Fiber optic transceivers can be classified into different categories based upon the nature of the fiber optic transceivers. The classification can be determined by a number of factors. The factors may range depending upon the type of transceiver and the application for which it’s intended. For example, the transfer distance may be a criterion for classifying transceivers, or the work level/rate points may be classification criteria for fiber optic transceivers. Here is an explanation of these criteria and some other criteria used to classify fiber optic transceivers.

According to the Optical Fiber to Points
Fiber optic transceivers can be divided into MMF (multi-mode fiber) transceiver and SMF (single-mode fiber) transceiver according to the optical fiber to points.

SMF Transceiver: transmission distance of 20-120 km
MMF Transceiver: distance 2 km to 5 km

Due to the use of different fiber transceiver can transmit distances are not the same, Multi-Mode transceivers typically at 2 km transmission distance between the 5 km, while the scope of the Single-Mode transceiver is covered from 20-120 km. It should be noted that due to different fiber transmission power of the transceiver itself, transmission distance, and the receiving sensitivity wavelength will be different. Such as 5 km of fiber optic transceivers transmit power is generally between -20 ~ -14db, receiver sensitivity -30db, 1310nm wavelength; and 120 km of fiber optic transceivers transmit power more in between -5 ~ 0dB, the receiver sensitivity is -38dB, using 1550nm wavelength.

According to the Required Optical Fiber
Fiber optic transceivers can be divided into simplex (single-fiber) transceiver and duplex (two-fiber or dual-fiber) transceiver according to the required optical fiber.

Simplex Transceiver: receiving the data sent in an optical fiber transmission.
Duplex Transceiver: receiving data transmitted on a fiber-optic transmission by definition.

Single-fiber optic equipment can save half of that achieved to receive and transmit data over a single optical fiber, optical fiber strain on the resources in place very applicable. Such products using wavelength division multiplexing technology, the use of multi-wavelength is 1310nm and 1550nm. But because there is no unified single fiber transceiver products to international standards, so different manufacturers products in the interconnection may be incompatibilities exist. In addition, as the use of wavelength division multiplexing, single fiber transceiver products ubiquitous signal attenuation characteristics of large. Fiber optic transceivers currently on the market are mostly dual-fiber products, such products are more mature and stable, but need more fiber.

According to the Working Level / Rate Categories

100M Ethernet optical transceiver: work at the physical layer
10 / 100M adaptive Ethernet optical transceiver: Work at the data link layer

According to the working level / rate points, can be divided into single-10M, 100M fiber optic transceivers, 10 / 100M adaptive 1000M fiber optic transceivers and fiber optic transceivers. One single 10M and 100M transceiver products operate at the physical layer, the work in this layer transceiver products are bit to forward data. The fast forward mode has forwarded advantage transparent rate, low latency aspects of the applied rate is fixed for the link, and because the process of these devices do not have a normal communication before auto-negotiation, and therefore compatible and stability better. The 10 / 100M fiber optic transceivers are working at the data link layer, using store and forward mechanism in which a layer of fiber optic transceivers, so that each data packet forwarding mechanism should read it received source MAC address, destination MAC address and data payload, and after the completion of CRC cyclic redundancy check before forwarding the packet out. Store and forward to the benefits of a frame can prevent some errors in the network communication, taking up valuable network resources, but also can very well prevent network congestion due to packet loss, when the data store and forward link saturation can not be forwarded data first on the transceiver’s cache, and then forwards the network is idle while waiting. This not only reduces the possibility of data conflicts and ensure the reliability of data transmission, so 10 / 100M fiber optic transceiver is adapted to the work rate is not fixed link. 1000M fiber optic transceivers can actually need to work at the physical layer or data link layer, on the market two 1000M fiber optic transceivers are available.

According to the structures

Desktop Transceivers: stand-alone CPE
Rack (modular) fiber optic transceivers: installed on sixteen-slot chassis with centralized power supply

According to the structure points, can be divided into the desktop (standalone) rack-mounted fiber optic transceivers and fiber optic transceivers. Desktop fiber optic transceiver is adapted to individual users, such as the corridor in a single switch on the Union met. Rack (modular) fiber optic transceivers for multi-user aggregation, such as the central office district on the Union must meet all switches within the cell, use a rack to facilitate unified management and unified power to all modules fiber optic transceivers , currently more than 16 slot rack products, namely a rack insert up to 16 modular fiber optic transceivers.

According to Management

Unmanaged Ethernet Transceiver: Plug and Play, DIP switch setting mode by electrical interface hardware
Managed Ethernet transceiver: support carrier-grade network management

By Webmaster points, can be divided into managed and unmanaged fiber optic transceiver fiber optic transceivers. As the network toward operable and manageable direction, most operators want their network to all devices are able to do remote network management degree, fiber optic transceivers and switches, routers, like progressive development in this direction. For Managed optical transceiver can also be broken down into the central office and customer premises Managed Managed. Managed central office optical transceiver products are mainly rack, multi-use master-slave management structure, namely a main network management module can be connected in series from the N network modules, each sub-frame in which it periodically polls from network management module All fiber optic transceiver status information submitted to the main network management module. On the one hand the need to poll the primary network management network management information module on the rack himself, on the other hand need to collect all the information from the sub-frame, and then summarized and presented to the network server.

Client network can be divided into three ways: The first is to run a specific agreement between the central office and customer premises equipment, protocols, the client is responsible for sending status information to the central office, the central office equipment by the CPU to handle these state information and submit it to the NMS server; the second is the central office optical transceiver can detect the optical power of the optical port on, so when there is a problem on the optical path can be judged according to the light power is an issue on the fiber or CPE failure ; third is on the client’s installation of fiber optic transceivers host CPU, so one can monitor the network management system to a working state CPE, in addition can also achieve remote configuration and remote restart. In these three client network management mode, strictly speaking, only the first two on the CPE remote monitoring, and the third is the real remote network management. However, due to the third way in the client adds CPU, thus increasing the cost of CPE, so before the price advantage will be some two ways. Most vendors of network management systems are based on SNMP network protocol development and support, including a variety of management Web, Telnet, CLI and so on. Manage more content, including configuration mode fiber optic transceivers, fiber optic transceiver module monitor type, work status, chassis temperature, power supply, the output voltage and output optical power, and so on. As operators of the demand for more and more network equipment, fiber optic transceivers believe will become more practical and intelligent network management.

According to the Power Supply

Built-in power supply fiber optic transceivers: Built-in switching power supply for telecom
External power supply fiber optic transceivers: external transformer power for civilian use on multiple devices

Press the power points, can be divided into two kinds of built-in power and external power. Where the built-in switching power supply for telecom-grade power supply and external transformer power for civilian use on multiple devices. The former has the advantage of wide supply voltage can support better achieve regulation, filtering and power protection equipment, reducing external contact caused by a mechanical failure points; the latter has the advantage of compact and inexpensive equipment and price.

According to the Work Ways
According to the work ways, fiber optic transceivers can be divided into full-duplex mode and half-duplex mode.

Full-duplex mode (full duplex) means that when data is sent and received diversion, respectively, by the time two different transmission lines to carry communications both transmit and receive operations can be carried out at the same time, this is a full-duplex transmission mode system . In full duplex mode, each end of the communications system are set up the transmitter and receiver, so that the control data can be transmitted simultaneously in both directions. Full-duplex mode without switching direction, and therefore, there is no switching time delay generated by the operation.

Half-duplex mode (half duplex) refers to the use of the same transmission line as both a reception also for sending, although the data can be transmitted in both directions, but the two sides can not both send and receive data communications, this is a half-duplex transmission mode system. When using half-duplex mode, each end of the communication system transmitter and receiver, through the transmit / receive switch is transferred to the communication line, switching directions, therefore, will produce a time delay.

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