分类： 未分类

Understanding Ports on CWDM DWDM Mux/Demux

WDM (Wavelength division multiplexing), a widely used technology that multiplexes several optical carrier signals onto a single optical fiber by using different wavelengths of laser light. To make it simple, WDM technology delivers information using multiple wavelengths over a single fiber. It is now popular with telecommunication industries for not only capacity expansion of network but also less fiber. As the basic technology of optical networking, WDM has been widely applied in optical communications. The device where the signals multiplexed and demultiplexed is called a Mux or Demux. For the ports on WDM device, how much do you know? Read on. This post will clarify the function of different ports on WDM Mux/Demux to you.

Basics of CWDM and DWDM

First of all, it is essential to talk about the basics of CWDM and DWDM before illustrating the function of ports. CWDM (Coarse wavelength division multiplexing) and DWDM (Dense wavelength division multiplexing) are different wavelength patterns of WDM systems. Though based on the same concept of using multiple wavelengths of light on a single fiber, CWDM and DWDM differ in the spacing of the wavelengths, the number of channels and the amplify the multiplexed signals in the optical space. As the name indicates, CWDM has a channel spacing of 20nm in the spectrum grid from 1270nm through 1610nm. The channel spacing of DWDM is divided into three types according to users’ needs—0.4nm, 0.8nm, and 1.6nm. Generally, CWDM is used in medium or short distance for city and access networks while DWDM is commonly applied in the long-haul distance.

Ports on CWDM And DWDM Mux/Demux

There are mainly two kinds of ports on WDM Mux/Demux—must-have ports, and special ports. Following I’ll discuss what these ports are for and how they are used.

Line Port

As a must-have port, the line port is configured on both CWDM and DWDM Mux/Demux. Each WDM Mux/Demux has a line port to transmit data. All the WDM channels are multiplexed and demultiplexed over this port. As shown in the picture above, it is feasible to either transmit combined channels through the TX port or receive the combined channels from the RX port.

Channel Ports

Channel ports are also the necessary ports to support the basic function of WDM. They transmit and receive signals on specific wavelengths. The number of channel ports varies according to the type of WDM and the wavelengths. Taking CWDM Mux/Demux as an example, since CWDM has 18 wavelengths from 1610nm through 1270nm with spans of 20nm, there will be up to 18 wavelength channel port on CWDM. However, DWDM, with narrower wavelength spans 0.4nm,0.8nm or 1.6nm of wavelengths from 1563.86nm to 1528.77nm, has up to 96 channel ports, among which 8, 16, 40, and 96 channel ports are the most common.

1310nm Port and 1550nm Port

Since the operating wavelengths of many single mode fiber optic transceivers for long-haul transmission are 1310nm and 1550nm, 1310nm port and 1550nm port, therefore, are added to WDM Mux/Demux. The 1310nm/1550nm port can add 1310nm or 1550nm wavelength to the existing network by connecting with the same wavelength optical transceiver for the network expansion need. However, as the transmission of wavelengths that are too close would interfere with each other, it should be noted that not all the WDM Mux/Demux can configure1310nm port or 1550nm port. DWDM Mux/Demux should never configure a special 1550nm port for its operating wavelength is just near 1550nm. As for CWDM, if you intend to add a 1550nm port on CWDM Mux/Demux, the five wavelengths (1510nm, 1530nm, 1550nm, 1570nm, and 1590nm) of this Mux are not accepted since the wavelength range of 1550nm port is +/-50nm, or it will cause crosstalk between signals.

Monitor Port

Monitor port is added for better network monitoring and management. It can be connected with optical power detection card, therefore easy troubleshooting can be realized. Or it can be connected with an optical power meter to check the working status of input and output signals. With the use of monitor port, network administrators can test if a signal has failed or changed without having to interrupt the existing network.

Expansion Port

Expansion port (EXP port) is not a must-have port on CWDM or DWDM Mux/Demux. With the use of the EXP port, further expansion is available. To increase the network capacity, the expansion port is connected to the line port of another C/DWDM Mux/Demux. But be careful that these two WDM Mux/Demux should support different wavelengths. For example, a CWDM Mux A with 5 channels is capable to connect another CWDM Mux B via its expansion port, but wavelengths Mux B supports should be other 13wavelengths.

Conclusion

As stated above, there are not only necessary ports but special ports with various functions. So, what special ports the Mux/Demux needs to add is all based on your need. If you have any questions or need for customized services, welcome to FS.COM and contact with us.

How to Choose the Right Fiber Optic Transceiver

With the rapid development of optical communication, there are more and more fiber optic transceivers appearing in the market to meet users’ demand to achieve various transmission rates. With so many options available, maybe you are wondering what you should pay attention to during the purchase process. This post will concentrate on the things you should know before choosing an optical transceiver, including form factors, fiber mode, etc. and I hope it can be helpful.

Basics of Fiber Optic Transceiver

Fiber optic transceiver, also called optical module, is a device that uses fiber optical technology to send and receive data. It uses electronic components to condition and encodes/decode data into light pulses and then sends them to the other end as electrical signals. As a core component in optical communication, fiber optic transceiver is widely applied in LAN, FTTH, SDH/SONET, etc. With 5th Generation wireless systems (5G) being deployed these days, the demand for high-rate optical transceivers will be increasing, especially for 100G, 200G or even 400G optical transceiver. Anyway, it’s necessary for you, who are about to choose an optical transceiver, to consider the following points.

Form Factors

Since the first optical transceiver comes on the scene, it has been constantly updated to be smaller and supports a higher data rate. Some types such as GBIC and X2 have been superseded by the newer ones. The common types that are widely used currently are 1G SFP, 10G SFP+, 40GQSFP+, 100G QSFP28, and so on. As the multi-source agreement (MSA) defines the operating characteristics of different kinds of fiber optic transceivers, it’s necessary to make a comparison among them and then choose the right one.

Fiber Mode

There are two types of fiber transceivers—Single mode fiber transceivers and multimode fiber transceivers, which are required to work with single mode fiber/multimode fiber. Most single mode fiber transceivers can work with both single mode and multimode fibers. Single mode optical fibers have a small core and the single light push virtually eliminates any distortion, thus extending the transmission distance farther than multimode optical fibers. While multimode transceivers only receive and transmit data using multimode fiber cables. It’s possible to use single mode transceiver over multimode fibers for a short distance but the signal loss is not acceptable. In a word, it is feasible but not advisable.

Transmission Distance

Generally, different fiber optic transceivers support different transmission distances. The major difference lies in the type of transceivers and fiber type. For instance, 10GBASE-LR SFP+ optical transceiver can reach up to 10km on OS2 while 10GBASE-SR SFP+ optical transceiver can only reach up to 300m when connecting with OM3. What’s more, as for multimode fiber, the transmission distance is influenced by fiber type. For example, when 100GBASE-SR is connected with OM4, up to 400m link lengths are possible, which is longer than OM3 for 300m. Besides, due to the attenuation and dispersion in the transmission, the exact distance that optical fiber can reach is limited. Therefore, you are recommended to choose transceivers that support slightly longer transmission distance than the distance you actually need.

Data Transmission Rate

The data rate largely depends on the bandwidth. There are six commonly used date rate: 155Mbps, 1.25Gbps, 2.5Gbps, 10Gbps, 40Gbps, and 100Gbps. Among them, a 155M fiber optic transceiver is referred to as FE, and 1.25G fiber optic transceiver is also called GE. Though nowadays data centers are based on 10G Ethernet architectures, the demand for higher speed and performance keeps increasing. 40G and 100G are expected to hold a larger fraction of the market share. Meanwhile, higher-speed 200G and 400G, though not mature yet, proves promising, indicating that demand for higher speed will never end in the data center.

Wavelength

Common wavelength usually comes from the range of 850 nm to 1610 nm. Following are the three common wavelengths:

  • 850nm: Multimode, low cost but short transmission distances, generally from 300-500m.
  • 1310nm: Single mode, high fiber attenuation loss but little dispersion, generally for distances within 40km.
  • 1550nm: Single mode, low fiber attenuation loss but great dispersion, generally for distances above 80km.
Compatibility

Compatibility is a crucial part to consider before purchasing a fiber optic transceiver. According to MSA (Multi-source agreement), most third-party transceivers are assembled the same specifications as first-party equipment, except for the vendor label and the price you would pay. If you search the price of transceivers by Google, you would find that third-party transceivers cost less than OEM brands. As you can match optics from various third-party vendors with OEM switches as long as they are compatible, making sure the transceiver you want is compatible with switches becomes necessary. Now there are many mature third-party suppliers in the market that provides long time warranty and technical support. FS, as one of them, provides optical transceiver tested in original brand switches to ensure the compatibility and performance of every product.

Operating Temperature

Operating temperature is also a vital part that you need to confirm before choosing a fiber optic transceiver. The optical transceiver itself will produce heat while being in use. Meanwhile, if the optical transceiver is used in a harsh environment, the temperature of the optical transceiver will inevitably change with the ambient temperature. There are three optical module temperatures: Commercial, industrial and extended, corresponding with different temperature ranges. Make sure your choice is acceptable for the environment.

Price

Perhaps you’ve been aware that the price of fiber optic transceivers varies among different vendors or brands. As mentioned above, it is feasible to use a third-party transceiver instead of the first-party one. Third-party transceivers can not only work as well as first-party transceivers but also save a large amount of money. So take your budget into consideration and check how much you would like to pay. If you are considering to choose a third-party product, authentic suppliers and high-quality products are recommended for long running.

Conclusion

In sum, it’s better to contrast and think twice before purchasing an optical transceiver for there are plenty of elements to be considered as mentioned above. If you are looking for a reliable fiber optic transceiver, FS.COM may be your ideal choice. As a professional manufacturer and supplier of compatible optical transceiver, we provide high-value products and services. For more details, visit http://www.fs.com.

Fiber Optic Cable VS. Twisted Pair Cable VS. Coaxial Cable: Which Network Cable to Use?

When you are about to install phone or network wiring, it’s inevitable to face up to the question—Which network cable should I choose? There are three main network cables: Fiber optic cables, twisted pair cables and coaxial cables. Do you know the difference among them? This article will shed light on the characteristics of the three cables and the differences you should know about them.

What Is Fiber Optic Cable?

Fiber optic cable, also known as optical fiber cable, is made up of a varying number of thin strands of optically pure glass fibers, from a few to several hundred. There are two types of fiber optic cables that are commonly used: Single mode fiber (SMF) and multimode fiber (MMF).

With a smaller diametral core, SMF provides a higher bandwidth than MMF. The small core and single light-wave result in less signal attenuation and higher transmission speed and allow data to travel farther. SMF cables are typically used in universities, colleges, CATV companies and so on. While MMF cables are typically used for relatively short distance, data and audio or video applications in LANs. On the one hand, fiber optic cables have a much greater bandwidth and longer transmission distances with low power loss. On the other hand, fiber optic cables have some drawbacks. They are more expensive to install and difficult to splice than the other two cables.

What Is Twisted Pair Cable?

Twisted pair cable is a type of copper cable made by putting two separate insulated wires together in a twisted pattern and running them parallel to each other. Cat5e, Cat6, Cat6a, Cat7 and Cat8 are the most commonly used types of twisted pair cables in the market now. As the least expensive type of LAN cable, it’s commonly used in almost every home, VoIP telephony and small or middle enterprise LANs. Compared to other form of cable, it’s not only the cheapest but easy to handle and install. However, it’s limited in distance, bandwidth and data transmission speed. Depending on whether there is a foil or mesh shield outside the cables, twisted pair cables are divided into two types: Unshielded twisted pair (UTP) and shielded twisted pair (STP).

As the name suggests, UTP cable means there is no shield and the wires just twist together while STP cable is enclosed in a metal shield. Compared to STP cables, UTP cables are less difficult to install as cables are smaller, lighter and more flexible. What’s more, UTP cables are cheaper to purchase than STP cables. Of the two twisted pair cables, UTP cable is the most commonly used for Ethernet connections. However, it’s better to choose STP if it’s in areas of high electromagnetic or radio interference. Though UTP cables reduce some EMI, STP cables work more efficiently to block interference. Therefore, STP cables are the better choice for high-speed networks.

What Is Coaxial Cable?

Coaxial cable, or coax is a type of heavy electrical cable that has an inner copper core surrounded by a tubular insulating layer, outside of which is a tubular conducting shield. Coaxial cable is insusceptible to electromagnetic interference and provides a higher bandwidth compared with twisted pair cable, but it have some disadvantages. For example, it’s bulky, expensive to install for longer distance and must be grounded to prevent interference. It is commonly used to deliver TV signals and to connect computers in a network by cable operators, telephone companies, and internet providers around the world. Depending on the diameter, coaxial cables can be divided into thinnet cable and thicknet cable.

Thinnet coaxial cable is connected using special connectors and requires to be terminated at each other. Thicknet coaxial cable is similar in construction to thinnet, however, there is an additional layer of aluminium insulation. Thicknet cable is expensive and difficult to work with but able to expand distances of up to 500 meters while thinnet coaxial cable is much thinner and flexible and it can span distances of up to 185 meters.

Which Network Cable to Use?

All of these three network cables are useful in certain areas and all of them hold their distinct advantages as well as disadvantages. Which is the best to choose depends on several factors, such as speed, bandwidth, cost, etc.

Bandwidth & distance

Both twisted pair cable and coaxial cable’s transmission of signals take place in the electrical form, only fiber optic cable transmit signals in an optical form, which makes fiber optic cable carries data at a much faster speed and wider bandwidth than the other cables. What’s more, coaxial cable should be used for short distance because signal losses are higher in it with longer distance than the other two. By contrast, the distance fiber optic cable carries data can be up to 500m as the farthest.

Cost

Generally, the installation of fiber optic cable is high because there are other optical components involved in the installation, especially optical transceivers while twisted pair cable is the most cost-effective one of the three choices. The cost of coaxial cable is higher than twisted pair cable. However, the price of the cables varies from supplier to supplier.

Installation

Professional equipment and skills are needed when installing fiber optic cable, therefore making it difficult for users. Furthermore, fiber optic cable requires extra care and effort once installed. Compared with optical fiber, coaxial cable enjoys the advantage of more convenient installment. In comparison between coaxial cable and twisted pair cable, twisted pair cables are much faster to install.

Application

Coaxial cable is used in cable TV connections, digital audio and also used by telephone companies. While twisted pair cable, the oldest and cheapest type of cable, remains in use throughout by telecommunications companies. As fiber has higher and faster data transfer than other types, it is usually used for professional networks such as data centers, enterprise network, commercial fields, medical treatment and even military field.

Conclusion

In sum, it’s inappropriate to judge which type is the best to use without considering application before selecting the cables. Hope you’re able to figure out the differences between these three cable types and find the type that’s just right for your current network setup. To get more information about types of cables, visit our website www.fs.com and contact us if you have any questions.

Introduction to Fiber Optic Cables

Currently, fiber optic cables are one of the most important and popular basic components in a wide variety of applications, such as computer networking, cable television, internet and so on. But have you ever wanted to learn what fiber optic cables are and how they work? Or do you wonder what advantages they have compared to conventional cables? If you are curious about answers to these questions, read on. In this article, you’ll learn a bit more about fiber optic cables.

What Fiber Optic Cables Are

 

Fiber optic cables, also known as optical fiber cables, are made up of a varying number of thin strands of optically pure glass fibers, from a few to several hundred. These fibers are arranged in bundles and surrounded by another glass layer.They are protected by a buffer and a jacket-the cable’s outer covering. Each cable is thinner than a human hair and it can carry much information over long distance at a very high speed by transmitting light signals through the thin cable.

At the very first, fiber optic cables are used for communication, and then they are used to network construction. Until now, fiber optic cables are applied in many other areas, such as medical treatment and commercial fields.

Types of Fiber Optic Cables

There are two primary types of fiber optic cables: single mode fiber (SMF) and multimode fiber (MMF).

 

The differences between the two fibers lay in their transmission medium and the ways of travelling. SMF generates light with the use of extremely thin glass strands and a laser while MMF uses LEDs. SMF is to go straight down the middle of the fiber while MMF is to bounce down the fiber at a shallow angle. The single mode fiber optic cable contains a thin core about 8μm to 10μm in diameter while multimode fiber has a core diameter about 50μm to 65μm, which means light beams can travel through the core in different modes. SMF offers a more direct route and allows the signal to travel longer. Therefore, the single mode fiber is used for long distance while the multimode fiber is used for relatively short distance. Generally, MMF is cheaper to make and install than SMF.

How Fiber Optic Cables Work

 

To understand how fiber optic cables work, imagine you are shinning a flashlight down a long, dark and straight hallway. The light will make it to the other end. But what if the hallway isn’t straight? How can the light go to the other end? Just imagine there are mirrors in the hallway, the light can reflect and bounce to the other end. The glass fiber core is where light travels, and cladding is an outer material that surrounds the core and reflects light back into the core. Due to the denser glass layers, the light signal travels about 30% slower than the speed of light. Therefore, in order to boost the signal, repeaters are sometimes required to convert optical signal to electrical signal, then process the electrical signal and retransmit the optical signal.

Advantages of Fiber Optic Cables

Compared with conventional copper cables, fiber optic cables show their unique advantages:

  • Greater bandwidth—Copper cables have very limited bandwidth from 10Gbps to 40Gbps because they are originally designed for voice transmission only. Fiber cables rate at 10 Gbps or 40 Gbps, even 200Gbps and 400Gdps are standard.
  • Faster speed—The core of fiber optic cables can transmit data by carrying light, making fiber optic cables carry signals at speeds that are nearly 31% slower than the speed of light, which are much faster than copper cables.
  • Longer distance—As the signal is carried through the cables, the signal in copper wire degrades faster than in optical fiber, suggesting that fiber optic cables can carry signals much farther than copper cables of the same bandwidth.
  • Less Power—As signals in fiber optic cables degrades slower than in copper cables, lower-power transmitters are required instead of high-voltage electrical transmitters.
  • Better Reliability—Typically, fiber is independent of the equipment and the termination points, which indicates that it is less influenced by other factors. In contrast, copper is easily influenced by weather conditions, utility time, etc. What’s more, fiber is less susceptible to electromagnetic interference than copper.
  • Thinner and Sturdier—Optical fibers can be drawn to smaller diameters than copper cables. Typically, copper cables can sustain about 25 pounds of pressure while fiber can sustain about 100-200 pounds of pressure, meaning fiber is less prone to breakage.

Conclusion

In sum, with its relatively low cost and less power, increased bandwidth, fast speed and long transmission distance, high reliability and quality, fiber has taken the place of copper in most aspects of network transmission. If you are looking for fiber optic cables and other communication hardware, FS.COM is absolutely your preferred choice. For more information, click here to find professional guidance.