Examples of CWDM Network Deployment Solution

Based on the same concept of using multiple wavelengths of light on a single fiber, CWDM and DWDM are two important technologies in fiber optical communications. As we all know, although the transmission distance of CWDM network is shorter than that of DWDM, it costs less and has the scalability to grow fiber capacity as needed. This article intends to give a simple introduction of components in CWDM networks and to explore some examples of CWDM network deployment cases.

Common Components Used in CWDM Networks
CWDM Mux/Demux

CWDM Mux/Demux, which is based on the film filter technology, is the basic component in CWDM networks. It can combine up to 4, 8 or 16 different wavelength signals from different fiber extenders to a single optical fiber, or it can separate the same wavelengths coming from a single CWDM source. That’s why CWDM can extend existing fiber capacity.

CWDM OADM (Optical Add-Drop Multiplexer)

A CWDM OADM is a device that can add (multiplex) and drop (demultiplex) channels on both directions in a CWDM network. It can add new access points anywhere in CWDM systems without impacting the remaining channels traversing the network. With this ability of OADM, the access points can be added to liner, bus, and ring networks, where the dual direction ring design provides redundant protected architecture.

CWDM Optical Transceiver

Optical transceiver is a necessary element in optical networks. And CWDM optical transceiver is a type of module supporting CWDM network application with CWDM wavelengths. When connected with CWDM Mux/Demux, CWDM transceiver can increase network capacity by allowing different data channels to use separate optical wavelengths (1270nm to 1610nm) on the same fiber. And the common CWDM transceiver type is SFP, SFP+, XFP, XENPAK, X2, etc.

CWDM Network Deployment Solution
Example One

Description: there are five buildings (Sheriff, Courthouse, Admin, Police & Fire, & Public Works) connected via multimode fiber cables (MMF) or single mode fiber cables (SMF). These buildings are linked via multimode SFPs in an existing D-link switches to create one network for internal use of the city offices. Below is a simple graph to show the situation.

CWDM Network 1

Requirements: the goal is to install a single mode fiber network in town to connect numerous buildings. Some of these buildings have access to the city LAN. The Public Works building need to connect with Youth & Recreation Center, Library, Immanuel Lutheran School and the Senior Center. And all these buildings should have unfiltered Internet. Besides, the Waster Water Treatment Plant should be connected passing through the Senior Center. All these services are achieved using CWDM technology.

Solution: according to the requirements, this is a CWDM networks with several buildings to connect with. Here is the solution diagram.

CWDM Network

In the diagram above, we can see there is an 8CH CWDM Mux/Demux connected with the switches. According to the requirements, Youth & Recreation Center, Library, Immanuel Lutheran School and Senior Citizen Center should be connected with the Public Works and need unfiltered services. Therefore, a 4CH CWDM OADM is placed after the CWDM Mux/Demux. Then the four wavelengths will be drop and into the four buildings. In addition, another CWDM OADM is deployed in Senior center to connect the Waster Water Treatment Plant, to meet the requirement. And each site also needs to use CWDM optical transceivers.

Example Two

Description: on site A, there are three Ethernet switches and a T3 router. And their working wavelengths 1470nm, 1490nm, 1510nm, 1530nm and 1610nm. Other three sites B, C, and D also have three Ethernet switches. And a T3 router is in site E. As the following figure shows.

CWDM OADM

Requirements: Considering the cost, all the wavelengths should be transmitted on a single fiber using CWDM technology.

Solution: according to the requirements, here is a simple diagram showing the solution.

CWDM Mux Demux

In order to save cost, a 4CH CWDM Mux/Demux is used to multiplex four wavelengths (from three switches and one router) into one single fiber. At the first site B, a 1CH CWDM OADM is installed to remove one wavelength which is associated with network B. And other three sites are the same—dropping one wavelength associated with corresponding switch or router.

Summary

This article mainly introduces two CWDM network deployment examples. All the components like the CWDM Mux/Demux, CWDM OADM and CWDM transceiver are available in FS.COM. If you are interested in them, please contact us via sales@fs.com.

Related article:Differences between CWDM and DWDM

100G QSFP28 Transceiver Overview and How to Choose It

It’s no denying that today’s data centers are moving from 10G to 40G and 100G quickly. On this road, data explosion is getting faster, which result in great demand for cost-effective 100G optics. And the commonly used 100G transceivers are CFP, CFP2, CFP4 and QSFP28, especially the QSFP28. Today this article mainly introduces four types of 100G QSFP28 transceiver and the comparison between them to help you choose a suitable one.

Overview of 100G QSFP28 Transceiver
100G QSFP28 SR4 Transceiver

The 100G QSFP28 SR4 transceiver is a full-duplex optical module, offering four independent transmit and receive channels, each capable of 25Gb/s operation for an aggregate data rate of 100Gbps to 100 meters on OM4 multimode fiber (MMF). It’s fully compliant with QSFP28 Multi-Source Agreement (MSA) and can offer increased port density and total system cost savings for future data center and networking use. When connected to transmission links, an optical fiber ribbon cable is plugged into the QSFP28 modules receptacle via the MTP/MPO connector, and the guide pins inside the receptacle ensure the proper alignment. Besides, this QSFP28 transceiver offers high functionality and feature integration, accessible via a two-wire serial interface which is available for more complicated control signals and digital diagnostic information.

100G-QSFP28-SR4

100G QSFP28 LR4 Transceiver

The 100G QSFP28 LR4 transceiver is a fully integrated 4x25Gbit/s optical transceiver module, designed for use in data centers and high performance computing network links on up to 10km of single mode fiber (SMF). They are compliant with QSFP28 MSA, IEEE 802.3ba and IEEE 802.3bm CAUI-4. When connected to data transmission links, it converts four input channels of 25Gb/s electrical data to four channels of LAN WDM optical signals and then multiplexes them into a signal channel for 100Gb/s optical transmission. While on the receiver side, the module demultiplexes the 100G optical signals into four output channels and converts them into electrical data.

100G-QSFP28-LR4

100G QSFP28 PSM4 Transceiver

Defined by the 100G PSM4 MSA, PSM4 is a little different from QSFP28 SR4 transceiver. It uses four parallel lanes (four transmit and four receive) operating on each direction. Each lane carries 25G optical transmission. Therefore, eight single mode fibers are needed when PSM4 is deployed in transmission links. And the reach of PSM4 is up to 500m on single mode fiber, compensating for the transmission distance defect between QSFP28 SR4 and QSFP28 LR transceiver.

100G-QSFP28-PSM4

100G QSFP28 CWDM4 Transceiver

CWDM4 routes four 25G optical transmissions down a single fiber, which is like the PSM4. But it has longer reaches of up to 2km on SMF. And CWDM4 uses multiplexer and de-multiplexer to reduce the number of fibers to two rather than eight. When connected into transmission links, on the transmitting side, signals are multiplexed into one channel and transmitted through the SMF; then on the receiving side, the incoming signals are demultiplexed into four separated channels (shown as below).

100G-QSFP28-CWDM4

How to Choose?

With a number of 100G optical transceivers emerged, many factors should be taken into consideration when choose suitable transceivers. The key features of the 100G QSFP28 transceivers are listed below.

100g QSFP28 Transceivers

As shown in the table, cable type, interface type, fiber count and reach are needed to be considered when purchasing transceivers. For example, in the terms of reach, except the shortest (QSFP28 SR4) and the longest (QSFP28 LR4), PSM4 and CWDM4 are battling out in the 2km range. Here is a simple chart that may help to illustrate the difference between the two. As have mentioned above, PSM4 doesn’t use MUX/DEMUX, which determines its price is lower than CWDM4. However, as the transmission distance increases, the cost will grow quickly since it deploys eight-fiber transmission links.

PSM4 vs CWDM4

In summary, there are various types of 100G transceivers on the market. Different companies and operators have different requirements for their links and applications. So choosing a suitable 100G QSFP28 transceiver should be based on your practical situations. If you want to know more about 100G QSFP28 optical transceivers, welcome to visit FS.COM.

Getting to Know About QSFP-40G-UNIV Transceiver

As the switching applications requiring higher bandwidth increased, the need to upgrade from 10G to dense 40 Gigabit Ethernet switching connection also goes on rise. But the optical transceivers widely used at present require to redesign the data center layout if migrating to 40G, for the existing fiber infrastructure cannot satisfy this migration requirement. However, the QSFP-40G-UNIV transceiver can solve this problem perfectly. Why QSFP-40G-UNIV transceiver can resolve the problem successfully? Let’s first to know the basics about it.

Basics of QSFP-40G-UNIV Transceiver

The “UNIV” in item “QSFP-40G-UNIV” means “Universal”. As we all know, common optical transceiver only can operate either on single-mode fiber (SMF) or multimode fiber (MMF), but the QSFP-40G-UNIV transceiver can work on both types of fibers. Therefore, QSFP-40G-UNIV transceiver is also called SMF&MMF 40G transceiver or QSFP 40G universal transceiver. This transceiver is a pluggable optical transceiver in an industry standard QSFP+ form factor. It has four channels of 10G multiplexed inside the module to transmit and receive an aggregate 40G signal over a single pair of single-mode or multimode fiber. And it uses a duplex LC connector that makes it work with a wide range of fiber optic cables, including multi-mode OM3 and OM4 and single mode (OS1). Besides, QSFP-40G-UNIV transceiver supports distances up to 150 m over OM3 or OM4 multimode fiber and up to 500 m over single-mode fiber (different vendor may have different specifications).

ariste-qsfp-40g-univ-transceiver-1

Differences and Advantages of QSFP-40G-UNIV Transceiver

There are various types of short reach QSFP transceivers such as QSFP-40G-SR4 and QSFP-40G-XSR4. The longest reach of them on OM3 is 300m. And most of them use MPO-12 connectors and ribbon fiber infrastructure. As a result, if users have to deploy new fiber to upgrade from 10G to 40G or to install MTP/MPO fiber systems, they have to invest more money to change the existing network systems. However, QSFP-40G-UNIV transceiver is different. It has LC connectors and supports several types of cables, allowing for seamless migrations from existing 10 to 40GbE networking without requiring a redesign or expansion of the fiber network.

Here are the advantages of QSFP-40G-UNIV transceiver.

  • Uses existing duplex fiber infrastructure for 40G
  • Identical transceiver for both multi-mode and single-mode fiber for simplified operations and investment protection
  • Support for Digital Optical Monitoring (DOM) and passive network Taps for link quality monitoring and passive data analysis
  • Optically interoperable with IEEE 40GBASE-LR4 and 40G-LRL4 for easy connection to routers and switches in existing networks
  • Supported QSFP+ ports on switches without restrictions
Applications of QSFP-40G-UNIV Transceiver

As have mentioned above, QSFP-40G-UNIV transceiver is a kind of optical transceiver that can be used for both single-mode and multimode fibers. With this unique design, QSFP-40G-UNIV transceiver offers a cost-effective connectivity for data centers’ migration. Here is a simple illustration of the applications using QSFP-40G-UNIV transceivers.

Multimode Direct Connections for Cisco Switches

The following figure shows the simplest and cost-effective way to connect two Cisco Nexus 9396PX switches with Cisco compatible QSFP-40G-UNIV transceivers for multi-mode fiber infrastructure. In this connection, except for the required transceivers, an LC to LC duplex multimode fiber patch cable is also needed to link the two QSFP-40G-UNIV transceivers directly.

ci-qsfp-univ-transceiver

Single-mode 40GbE Interconnection Solution Using QSFP-40G-UNIV Transceivers

With the special characteristic, the use of Cisco compatible QSFP-40G-UNIV transceiver can help network administrators take greatly advantage of reducing deployment and support. The following figure shows a low cost single-mode 40GbE Interconnection solution. QSFP-40G-UNIV transceivers are connected with LC duplex SMF fiber patch cables. And two fiber enclosures loaded with MTP LGX cassettes and MTP/MPO trunk cables are also needed to realize this connection.

ci-qsfp-univ-transceiver-2

Conclusion

Without having to redesign or change the existing cable infrastructure, QSFP-40G-UNIV transceivers enable data centers to run at 10G today and to seamlessly upgrade to 40G. It offers a transition path between single-mode and multimode optics with lower cost and more conveniences. FS.COM supplies 40G QSFP transceivers compatible with other major brands including Cisco, Brocade, Juniper, Arista, HPE, etc. And those transceivers are 100% tested to provide a satisfying working performance. You can visit FS.COM or contact sales@fs.com for more detailed information.

Overview of Bi-Directional Transceiver Modules

During optical transmission process, it’s no wonder that using one fiber to receive data from networking equipment, and another one to transmit data to the networking equipment. This kind of transmission mode will increase investment cost certainly. Luckily, here is a type of transceiver can solve this problem. It’s bi-directional transceiver. Today, this article will take you to make sense why bi-directional transceiver can make it possible to transmit data over one fiber.

Basics of BiDi Transceiver

BiDi is short for bidirectional. BiDi transceiver is a type of fiber optic transceivers which is used WDM (Wavelength Division Multiplexing) bi-directional transmission technology so that it can achieve the transmission of optical channels on a fiber propagating simultaneously in both directions. BiDi transceiver is only with one port which uses an integral bidirectional coupler to transmit and receive signals over a single fiber optical cable. Thus, it must be employed in pairs.

How Does BiDi Transceiver Work?

The obvious difference between BiDi transceivers and traditional two-fiber fiber optic transceivers is that BiDi transceivers are fitted with Wavelength Division Multiplexing (WDM) couplers, also known as diplexers, which combine and separate data transmitted over a single fiber based on the wavelengths of the light. For this reason, BiDi transceivers are also referred to as WDM transceivers.

To work effectively, BiDi transceivers must be deployed in matched pairs, with their diplexers tuned to match the expected wavelength of the transmitter and receiver that they will be transmitting data from or to.

For example, if paired BiDi transceivers are being used to connect Device A (Upstream) and Device B (Downstream), as shown in the figure below, then:

  • Transceiver A’s diplexer must have a receiving wavelength of 1550nm and a transmit wavelength of 1310nm
  • Transceiver B’s diplexer must have a receiving wavelength of 1310nm and a transmit wavelength of 1550nm

bidi-transceiver-diagram

Common Types of BiDi Transceiver
BiDi SFP Transceiver

BiDi SFP transceiver is typically applied for the high-performance integrated duplex data link over a single optical fiber. It interfaces a network device mother board (for a switch, router or similar device) to a fiber optic or unshielded twisted pair networking cable. And the most typical wavelength combination is 1310/1490 nm, 1310/1550 nm, 1490/1550 nm and 1510/1570 nm. This BiDi SFP transceiver is used in optical communication for both telecommunication and data bidirectional communications applications.

bidi_sfp-b-1

BiDi SFP+ Transceiver

BiDi SFP+ transceiver is an enhanced SFP transceiver. It is designed for bi-directional 10G serial optical data communications such as IEEE 802.3ae 10GBASE-BX by using 1330/1270nm transmitter and 1270/1330nm receiver. And its transmission distance is up to 20 km.

bidi-sfp-plus

BiDi X2 Transceiver

BiDi X2 transceivers are designed for bi-directional 10G serial optical data communications, which likes BiDi SFP+ transceivers. The transceiver consists of two sections: the transmitter section uses a multiple quantum well 1330/1270nm DFB laser. And the receiver section uses an integrated 1270/1330nm detector preamplifier (IDP) mounted in an optical header and a limiting post-amplifier IC. This BiDi transceiver is mainly used in Ethernet network.

bidi-x2

Advantages of BiDi Transceiver

The obvious advantage of utilizing BiDi transceivers, such as BiDi SFP+ and BiDi SFP transceivers, is the reduction in fiber cabling infrastructure costs by reducing the number of fiber patch panel ports, reducing the amount of tray space dedicated to fiber management, and requiring less fiber cable.

While BiDi transceivers (a.k.a. WDM transceivers) cost more to initially purchase than traditional two-fiber transceivers, they utilize half the amount of fiber per unit of distance. For many networks, the cost savings of utilizing less fiber is enough to more than offset the higher purchase price of BiDi transceivers.

Conclusion

In summary, BiDi transceivers can combine and separate data transmitted over a single fiber based on the wavelengths of the light. That is to say, to achieve the same transmitting result, it needs less money. Except for above SFP & SFP+ BiDi transceivers, FS.COM also provides 40G BiDi transceiver. This BiDi transceiver has two 20 Gbps channels, each transmitted and received simultaneously on two wavelengths over a single MMF strand (OM3 or OM4). Any one of the transceivers would meet your different application requirements with high performance.

SFP+ Transceiver – Do You Know Its Testing Challenges?

Owing to its ubiquity, simplicity and low cost, Ethernet, one technology enabling Internet communications, is everywhere, from carrier networks to local area networks, from desktop PCs to the largest supercomputers. And with its widespread deployment, there occurs countless equipment accordingly designed for Gigabit communications, such as SFP+ transceiver. Are you familiar with SFP+? How much do you know about its testing challenges? This text will discuss some key features of SFP+ firstly, and then delve into its testing challenges.

SFP+ Transceiver Background

As an enhanced version of the small form-factor pluggable (SFP), the enhanced SFP (SFP+) is a hot-pluggable, small-footprint, and multi-rate optical transceiver accessible for up to 16 Gbit/s data communications and storage-area network (SAN) applications. And this SFP+ enjoys the following advantages.

Smaller, Cheaper, More Efficient

Just as the last paragraph mentioned above, the SFP+ module is a variant of the SFP optical transceiver. It simplifies the functionality of the 10G optical module significantly by moving functions, such as clock and data recovery (CDR), electronic dispersion compensation (EDC), 10G SERDES, and signal conditioning. Thus, the SFP+ module requires fewer components, consumes less power, and allows for increased port density. Certainly, it’s also smaller and less expensive compared with the 10-Gigabit small form-factor pluggable module (XFP) form factor.

SFP+, smaller than XFP

As SFP+ becomes more prevalent, it’s imperative for engineers to become familiar with some of the key challenges linked to testing SFP+ capable devices.

SFP+ Transceiver Testing Challenges

On one hand, SFP+ gives a hand in reducing the overall system cost. On the other, its physical layer (PHY) and performance are put with new burdens. The SERDES framer interface (SFI) between the host board and the SFP+ module displays great design and testing challenges.

  • One challenge attributes to the increased port density and the testing time required for 48 or more ports per rack. For instance, there are 15 measurements each for the host transmitter tests, and each of these measurements using manual methods can easily take from three to five minutes. This means it will take engineers more than an hour per port to complete the required tests.
  • The second one that engineers need to consider is: if a measurement fails, how can they determine which component is causing such a failure, and how they debug the issue to arrive at the root cause. Such determinations are especially challenging because of the tight physical packaging and compact designs.
  • Another challenge falls on the connectivity. That is: how to get the signal out from the device under test (DUT) to an oscilloscope. Test fixtures are typically required, but questions arise around consequently: whether the fixtures have been tested and validated against the specification.
  • The additional problem lies in the fact that the SFP+ specification requires some measurements to be performed using a PRBS31 signal. At a sampling rate of 50 Gsamples/s, the designer can acquire around 40 million unit intervals (UIs). At a sampling rate of 100 Gsamples/s, the instrument can acquire 20 million UIs. However, a PRBS31 pattern has more than 2 billion UIs. Hence, acquiring an entire pattern poses a challenge.
Conclusion

SFP+ transceiver with its compact size has become a popular industry format supported by many network component vendors. And with the above-mentioned points in mind, designers have gained an overview of SFP+ transceiver testing challenges. Fiberstore is an outstanding and professional SFP+ manufacturer and supplier, available with a sea of high-performance and -quality SFP+ transceivers. Besides SFP+transceiver, Fiberstore also supplies QSFP+ transceiver, fully compatible with major brands. For more information about transceivers, you can visit Fiberstore.

SFP+ Transceiver Testing – TWDPc Measurement

SFP+ transceiver is widely deployed in applications and becomes much more pervasive due to its smaller form factor, less power consumption and its increased port density compared with XFP transceiver. Each SFP+ transceiver houses an optical receiver and transmitter. One end of the transceiver is an optical connection complying with the 10GbE and 8GFC standards, while the other end is an SERDES framer interface (SFI) serial interconnect handling differential signals up to 10 Gbit/s. In order to keep a SFP+ transceiver achieving high performance, the engineers need to acquaint with the key challenges related to testing SFP+ transceiver. This article will first walk through the SFP+ testing challenges and then focus on one kind of testing measurement.

SFP+ Testing Challenges
  • One obvious challenge is the increased port density and the testing time required with 48 or more ports per rack.
  • Another challenge is moving seamlessly from a compliance environment to a debug environment.
  • Yet another problem most designers face today relates to connectivity: how to get the signal out from the device under test (DUT) to an oscilloscope.
  • Another challenge to prepare for is that the SFP+ specification calls out some measurements to be performed using a PRBS31 signal.
  • Additionally, acquiring a record length of 200 million data points demands huge processing power and time.
TWDPc Measurement

TWDPc, short for transmitter waveform distortion penalty for copper, requires a special algorithm defined by the SFP+ specification. This test is defined as a measure of the deterministic dispersion penalty due to a particular transmitter with reference to the emulated multimode fibers and a well-characterized receiver.

TWDPc-measurement

The TWDPc script (of 802.3aq, 10GBASE-LRM) processes a PRBS9 pattern requiring at least 16 samples per unit interval. Out of concern for the large installed base of equivalent-time oscilloscopes with a record length of around 4000 samples, the requirement for 16 samples per unit interval was relaxed to seven samples per unit interval.

The relaxation of the requirement from 16 samples per unit interval to just seven samples per unit interval causes worst-case pessimism of 0.24 dB TWDPc over 30 measurements. For DUTs that already have a high TWDPc, 0.24 dB can be the difference between a pass or a fail result.

The TWDPc measurement for SFP+ host transmitter output specifications for copper requires more than 70 Gsamples/s to capture a minimum of seven samples per UI. Real-time oscilloscopes offering higher sampling rates of 100 Gsamples/s or greater have a much higher chance of providing accurate results for TWDPc compared to scopes that only offer lower sampling-rate options.

Across the board, it is important to map the SFP+ signal’s data-transfer rate to the proper oscilloscope bandwidth requirements to ensure accuracy in measurement and margin testing. With a 10.3125-Gbyte/s data-transfer rate and minimum rise time of 34 ps, a scope with a bandwidth of 16 GHz or higher is required to meet the minimum requirements for SFP+. As noted, sampling rate is also an important consideration for the TWDPc measurement.

Conclusion

Although SFP+ transceiver simplifies the functionality of the 10G optical module, it introduces some test and measurement challenges. TWDPc is a key test for SFP+ transceiver. It defines the differences (in dB) between a reference signal and noise ratio (SNR) and the equivalent SNR at the slicer input of a reference equalizer receiver for the measurement waveform after propagating through a stimulus channel. For SFP+ compliance testing, TWDPc is a required measurement.

BiDi Transceiver Overview

For several years ago, when talked about fiber optic transceiver, almost most of people engaged in telecommunication industry would tell that a transceiver is a device comprising both a transmitter and a receiver which are combined and share common circuitry. Almost all fiber optic transceivers uses two fibers to transmit data between routers and switches. One fiber is devoted to transmitting data to the networking equipment, while the other one is devoted to receiving data from the networking equipment. For recent years, a new kind of fiber optic transceiver has been available — Bi-Directional transceiver (BiDi transceiver).

BiDi Transceiver Basis

BiDi transceiver is a type of fiber optic transceiver which uses WDM (wavelength division multiplexing) bi-directional transmission technology so that it can achieve the transmission of optical channels on a fiber propagating simultaneously in both directions. BiDi transceiver is only with one port which uses an integral bidirectional coupler to transmit and receive signals over a single optical fiber (see the following picture). BiDi transceivers are specifically designed for the high-performance integrated duplex data link over a single optical fiber and used in bi-directional communication applications. The BiDi transceivers interface a network device mother board (for a switch, router or similar device) to a fiber optic or unshielded twisted pair networking cable.

BiDi transceiver

Working Principle of BiDi Transceiver

The difference between BiDi transceivers and the two-fiber optical transceiver mainly lies in that BiDi transceivers are fitted with WDM couplers, also known as diplexers, which help to combine and separate data transmitted over a single fiber based on the wavelengths of the light. So BiDi transceivers are also called WDM transceivers. BiDi transceivers are usually deployed in matched pairs to get the work most efficiently. And the diplexers of BiDi transceivers are tuned to match the expected wavelength of the transmitter and receiver that they will be transmitting data from or to.

As can be seen from the following diagram, the paired BiDi transceivers are being used to connect two devices. Device A is used to get upstream data, and Device B is used to get downstream data. Tx means transmit. Rx means receive. The diplexer in one transceiver (Device A) should have a transmitting wavelength of 1310 nm and have a receiving wavelength of 1550 nm. The diplexer in the other transceiver (Device B) should have a transmitting wavelength of 1550 nm and have a receiving wavelength of 1310 nm.

BiDi transceiver

Advantages of BiDi Transceiver

The decisive advantage of using BiDi transceiver is that it helps to reduce the cost of fiber cabling infrastructure. This is caused by reducing the number of fiber path panel ports as well as reducing the amount of tray space dedicated to fiber management. The deployment of BiDi transceiver enables the bandwidth capacity of the optical fiber to be doubled.

Fiberstore BiDi Transceiver Solution

Fiberstore supplies a series of BiDi transceivers with different types such as BiDi SFP. These BiDi SFP transceivers support Fast Ethernet, Gigabit Ethernet, and Fibre Channel, etc. And they can be available for simplex SC or LC connector interface, which is used for data transmitting and receiving. Also, the BiDi SFPs from Fiberstore are able to support a wide range of physical media from copper to long-wave single-mode optical fiber with transmission distance up to hundreds of kilometers. The most typical Tx and Rx wavelength combinations are 1310/1490 nm, 1310/1550 nm and 1490/1550 nm. Fiberstore has a large selection of BiDi transceivers in stock. Choosing a Fiberstore BiDi transceiver can help your fiber optic network to be most economical and efficient.

40GBASE-SR4 QSFP+ Transceiver Overview

The 40G QSFP+ transceiver is a hot-swappable transceiver module which integrates 4 independent 10Gbit/s data lanes in each direction to provide 40Gbps aggregate bandwidth. 40GBASE QSFP+ transceiver provides a wide variety of high-density 40 Gigabit Ethernet connectivity options for data center and computing networks. 40G QSFP+ transceivers have various types like QSFP-40G-CSR4, QSFP-40G-PLR4, 40G QSFP+ MPO SR4 transceiver and so on. The following passages will mainly introduce the 40GBASE-SR4 QSFP+ transceiver.

Specifications of 40GBASE-SR4 QSFP+ Transceiver

The 40GBASE-SR4 QSFP+ transceiver modules support link lengths of 100m and 150m respectively on laser-optimized OM3 and OM4 multimode fibers. It primarily enables high-bandwidth 40G optical links over 12-fiber parallel fiber terminated with MPO/MTP multifiber connectors. And also, it can be used in a 4 x 10G mode for interoperability with 10GBASE-SR interfaces up to 100m and 150m on OM3 and OM4 fibers respectively. The worry-free 4 x 10G mode operation is enabled by the optimization of the transmit and receive optical characteristics of the QSFP-40G-SR4 to prevent receiver overload or unnecessary triggering of alarm thresholds on the 10GBASE-SR receiver, at the same time being fully interoperable with all standard 40GBASE-SR4 interfaces. The 4 x 10G connectivity is achieved by using an external 12-fiber parallel to 2-fiber duplex breakout cable, which connects the 40GBASE-SR4 module to four 10GBASE-SR optical interfaces. Below is a picture of 40GBASE-SR4 QSFP+ transceiver.

40GBASE-SR4 QSFP+ module with MPO connector

From the above statement, it can be seen that 40GBASE-SR4 QSFP+ transceiver uses MPO (Multi-fiber Push-On) connector to support optical links. Why use MPO connectors rather than other connectors? Please keep reading the below passage and you will get an answer.

MPO Connector Used in 40GBASE-SR4 QSFP+ Transceiver

With higher speed transmission mode, 40GbE drives the data center to run at a high-density and cost-effective style. Thus, parallel optics technology is considered to be a perfect solution for transmission due to its support of 10G, 40G and 100G transmission. The IEEE 802.3ba 40G Ethernet standard offers 40G transmission a direction by using laser-optimized OM3 and OM4 multimode fibers. Parallel optical channels with multi-fiber multimode optical fibers of the OM3 and OM4 are utilized for implementing 40G Ethernet. The small diameter of the optical fibers has no problems with the lines laying, but the ports must accommodate four or even ten times the number of connectors. So the large number of connectors cannot be covered with conventional individual connectors any more. Under this situation, 802.3ba standard incorporated the MPO multi-fiber connector for 40GBASE-SR4 because MPO connector provides a smooth transition to higher Ethernet speeds with minimum disruption and without wholesale replacement of existing cabling and connectivity components.

In fact, MPO connectors have either 12-fiber or 24-fiber array. For 40GBASE-SR4 QSFP+ transceiver, a MPO connector with 12 fibers is used. 10G is sent along each channel/fiber strand in a send and receive direction and only 8 of the 12 fibers are required and provide 40G parallel transmission as shown in below figure.

MPO connector in 40GBASE-SR4 QSFP+ transceiver

After looking through the above illustration, have you got a brief understanding of the 40GBASE-SR4 QSFP+ transceiver? Fiberstore, a leading and professional supplier in the optical communication industry, offers high quality 40G transceiver including 40G QSFP+ MPO SR4 transceiver, 40GBASE-LR4 transceiver, Cisco QSFP-40G-SR4, etc. If you are looking for a 40G transceiver. Fiberstore would be a primary choice. For more information, please visit www.fs.com.

40G QSFP Transceiver – A Great Solution For Multi-lane Data Communication

With a rapid development in the field of optical communications, the public tends to have higher requirements for the optical transceiver modules. Optical transceivers of 10G Ethernet cannot satisfy the increasing demands any more. At this time, the 40G transceiver, especially 40G QSFP transceiver, is emerged to meet the demands. The upcoming paragraphs will first introduce the concepts of QSFP and 40G Ethernet, then explain two kinds of 40G QSFP transceivers.

What is QSFP?

The QSFP (quad small form-factor pluggable) is a compact, hot-pluggable transceiver used for data communications applications. It interfaces networking hardware to a fiber optic cable and allows data rates from 4×10 Gbit/s. The QSFP specification accommodates Ethernet, Fibre Channel, InfiniBand and SONET/SDH standards with different data rate options. QSFP+ transceivers are designed to carry Serial Attached SCSI, 40G Ethernet, QDR (40G) and FDR (56G) Infiniband, and other communications standards.

40G Ethernet Standards

40 Gigabit Ethernet is a group of computer networking technology for transmitting Ethernet frames at rates of 40 gigabits per second (40 Gbit/s). It was first defined by the IEEE 802.3ba-2010 standard. The 40 Gigabit Ethernet standards encompass a number of different Ethernet physical layer (PHY) specifications. The following nomenclature is used for the physical layers.

Physical layer 40 Gigabit Ethernet
Backplane 40GBASE-KR4
7m over twinax copper cable 40GBASE-CR4
30m over “Cat.8” twisted pair 40GBASE-T
100m over OM3 MMF 40GBASE-SR4
125m over OM4 MMF 40GBASE-SR4
2km over SMF, serial 40GBASE-FR
10km over SMF 40GBASE-LR4
40km over SMF 40GBASE-ER4

According to the 40 Gigabit Ethernet standards, 40G QSFP transceivers have various types, such as QSFP-40G-LR4, QSFP-40G-SR4, QSFP-40G-PLR4 and so on. The two most common types (QSFP-40G-LR4 and QSFP-40G-SR4) will be explained in the ensuing sections.

By the 40 Gigabit Ethernet standards, QSFP-40G-LR4 supports 40 gigabit data stream over 1310nm single mode fiber through an industry-standard LC optical connector. Its link lengths can reach up to 10km. QSFP-40G-LR4 converts 4-channel 10Gb/s electrical input data to 4 CWDM optical signals, and multiplexes them into a single channel for 40Gb/s optical transmission. Reversely, on the receiver side, the module optically de-multiplexes a 40Gb/s input into 4 CWDM channels signals, and converts them to 4 channel output electrical data. QSFP-40G-LR4 is commonly deployed between data-center or IXP (Internet Exchange Point) sites.

QSFP-40G-LR4
QSFP-40G-LR4 Transceiver Module

QSFP-40G-SR4 is a type transceiver for multimode fiber and uses 850nm lasers. It supports link lengths of 100 meters and 150 meters respectively on laser-optimized OM3 and OM4 multimode fibers. It primarily enables high-bandwidth 40G optical links over 12-fiber parallel fiber terminated with MPO/MTP multifiber connectors. And also it can be used in a 4x10G mode for interoperability with 10GBASE-SR interfaces. The 4x10G connectivity is achieved by using an external 12-fiber parallel to 2-fiber duplex breakout cable, which connects the 40GBASE-SR4 module to four 10GBASE-SR optical interfaces. QSFP-40G-SR4 is intended for use short reach applications in switches, routers and data center equipment where it provides higher density.

QSFP-40G-SR4
QSFP-40G-SR4 Transceiver Module

In all, 40G QSFP transceiver modules could provide a wide variety of high density 40 Gigabit Ethernet connectivity options for data center and high performance computing networks. It is a great solution for multi-lane data communication and interconnect applications. Fiberstore has various 40G QSFP transceivers, such as QSFP-40G-LR4, QSFP-40G-SR4, QSFP-40G-CSR4, QSFP-40G-PLR4, etc. If you are looking for a 40G QSFP transceiver, Fiberstore would be a primary option.

Introduction to Cisco SFP Modules for Gigabit Ethernet

As it is known to all, Cisco is a top worldwide leader in telecommunication industry. Its products and services are excellent, which includes application networking services, optical networking, routers, switches, interfaces and modules, etc. This article will not introduce all Cisco products, only focus on Cisco SFP modules for Gigabit Ethernet.

Firstly, we should have a brief review about the term “Gigabit Ethernet”. In computer networking, Gigabit Ethernet, or marked as GbE or 1 GigE, is used to describe various technologies for transmitting Ethernet frames at a rate of a gigabit per second. It is defined by the IEEE 802.3-2008 standard. The standards for Gigabit Ethernet are as below.

Name Medium Specified distance
1000BASE-CX Shielded balanced copper cable 25 meters
1000BASE-KX Copper backplane 1 meter
1000BASE-SX Multi-mode fiber 220 to 550 meters dependent on fiber diameter and bandwidth
1000BASE-LX Multi-mode fiber 550 meters
1000BASE-LX Single-mode fiber 5 km
1000BASE-LX10 Single-mode fiber using 1,310 nm wavelength 10 km
1000BASE-EX Single-mode fiber at 1,310 nm wavelength ~ 40 km
1000BASE-ZX Single-mode fiber at 1,550 nm wavelength ~ 70 km
1000BASE-BX10 Single-mode fiber, over single-strand fiber: 1,490 nm downstream 1,310 nm upstream 10 km
1000BASE-T Twisted-pair cabling (Cat-5, Cat-5e, Cat-6, Cat-7) 100 meters
1000BASE-TX Twisted-pair cabling (Cat-6, Cat-7) 100 meters

After reviewing the Gigabit Ethernet standards, let us move on to Cisco SFP Modules for Gigabit Ethernet. According to Gigabit Ethernet standards, Cisco SFP modules for Gigabit Ethernet have many types, such as 1000BASE-T SFP, 1000BASE-SX SFP, 1000BASE-LX/LH, 1000BASE-EX, 1000BASE-ZX SFP etc. Below text will introduce the three most common types: Cisco 1000BASE-T SFP, Cisco 1000BASE-SX SFP and Cisco 1000BASE-LX/LH SFP.

Cisco 1000BASE LX/LH SFP transceiver module
Cisco 1000BASE-T SFP—Cisco GLC-T

The Cisco GLC-T is compliant with the Gigabit Ethernet and 1000BASE-T standards as specified in IEEE STD 802.3 and 802.3ab. Cisco GLC-T operates on standard Category 5 unshielded twisted-pair copper cabling of link lengths up to 100 m (328 ft). It supports RJ-45 connector. Moreover, Cisco GLC-T has low power dissipation (1.05 W typical). The operating temperature range of Cisco GLC-T is 0 to 70°C.

Cisco1000BASE-SX SFP—GLC-SX-MMD

The GLC-SX-MMD, compatible with the IEEE 802.3z 1000BASE-SX standard, operates on legacy 50 μm multi-mode fiber links up to 550 m and on 62.5 μm fiber distributed data interface (FDDI)-grade multi-mode fibers up to 220 m. It can support up to 1km over laser-optimized 50 μm multi-mode fiber cable. And GLC-SX-MMD could be connected with dual LC/PC connector. The average output power is -9.5~ -3dBm and receiver sensitivity is -17dBm. Its operating temperature range is -5 to 85°C.

Cisco1000BASE-LX/LH SFP—GLC-LH-SMD

The GLC-LH-SMD, compatible with the IEEE 802.3z 1000BASE-LX standard, operates on standard single-mode fiber-optic link spans of up to 10km and up to 550m on any multi-mode fibers. It is joint with dual LC/PC connector. And the transmit and receive wavelength ranges from 1270nm to 1355nm. The average output power of GLC-LH-SMD is -9.5~ -3dBm, too. However, the receiver sensitivity is -21dBm.

As stated above, Cisco GLC-T, GLC-SX-MMD and GLC-LH-SMD can be applied under Gigabit Ethernet and have their own features. If you are looking for all or one of them, Fiberstore is an excellent choice. Fiberstore provides fine Cisco GLC-T, GLC-SX-MMD, GLC-LH-SMD and many other SFP modules at very reasonable price.