Fiber Transceiver: How Much Do You Know about Hot-swappable

At present, almost most of the fiber transceivers are with "hot-swappable", or also called "hot-pluggable" functions (the following contents consistently use hot-swappable) in the optics market. However, there are few articles written for hot-swappable optical transceiver, because people generally consider it just a function that will help us save money or make our work more convenient and there is unnessary to know much about it. How about you? Are you really not interested in it or just because you don't have the resource to learn it? Here is an opportunity for you to learn much about the hot-swappable optical transceiver module, mainly the "hot-swappable" in this paper.

What's "Hot-swappable" Optical Transceiver?

Hot-swappable optical transceiver, is a device with a function that can support inserting or pulling out the module without shutting down the system or without significant interruption to the system and significant interruption to the operation of the system. This function can help us to avoid complete redesigns and cutdown the exorbitant costs associated with the practice, e.g. system updating. Now, optical transceivers, such as GBIC, SFP (Small Form Pluggable), SFP+ (Small Form Pluggable Plus), 40G QSFP etc. are all hot-swappable. The following figure shows Juniper Hot-pluggable 1000BASE-SX SFP - EX-SFP-1GE-SX:

Why "Hot-swappable" is So Important to Optical Transceiver?

As we know, optical transceiver module is an important part in optical transmission system. For each management or upgrade, we should power down the device until we finish the pluggable process, if we used a "non-hot-swappable" optical transceiver. However, because of the importance of telecommunications and data transmission systems, if power cuts carry on a long time, there will be a great loss. Additionally, the restart time of some operation systems is long which also leads a big loss. This is why it is so important to find devices that are hot-swappable. Nowadays, the hot-swappable technology is widely used in data communication and transmission industry and becomes more and more important.

Key Technologies of "Hot-swappable" Function

When people wanted to add the "hot-swappable" function to the optical transceiver modules, a cascade of problems must be solved to ensure the device work well. First, the we should guarantee the safety of the laser. As we know, laser is the most important and expensive part of an optical transceiver module. It is easy to be damaged and vulnerable to static electricity damage as it is a static sensitive component. In addition, we should also consider the surge current and system bus to avoid damaging the components of optical transceiver and causing interference to data transmission.

To solve these problems, people use some of the technologies to ensure safty and feasibility of hot-swappable optical transceiver modules. MSA (Multisource Agreement) defines using the TX_fault (Transmitter fault) to indicate whether the optical transceiver module works in good condition. When we inserted an optical transceiver, there is a initializing program. And the optical transceiver begin to test by itself after the power on. If the self test is approved, it will dirve the IC (integrated circuit) to offer the current to the laser, and then laser work. Otherwise, it will not offer current to the laser. In addition, adding a shutdown pin to the circuit that can close the LD (laser diode) when failure occurs is also a solution to ensure the saftey of laser.

Meanwhile, to reduce the surge current, we can use a specific sequence of power on. Moreover, we can also add a filter circuit as well as current limit switch to further reduce the surge current. Furthermore, in order to reduce the interference of hot-swappable module on the system bus, we usually employ connect pullup resistors and precharge technologies. These are also defined by MSA.

Ensure They are Hot-Swappable When You Buy Optical Transceiver

After reading the above contents, you will understand more about the "hot-swappable" function of optical transceiver and know how it is so important. This is why "hot-swappable" optical transceiver was so popular with users. We can never underestimate the power of optical transceiver modules that are hot-swappable. They can reduce expenditures for companies, especially when devices fail prematurely because they do not have to completely shut down the system to replace the device. When devices have more flexibility and functionality, companies save money and time. In a word, to ensure the optical transceiver module is hot-swappable when you decide to buy it.

Originally published at www.fiber-optic-transceiver-module.com.

What's the Difference Between Transceiver & Transponder?

In a fiber optic communication network, there are many equipment and facilities to support the normal operation of the system. Fiber optic transponder and fiber optic transceiver are the one of these devices. Literally, both of them are with a prefix "trans". It seems to imply that there is a similarity between them. Actually, they are not the same. So, what's the difference between them, something difference on principle or applications? Today, we are going to have a discussion on this topic.

First, in order to better understand the difference between a fiber optic transceiver and a fiber optic transponder, we need to define what each one does.

Fiber Optic Transceiver Most systems use a "transceiver" which includes both transmission and receiver in a single module. Its purpose, in broad terms, is to transmit and receive data. In fiber optic communication, the commonly used transceiver modules are hot-swappable I/O (input/output) devices which plug into module sockets. The transceiver acts to connect the electrical circuitry of the module with the optical or copper network. Devices such as routers or network interface cards provide one or more transceiver module slot (e.g GBIC, SFP, XFP), into which you can insert a transceiver module which is appropriate for that connection. The optical fiber, or wire, plugs into a connector on the transceiver module. There are multiple types of transceiver module available for use with different types of wire, fiber, different wavelengths within a fiber, and for communication over different distances. The most commonly used fiber optic transceivers include GBIC, SFP, SFP+, XFP, CFP, QSFP etc. They are widely used for different application, eg. 10G, 40G fiber optic transmission.

Fiber Optic Transponder "Transponder" includes a transmitter and a responder. It is a similar device with transceiver. In optical fiber communications, a transponder is the element that sends and receives the optical signal from a fiber. A transponder is typically characterized by its data rate and the maximum distance the signal can travel. According to its specific applications, it is also known as wavelength-converting transponder, WDM transponder or fiber to fiber media converter. Fiber optic Transponders extend network distance by converting wavelengths (1310 to 1550), amplifying optical power and can support the “Three Rs” to Retime, Regenerate and Reshape the optical signal. In general, there is an O-E-O (optical-electrical-optical) function with this device. Fiber optic transponders and optical multiplexers are usually present in the terminal multiplexer as an important component for WDM (Wavelength Division Multiplexing) system. In addition, in nowadays market, many transponders are designed as protocol and rate-transparent fiber media converters that support SFP, SFP+ and XFP transceivers with data rates up to 11.32 Gpbs, and with seamless integration of different fiber types by converting multi-mode fiber to single-mode fiber, and dual fiber to single-fiber.

Fiber Optic Transceiver vs Fiber Optic Transponder A transponder and transceiver are both functionally similar devices that convert a full-duplex electrical signal in a full-duplex optical signal. The difference between the two is that fiber transceivers interface electrically with the host system using a serial interface, whereas transponders use a parallel interface. So transponders are easier to handle lower-rate parallel signals, but are bulkier and consume more power than transceivers. In addition, transceivers are limited to providing an electrical-optical function only (not differentiating between serial or parallel electrical interfaces), whereas transponders convert an optical signal at one wavelength to an optical signal at another wavelength. As such, transponders can be considered as two transceivers placed back-to-back.

Author's Note I hope you can start down the path to fully understanding transceivers, transponders, and the difference between them, particularly in a networking, Ethernet, or fiber-optic communications setting after reading this article. Of cause, knowledge is endless, if you still want to get more information about transceiver and transponder, I suggest that you should find more references to read. If you just need to buy the related products, I will recommend Fiberstore.com to you as usual.

Article Source: Difference Between Transceiver & Transponder