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Category: Network Media Coversion

Application Schemes of WDM Transponder (O-E-O)

Application Schemes of WDM Transponder (O-E-O)

The WDM (Wavelength Division Multiplexing) transponders, also called O-E-O (optical-electrical-optical) wavelength converters are widely deployed in a variety of networks and applications nowadays, especially the in WDM networking system. In the previous article “What’s the Difference Between Transceiver & Transponder?“, we have learn that the basic concept about the transponder and make clear the difference with transceiver. Today, I am going to talk something about the applications of WDM transponders through several practical cases.

Reviewing the Concept of WDM Transponder

WDM transponder is an optical-electrical-optical (O-E-O) wavelength converters which is designed to performs an O-E-O operation to convert wavelengths of light. Figure 1 shows bidirectional transponder operation (the transponder is located between a client device and a DWDM system). From left to right, the transponder receives an optical bit stream operating at one particular wavelength (1310 nm). And then it converts the operating wavelength of the incoming bitstream to an ITU-compliant wavelength and transmits its output into a DWDM system. On the receive side (right to left), the process is reversed. The transponder receives an ITU-compliant bit stream and converts the signals back to the wavelength used by the client device.


Figure 1. WDM Transponder Working Principle

Application Schemes of WDM Transponder

As the above mentioned, the WDM transponder is widely used in many networks and applications. Here are three classical application schemes of the WDM transponders.

1. Convert Multimode to Single-Mode Fiber

As we know, multimode fiber (MMF) is used for short-distance transmission while the single-mode fiber (SMF) is used for the longer-distance transmission. Mode conversion is required in the network since the network distance requires to exceed the limit of MMF or in the case that equipment is designed with multi-mode port but connectivity is required to single-mode equipment. As the Figure 2 shown, two switches are connected by the WDM transponders which convert the MMF to SMF, enabling the network connectivity across the distance between the switches.

Multimode to Single-Mode Fiber Conversion

Figure 2. Multimode to Single-Mode Fiber Conversion

In addition, the WDM transponder can also be used between a 10G SFP+ DAC (Direct Attach Copper) cable to a SMF. As the Figure 3 shown, a 10m 10G SFP+ DAC cable is used to connect the 10G switch port to the transponder (in the left location); A pair of multimode SFP+ transceivers provide the connectivity between the transponder and the 10G switches (in the right location). This solution is ideal for the application which requires to connect switches exceeds the distance limitation (10 meter) of 10G DAC cable.

10G DAC to Single-Mode Fiber to Multi-mode Fiber Conversion

Figure 3. 10G DAC to Single-Mode Fiber to Multi-mode Fiber Conversion

2. Covert Dual Fiber to Single Fiber

Dual fiber transmission and single fiber transmission are two transmission modes applied in the network. Depending on the type of equipment and the fiber installed facility, dual fiber to single fiber conversion is required sometimes. Here are two situations:

a. Dual Fiber to Single Fiber Conversion

In this case, two dual fiber switches are connected with a single fiber via two transponders. The single fiber is single-mode fiber (1310/1550 nm) and operates with BiDi (bi-directional) wavelengths. See Figure 4.

Dual Fiber to Single Fiber Conversion

Figure 4. Dual Fiber to Single Fiber Conversion

b. Double Fiber Capacity With Dual Fiber to Single Fiber Conversion

Dual fiber uses the same wavelength over two different strands of fiber—one strand as Transmit (Tx) and the other as Receiver (Rx). See Figure 5.

 Traditional Dual Fiber Connection

Figure 5. Traditional Dual Fiber Connection

By converting the dual fiber to single fiber, the network can double the capacity of the exisiting infrastructure, as the Figure 6 and 7 shown.

Double Fiber Capacity With Dual Fiber to Single Fiber Conversion (two links)

Figure 6. Double Fiber Capacity With Dual Fiber to Single Fiber Conversion (two links)

In this application, two other switches are added to each link. The transponder doubles the capacity of the dual fiber link by converting each strand from a dual fiber link to a BiDi single fiber link.

Double Fiber Capacity With Dual Fiber to Single Fiber Conversion (single link)

Figure 7. Double Fiber Capacity With Dual Fiber to Single Fiber Conversion (single link)

In this case, the transponder doubles the capacity of two dual fiber links by converting each strand of the dual fiber to two BiDi single fiber link, providing redundancy protection between the two switches.

3. Wavelengths Conversion

Wavelengths conversion is the most common application of a WDM transponder. Fiber network equipment with fixed fiber interfaces (ST, SC, LC FC, etc.) operating over legacy wavelengths (850 nm, 1310 nm, 1550 nm) must be converted to CWDM (Coarse Wavelength Division Multiplexing) or DWDM (Dense Wavelength Division Multiplexing) wavelengths via a WDM transponder which is to automatically receives, amplifies, and then re-transmits a signal on a different wavelength without altering the data/signal content. As the Figure 8 shown, a 10G switch with signal output at 1310 nm is required to link to a CWDM Mux/DeMux channel port (1610nm wavelength). A transponder configured with a standard SMF SFP+ and a 1610nm CWDM SFP+ is used between the switches and CWDM Mux/DeMux, achieving the wavelength conversion.

Wavelenth Conversion in CWDM System

Figure 8. Wavelenth Conversion in CWDM System

Tips on Using WDM Transponders

After leaning the above contents, we know that WDM transponders can be used in mode conversion, dual to single fiber conversion as well as the wavelength conversion. When using the WDM transponders, you should note the following point:

  • It is not necessary to use the transponder for single wavelength transmission;
  • The number of transponders used in the network depends on your actual network plan;
  • You should choose the corresponding transceivers and linecard to configure the transponder according to your requirement.
Introduction to Fiber Optic Transmitter

Introduction to Fiber Optic Transmitter

Fibre optic transmitter choices
Businesses of various aspects to any fiber optic transmitter. For just about any application, the various specifications need to be examined to make sure that the particular fibre optic transmitter will meet what’s needed.
One of the major aspects to any fiber optic transmitter, is its power level. There’s no question that the fiber optic transmitter must have a sufficiently high level of sunshine output for the light to be transmitted across the fiber optic cable towards the far end. Some fibre optic cable lengths many simply be several metres or many metres long, whereas others may extend for many kilometres. In the case of the long lengths, the strength of the fiber optic transmitter is of great importance.
The kind of light produced can also be important. Light could be split up into two classes, namely coherent and incoherent light. Essentially, coherent light includes a single frequency, whereas incoherent light contains a wide selection of light packets all containing different frequencies, i.e. there is no single frequency present. Although some emitters may appear to emit just one colour, they can be incoherent since the light output is centred around a given frequency or wavelength.
The regularity or wavelength from the light may also be important. Often fibre optic systems will operate around a given wavelength. Often the wavelength of operation is given.
It is also necessary to consider the rate where the transmitter can be modulated because this affects the data rate for that overall transmission. Sometimes low rate systems may only need to carry data for a price of some Mbps, whereas main telecommunications links have to transmit data at many Gbps.

How do Fiber Optic Transmitters Work?
Fiber optic transmitters contain an interface circuit, a source drive circuit, as well as an optical source. The interface circuit receives electrical signals. The source drive circuit converts these to optical signals and triggers the LED or laser diode that then sends the sunshine signals to the fiber optic cable, where they visit their destination.(see Figure 1.)

Fiber optic Transmitters working process

Figure 1. Optical Transmitter working process

Light Sources 
There are two main types of fibre optic transmitter that are in use today. Both of them are based around semiconductor technology:
Light emitting diodes (LEDs)
LEDs are utilized mainly for short-to-moderate transmission distances because they have relatively large emitting areas. Shiny things cost less than laser diodes, but possess a limited bandwidth.
Laser diodes
Laser diodes can couple many times more power to optical fiber than LEDs. They are more expensive, but they are required for applications that must transmit signals over long distances.
We may see the comparison in Figure 2.

chief charactristics of LED and LASER DIODE

Figure 2. Chief Charactristics of LED and LASER DIODE

Cable Types
Fiber optic transmitters are designed for use with single mode and/or multi-mode cable.(see Figure 3.)

mmf&smfFigure 3. SMF&MMF

Single-mode fibers (SMF) have small cores and therefore are used withlaser sources for top speed, long-distance links. They transmit infrared (IR) laser light at wavelength from 1,300 to at least one,550 nm.
Multimode fibers (MMF) have larger cores and are used mainly with LED sources for lower speed, shorter distance links. The typical transmission speeds and distance limits are 100 Mbit/s for approximately 2km, 1Gbit/s to 220-550m, and 10Gbit/s to 300m.

Performance and Input Specifications
When selecting fiber optic transmitters, you will find five main performance specifications to think about: data rate, transmitter rise time, wavelength, spectral width, and maximum optical output power. Inputs include TTL, ECL, CMOS, RF, and video.

About Fiberstroe’ s fiber optic transmitters
Fiberstore’s Optical transmitters are special optical transmitting equipments in HFC broadband transmitting network. The product which use direct optical intension, low RF-signal input level, excellent airproof and fast-heating capability, make it possible work at any kind of bad environment. It can transmit analog TV signal, digital TV signal and INTERNET data signal in 860MHz frequency.(Figure 4.)


  • 1310 broadcast and narrowcast applications
  • CATV forward path
  • RF over fiber

«Figure 4. Fiberstore’s Optical transmitter

Difference between Unmanaged media converter and Managed media converter

Difference between Unmanaged media converter and Managed media converter

Unmanaged vs. Managed
An unmanaged media converter simply allows devices to communicate, and does not provide the same level of monitoring, fault detection and configuration as equivalent managed media converters. Connect the devices to the unmanaged media converter and they usually communicate automatically. Unmanaged media converters are simple to use and install. For most unmanaged converters, minimal configuration is required.

A managed media converter is typically more costly than an unmanaged media converter.However, a managed converter provides additional network monitoring, fault detection and remote configuration functionality not available with an unmanaged media converter.

The advantages of Fiberstore’s Managed Media Converters
Fiberstore’s Managed Media Converters extended copper to fiber, multimode to multimode and multimode to single mode fiber with extensive security, network integration and ease of use features that are not available in similar products by other manufacturers.

Fiberstore’s Managed Media Converters support all authentication, authorization and accounting (AAA) security services used in corporate networks, including TACACS+, RADIUS, LDAP, Kerberos, NIS and RSA. To further protect ID’s and passwords from someone ‘snooping’ on the network, our Managed Media Converters provide secure management sessions by supporting SSH, SNMPv3, Telnet and HTTPS. These types of features are used when managing your corporate firewalls, switches and routers. It should be expected that they are also available in your Managed Media Converter.

You will also appreciate how easy the Fiberstore Managed Media Converters are to set up with an intuitive Web Manager GUI and multiple methods of access. And, with support for IPv6, Fiberstore Media Converters provide organizations with investment protection to meet this rapidly growing standard.

Image of Fiberstore’s Managed Media Converters

Managed media converterYou could find another related products in Fiberstore

  • 10/100Base Ethernet Fiber Media Converters
  •  1000Base Gigabit Fiber Media Converter
  •  SFP Fiber Media Converter
  •  POE media Converter
  • Options in singlemode dual fiber,multimode dual fiber and singlemode single fiber
  • Media Converters Chassis, like 14 slot media converter chassis and 16 slot media converter chassis, used to manage the various media converters.
SFP Media Converters Those Support Fast Ethernet Standards

SFP Media Converters Those Support Fast Ethernet Standards

SFP Media Converter is a Fiber to Ethernet Media Converter with Fast Ethernet ports, dual-rate Fast/Gigabit Ethernet ports, or Gigabit Ethernet ports. The ports allow for flexible network configurations using SFP transceivers. And the Fast Ethernet SFP Media Converter uses Fast Ethernet SFPs.

FiberStore Fast Ethernet  SFP Media Converter

According to the types of Fast Ethernet SFPs, there are corresponding kinds of Fast Ethernet SFP Media Converters. We should know the Fast Ethernet standards to understand this device.

Fast Ethernet is a collective term for a number of Ethernet standards that carry traffic at the nominal rate of 100Mbps, against the original Ethernet speed of 10Mbps. There are several Fast Ethernet standards including 100Base-T, 100Base-TX, 100Base-FX, 100Base-SX, 100Base-BX, etc.. Obviously, the “100” means 100Mbps rate.

100Base-T is an initial Fast Ethernet standard for twisted pair cables. The segment length for a 100Base-T cable is limited to 100m. 100Base-TX is the predominant form of Fast Ethernet, and runs over two wire-pairs inside a CAT5 or above cable. Since a typical CAT5 cable contains 4 pairs, it can support two 100Base-TX links with a wiring adaptor. Of the Fast Ethernet standards, 100Base-TX is by far the most widespread and is supported by the vast majority of Ethernet hardware currently produced.

100Base-FX is a version of Fast Ethernet over optical fiber. It uses a 1300nm NIR light wavelength transmitted via two strands of optical fiber, one for receive(RX) and the other for transmit(TX). 100Base-FX should use SC, ST, LC, MTRJ or MIC connectors with SC being the preferred option. However, it is not compatible with 10Base-FL, the 10Mbps version over optical fiber. A 100Base-FX SFP operates on ordinary MMF (multimode fiber) link spans up to 2km.

100Base-SX is another version of Fast Ethernet over optical fiber. It uses two strands of multimode optical fiber for RX and TX. It is a lower cost alternative to using 100Base-FX, because it uses short wavelength optics which are significantly less expensive than the long wavelength optics used in 100Base-FX. 100Base-SX can operate at distances up to 550m. It uses the same wavelength as 10Base-FL. Unlike 100Base-FX, this allows 100Base-SX to be backwards compatible with 10Base-FL. Because of the shorter wavelength used (850nm) and the shorter distance it can support, 100Base-SX uses less expensive optical components (LEDs instead of lasers) which make it an attractive option for those upgrading from 10Base-FL and those who do not require long distances.

100Base-BX is a version of Fast Ethernet over a single strand of optical fiber, while 100Base-FX uses a pair of fibers. Single-mode fiber is used along with a special multiplexer which splits the signal into TX and RX wavelengths. The two wavelengths used for TX and RX are 1310/1550nm. The terminals on each side of the fiber are not equal, as the one transmitting downstream uses the 1550nm wavelength, and the one transmitting upstream uses the 1310nm wavelength. Its transfer distances can be 10, 20 or 40 km. A 100Base-BX SFP operates on ordinary SMF (single mode fiber) single-strand link spans up to 10km.

Contraposing to these different standards, Fast Ethernet SFP Media Converters are designed with different SFP ports to support the 100Base-T SFP, 100Base-FX SFP, 100Base-SX SFP, 100Base-BX SFP and even 100Base-FX to 100Base-TX SFP transceiver which is used in the converter with two SFP ports (100Base-FX and 100Base-TX).

FiberStore supplies not only 100Base SFP Media Converters for Fast Ethernet, but also 1000Base SFP Media Converters for Gigabit Ethernet. These SFP Media Converters extend copper to fiber, multimode to multimode and multimode to single mode fiber by working with the SFP module. An extensive range of SFP Media Converters are in stock to meet every fiber conversion need.

Here are some features of FiberStore’s Fast Ethernet SFP Media Converters

1. Extend Fast Ethernet network distances up to 120km

2. Support multimode and single mode fiber

3. Support SC, LC and ST fiber connectors

4. Special functions like Link Pass-Through, Far-End Fault, Auto-MDIX and Loopback

Tips: Link Pass Through is a troubleshooting feature that allows the media converter to monitor both the fiber and copper RX ports for loss of signal. Auto-MDIX is a function automatically detects and configures the twisted pair port on the converter to the correct MDI-X configuration.

Protocol Converter Is The Key Component In Communication

Protocol Converter Is The Key Component In Communication

The Protocol Converter, a device converts one protocol into other protocol, is ideal for situations where data from monitored equipment is incompatible with the protocols used by the building management system (BMS) or network management system (NMS), such as in cases where legacy monitoring systems are present. The ability of the protocol converter to accept up to 1,024 inputs over 32 modules means flexible integration with multiple alarm and management systems using one simple device. Protocol converters are widely used in process or industrial automation, building automation, substation automation, automatic meter reading and vehicle automation applications.

Protocol converters are normally used with switches, PCIe network cards and fiber media converters, CWDM and DWDM equipment, PDH multiplexers etc. Protocol converter series may put into action the actual transformation in between single E1 protocol port as well as protocol ports of V.35, V.24, RS232 or Ethernet within the tranny system; it may be thoroughly utilized in numerous being able to access problems with regard to providers as well as commercial clients, for example DDN, ATM, as well as for that transformation in between router and E1 port, or even the actual occasion exactly where Ethernet tend to be interconnected from divided internet websites through SDH or even additional tranny gear.

1. Protocol converter can offer local, remote loop-back functions, commanded remote device loop-back as well as pseudo-random code testing perform; loop-back perform may be used without influence on normal network data conversation and can not really lead to the actual meltdown of network;

2. E1 port may support 120ohm/75 ohm opposition concurrently;

3. V.24 port may assistance a rate of 64K or 128K (optional), and may carry out tranny from any kind of specific time-slot within E1 port; also it can function under DTE and DCE modes;

4. V.35 user port may support N*64K (N=1~32) adaptive rate, and may assistance inner, exterior and slave clock modes, in order to end up being designed in order to numerous programs; also it can function under DTE and DCE modes;

5. RS232 port may assistance the actual a good adaptive rate lower than 115.2K;

6. Ethernet port may assistance N*64K (N=1~32) adjustable rate, and may assistance four channels of Switched Ethernet ports and may end up being channel-isolated; Ethernet mode may assistance 10M/100M semi-duplex as well as 10/100M full-duplex modes as well as adaptive mode (optional), as well as assistance VLAN protocol;

7. Ethernet protocol convertor may identify the actual delivering as well as getting information caution associated with E1 port instantly, as well as switch off Ethernet function instantly.

How To Choose A Converter

There are basically two types of protocol converter which are listed below.

1. Software Protocol Converters
2. Hardware Protocol Converters

Some of the most popular industrial automation protocols are DF-1, CAN (Controller Area Network), RS232 Ethernet Converter, RS422 Ethernet Converter, ControlNet, DeviceNet, HostLink Protocol, Profibus, Modbus, Honeywell SDS, HART Protocol, EtherNet/IP etc. And some Industrial control system protocols like MTConnect, OPC, OPC UA. Select the converter that best matches your application and communication setup, keeping in mind three key features:

Number of connections—some converters support single connections, while others provide as many as 32 multiple connections with multiple serial ports.

Baud rate—we have seen converters with baud rates as high as 921kbaud. Converters with lower baud rates are less expensive, but their performance is slower.

Connectivity protocol—the converter must support the protocol used by your network, either TTL serial, RS-232, RS-422, or RS-485.

Consider the number of connections, baud rate and connectivity protocol, you can finally buy a protocol converter meet your applications.