technical point, The primary issue lies in the fact that 40G Ethernet uses 4x10G signalling lanes. On UTP, 40G uses 4 pairs at 10G each. Early versions of the 40G standard used 4 pairs, but rapid advances in manufacturing developed a 4x10G WDM on a single fiber optic pair. Each 40G SFP module contains a silicon chip that performs multiplexing so that the switch see 40 gigabits in and 40 gigabits out. It’s similar to Coarse Wave Division Multiplexing when using fiber. When you buy a 40G cable or QSFP, you are paying for the cost of the chip and software, plus the lasers, etc. When using 25/50/100G, the “lane speed” is increased to 25 gigabits per second. For 100G Ethernet, there are four 25G signalling lanes. It’s cheaper to buy 100G with four lanes rather than 40G with a four-lane MUX.

40G/100G transceivers development supports this growth with smaller module form factors for higher port density, lower power consumption per bit and lower cost per bit.

Fiber-MART offers several 40G and 100G Transceiver modules to support the transmission of very high-speed digital signals, providing a bandwidth of 40G or 100G, with distances reaching up to 40 kilometers. These include 40G CFP transceiver and 100G CFP transceivers as well as 40G QSFP+ transceivers. For more informations, you can visit www.fiber-mart.com.pls feel free to contact us for any question. E-mail : service@fiber-mart.com

How to use an optical attenuator to test the sensitivity of a fiber optic transceiver?

Do you know how to use an optical attenuator to test the sensitivity of a fiber optic transceiver?In order to maximize the performance of our fiber optic transceivers, welcome to join our Fiber-Mart editors to see how to learn this skill.

Do you know how to use an optical attenuator to test the sensitivity of a fiber optic transceiver?In order to maximize the performance of our fiber optic transceivers, welcome to join our Fiber-Mart editors to see how to learn this skill. When the optical input power is within a certain range, the optical fiber receiver has the best performance. But how can we determine if the fiber optic transceiver will provide the best performance at the lowest optical input power? One commonly used method is to use an optical attenuator such as a diaphragm attenuator. Usually only two values are needed to complete the test. The process includes the following three steps.

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1.Use a power meter to measure the optical output power of the fiber optic transmitter. Remember that industry standards define the optical input power of transmitters and receivers for specific network standards. If you are testing a 100BASE-FX transceiver,use a 100BASE-FX transmitter and the transmitter’s optical output power should be within the manufacturer’s data sheet.

2.Connect the transmitter to the receiver and verify it is operating at the maximum optical output power available from the transmitter. You need to test the receiver with the minimum optical input power that the receiver can accept, while the receiver still provides the best performance. To do this, you need to obtain the lowest light input power value from the manufacturer’s data sheet.

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3.Calculate the level of attenuation required for the test. For example, the transmitter’s optical output power is -17 dBm, and the receiver’s minimum optical power level is -33 dBm. The difference between them is 16 dB. You can use a 16 dB bulkhead attenuator at the input of the receiver and retest the receiver. If the receiver still works, it is within specification.

Note: Light loss is not considered in the above example. Assuming the transmitter is located 10 kilometers from the receiver and the loss of the entire fiber link (including the interconnect) is 6 dB, then a 10 dB bulkhead attenuator should be used instead of 16 dB for your test.

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The optical attenuator is a very important passive optical fiber device. It can attenuate the optical signal energy according to the user’s requirements. It can also be used to test the sensitivity of optical fiber transceivers. Fiber-Mart offers a full range of optical attenuators that bring convenience to users of optical communications.Any questions welcome to communicate with us: product@fiber-mart.com.