What Is an Optical Transceiver?

Optical fiber transceiver is an Ethernet transmission media conversion unit that exchanges short-distance twisted-pair electrical signals with long-distance optical signals. It is also called a fiber converter in many places. The product is generally applied in the actual network environment where the Ethernet cable cannot cover, and fiber must be used to extend the transmission distance, and is usually positioned in the access layer application of the broadband metropolitan area network; Helping to connect the last mile of fiber optic lines to metropolitan area networks and outer networks also played a huge role.

Fiber Transceiver

Foreign and domestic production

Mention

due to

Ring backbone network

The ring-shaped backbone network uses the SPANNING TREE feature to build a backbone within the metropolitan area. This structure can be transformed into a mesh structure, which is suitable for

1.Power light is off

electricity failure

2. The following faults must occur when the LOS light is off:

(A) The fiber optic cable from the computer room to the user's end has been broken.

(B) SC pigtail and

Essentially

In the design of the Ethernet optical fiber transceiver, the choice of components is very important, which determines the performance, life and cost of the product. Optoelectronic medium

The conversion chip (OEMC) is the core of the entire transceiver. Selecting a media conversion chip is the first step in the design of an Ethernet optical transceiver, and it is also very important.

An important step. Its choice directly affects and determines the choice of other components.

The main performance indicators of the photoelectric medium conversion chip are:

1. Network Management Function

Network management is a guarantee of network reliability and a way to improve network efficiency. Functions such as operation, management, and maintenance of network management can be greatly enhanced.

Greatly increase the available time of the network, improve network utilization, network performance, service quality, security and economic benefits. But the development has a network management function

The human and material resources required for a capable Ethernet fiber optic transceiver far exceed that of similar products without network management, which are mainly manifested in:

(1) Hardware investment. The realization of the Ethernet fiber transceiver network management function requires the network management information processing unit to be configured on the transceiver circuit board to process the network.

Management information, the unit uses the management interface of the media conversion chip to obtain management information. Management information shares common data channel with common data on the network

. The Ethernet optical transceiver with network management function has more types and quantities of components than similar products without network management. Correspondingly, the wiring is complicated and the development

The cycle is long. Fiberhome Networks has long been committed to the development of fiber optic transceiver products. In order to optimize the product design, make the product more stable and enhanced.

Product functions, independently developed fiber transceiver media conversion chip, making the product more integrated, effectively reducing the

The same factors of instability caused by work. The newly developed chip has many practical functions such as online testing of fiber line quality, fault location, and ACL.

Strong functions can not only effectively protect user investment, but also greatly reduce user maintenance costs.

(2) Software investment. In addition to hardware wiring, software programming is more important for the research and development of Ethernet optical transceivers with network management functions. network management

Software development workload is large, including graphical user interface part, network management module embedded system part, transceiver management board network management information

Processing unit section. The embedded system of the network management module is particularly complicated, and the threshold for research and development is high. Embedded operating systems are required, such as

VxWorks, linux, etc. Need to complete SNMP agent, telnet, web and other complex software work.

(3) Commissioning work. The debugging work of the Ethernet optical transceiver with network management function includes two parts: software debugging and hardware debugging. While debugging

During the process, any factors in circuit board wiring, component performance, component welding, PCB board quality, environmental conditions, and software programming will

Affects the performance of Ethernet fiber optic transceivers. The commissioning personnel must have comprehensive quality, and consider all factors of transceiver failure.

(4) Staff input. The design of a common Ethernet fiber optic transceiver requires only one hardware engineer. Ethernet with network management function

In addition to the design of the optical fiber transceiver, in addition to the hardware engineer to complete the circuit board wiring, but also the software engineer to complete the network management

Process, and requires close cooperation between software and hardware designers.

2. compatibility

OEMC should support IEEE802, CISCO ISL and other common network communication standards to ensure good compatibility of Ethernet fiber optic transceivers.

3 Environmental requirements

a. Input and output voltage. The operating voltage of OEMC is mostly 5 volts or 3.3 volts, but another important device on the Ethernet optical transceiver-

The working voltage of the optical transceiver module is mostly 5 volts. If the two operating voltages are not the same, it will increase the complexity of PCB board wiring.

b. Operating temperature. When choosing the operating temperature of the ODEC, developers need to start from the most unfavorable conditions and leave room for it, such as the summer

The high temperature reaches 40 ° C, and the inside of the Ethernet fiber optic transceiver chassis is heated by various components, especially the OEMC. Therefore, Ethernet fiber transceivers

The upper limit of the working temperature should not be lower than 50 .

Classification of fiber optic transceivers

With the diversified development of optical fiber transceiver products, their classification methods are also different, but there is a certain correlation between the various classification methods.

Divide by rate

Can be divided into single 10M, 100M, 1000M, 10G optical transceivers, 10 / 100M adaptive, 10/100 / 1000M adaptive optical transceivers.

Most of the single 10M, 100M and 1000M transceiver products work at the physical layer. The transceiver products working at this layer forward data bit by bit.

This forwarding method has the advantages of fast forwarding speed and low delay, and is suitable for being applied to a link with a fixed rate. The 10 / 100M and 10/100 / 1000M fiber optic transceivers work at the data link layer and use a store-and-forward mechanism. In this way, the forwarding mechanism must read its source MAC address and destination MAC address for each received packet. Address and data payload, and the data packet is not forwarded until the CRC cyclic redundancy check is completed.

The advantage of store and forward can prevent some error frames from spreading on the network, occupying valuable network resources, and it can also prevent data packet loss due to network congestion. When the data link is saturated, store and forward The forwarded data is first placed in the buffer of the transceiver, and then forwarded when the network is idle. This not only reduces the possibility of data conflicts, but also ensures the reliability of data transmission. Therefore, 10 / 100M, 10/100 / 1000M fiber optic transceivers are suitable for working on links with variable speed.

Divided by work method

As described above, it can be divided into a fiber optic transceiver working at the physical layer and a fiber optic transceiver working at the data link layer.

Divided by structure

Can be divided into desktop (stand-alone) optical transceivers and rack-mounted optical transceivers. Desktop optical transceivers are suitable for single users (and built-in power transceivers and external power transceivers), such as to meet the uplink of a single switch in the corridor. The rack-type optical fiber transceiver is suitable for the aggregation of multiple users. For example, the central computer room of the cell must meet the uplink of all the switches in the cell. The use of a rack facilitates the unified management and unified power supply of all modular optical fiber transceivers. The fiber optic transceiver rack is a 16-slot product, that is, a maximum of 16 modular fiber optic transceivers can be inserted into a rack.

Divided by fiber

Can be divided into multi-mode fiber optic transceivers and single-mode fiber optic transceivers. Due to different optical fibers, the distance that the transceiver can transmit is different

Multi-mode transceivers generally have a transmission distance between 2 km and 5 km, while single-mode transceivers can cover a range from 20 km to 120 km.

It should be pointed out that due to different transmission distances, the optical transceiver's own transmit power, receiving sensitivity, and wavelength used will also be different. As 5

The transmission power of a kilometer fiber optic transceiver is generally between -20 and -14db, the receiving sensitivity is -30db, and a wavelength of 1310nm is used; and 120km

The transmission power of the optical fiber transceiver is mostly between -3 and 0dB, the receiving sensitivity is less than -36dB, and a wavelength of 1550nm is used.

Divided by the number of fibers

Can be divided into single fiber optic transceivers and dual fiber optic transceivers. As the name implies, single-fiber equipment can save half the fiber,

Receiving and sending data on the fiber is very suitable for places where fiber resources are tight. This type of product uses wavelength division multiplexing technology.

The wavelength is mostly 1310nm and 1550nm for short distance transmission (0-60KM) and 1490nm and 1550nm for long distance transmission (60KM-120km). With the increasing use of single fiber optic transceivers, the product has matured and stabilized.

Divided by power

Can be divided into two kinds of built-in power and external power. The built-in switching power supply is a carrier-grade power supply, and the external transformer power supply is mostly used in civilians.

With the device. The advantage of the former is that it can support ultra-wide power supply voltage, better achieve voltage stabilization, filtering and equipment power protection, and reduce mechanical

External failure points caused by contact; the latter has the advantages of small size, easy to use 14-slot racks for centralized management, and low price.

In addition, according to the type of equipment supply voltage, there are AC 220V, 110V, 60V; DC -48V, 24V and so on.

Divided by network management

Can be divided into network-managed optical transceivers and non-managed optical transceivers. As the network moves towards operability and management, most

Operators hope that all devices in their network can achieve remote network management. Fiber optic transceiver products are the same as switches and routers.

Also gradually develop in this direction. For network-manageable optical transceivers, it can also be subdivided into local-side network-manageable and user-side network-manageable. Central network management

Fiber optic transceivers are mainly rack-type products, mostly adopting a master-slave management structure, that is, one master network management module can connect N slave network management modules in series.

Each slave network management module periodically polls the status information of all fiber optic transceivers on its subrack and submits it to the master network management module. Main network management module

You need to poll the network management information on your own rack. On the other hand, you need to collect all the information on the slave racks, and then aggregate and submit it to the network management service.

Device.