Hello everyone, I am Rose. Today I will introduce the transceiver to you. A transceiver, sometimes known as an optical fiber transceiver, is a signal conversion device. This article will help you better understanding what is a transceiver.

Ⅰ.The meaning of Transceiver

A transceiver, sometimes known as an optical fiber transceiver, is a signal conversion device. The introduction of optical fiber transceivers enables the smooth transmission of data packets across the two networks by converting the electrical and optical signals of twisted-pair wires to each other. Simultaneously, it increases the network's transmission distance limit from 100 meters for copper lines to 100 kilometers (single Mode fiber).

Ⅱ. The classification of Transceiver

Fiber Transceiver

(1) Divided by rate

Single 10M, 100M, 100OM, 10G fiber optic transceivers, 10/100M adaptive, and 10/100/1000M adaptive fiber optic transceivers are all available. The physical layer is used by the majority of single 10M, 100M, and 1000M transceiver goods, and the transceiver products that work on this layer forward data bit by bit.

This forwarding method is suited for applications on fixed-rate lines because of its fast-forwarding speed and low delay. The 10/100M and 10/100/1000M fiber optic transceivers operate at the data link layer and employ a store-and-forward mechanism, with the forwarding mechanism reading the source and destination MAC addresses for each data packet received. After the CRC cyclic redundancy check is performed, transmit the data packet with the address and data payload.

The benefit of store-and-forward is that it prevents some mistake frames from propagating over the network and consuming important network resources. It can also prevent data packet loss due to network congestion at the same time. Store-and-forward can fail if the data channel is saturated. When the network is idle, the forwarded data is first placed in the transceiver's buffer and then forwarded. This not only decreases the likelihood of data conflicts, but also ensures data transmission reliability, making 10/100M and 10/100/1000M optical fiber transceivers appropriate for use on unfixed rate lines.

(2) Based on the technique of work

It can be separated into fiber optic transceivers that work at the physical layer and fiber optic transceivers that work at the data link layer, as previously stated.

(3) Based on the structure

There are two types of fiber optic transceivers: desktop (stand-alone) and rack-mounted fiber optic transceivers. The desktop optical fiber transceiver is designed for single-user applications (with built-in and external power supplies), such as meeting the uplink of a single switch in a corridor. Multiple users can be grouped together using rack-mounted optical fiber transceivers. The uplink of all switches in the community, for example, must be met by the community's central computer room. Racks make it easier to control and power all modular optical fiber transceivers from a single location. The fiber optic transceiver rack is a 16-slot device, which means it can hold up to 16 modular fiber optic transceivers.

(4) Fiber division

Multi-mode fiber optic transceivers and single-mode fiber optic transceivers are two types of fiber optic transceivers. The transmission distance of the transceiver varies due to the different optical fibers employed.A multi-mode transceiver's transmission distance is typically between 2 and 5 kilometers, but a single-mode transceiver's range is between 20 and 120 kilometers. It should be noted that the transmit power, receiving sensitivity, and wavelength of the fiber optic transceiver will all be different due to the difference in transmission distance. A 5km fiber optic transceiver, for example, has a transmit power of -20-14dB and a receiving sensitivity of -30dB when using a wavelength of 1310nm, but a 120km fiber optic transceiver has a transmit power of -3OdB and a receiving sensitivity of less than -36dB when using a wavelength of 1550nm.

(5) On the basis of the number of fibers

Single-fiber optical transceivers and dual-fiber optical transceivers are the two types. Single-fiber equipment, as the name implies, may save half of an optical fiber by receiving and sending data on a single optical fiber, making it ideal for regions where optical fiber resources are limited. The wavelengths utilized for short-distance transmission (O-60KM) and long-distance transmission (1490nm and 1550nm) in this type of product are typically 1310nm and 1550nm for short-distance transmission and 1490nm and 1550nm for long-distance transmission (60KM-120km). The products have matured and stabilized as the use of single-fiber optical transceivers has increased.

(6) Depending on the power source

Built-in power supplies and external power supplies are the two types. The external transformer power supply is generally utilized in civilian equipment, whereas the built-in switching power supply is carrier-grade. The former has the advantage of being able to support an ultra-wide power supply voltage, better-realizing voltage stabilization, filtering, and equipment power protection, and reducing external failure points caused by mechanical contact; the latter has the advantage of being small and simple to operate. Machines with 14 slots Low cost and centralized management. There are also AC 220V, 110V, 60V; DC -48V, 24V, and other voltages depending on the type of equipment.

(7) According to network administration

Network management type optical fiber transceiver and non-network management type optical fiber transceiver are two types of optical fiber transceiver. Most operators expect that as the network matures and becomes more operational and manageable, all of their equipment will be able to be handled remotely. Switches and routers, as well as fiber optic transceiver equipment, are gradually moving in this way. There are two types of fiber optic transceivers that can be networked: central office network administration and user terminal network management. The optical fiber transceivers that can be managed by the central office are mostly rack-mounted and use a master-slave management structure, which means that a master network management module can connect N slave network management modules in series and each slave network management module polls its sub-rack on a regular basis. The main network management module receives status information from all optical transceivers. On the one hand, the primary network management module must poll network management information on its own rack, and on the other, it must collect all data from the sub-rack, aggregate it, and send it to the network management server.

Ⅲ.The key technology of the Transceiver

1. Signal integrity

Phase-locked loop (PLL, phase-locked loop), CDR (clock and data recovery), 8B/10B codec, and other analog signals are used in the design of mixed signal modules. In a frequency divider, for example. Both analog and digital transmissions are susceptible to power synchronization noise, ground bounce, and signal crosstalk in a semiconductor. The non-ideal transmission line effect will make wiring more complex due to the larger data rate of the transceiver. Each layer's copper wires will create a "skin effect." Signal attenuation increases as high-frequency signals flow over the conductor's surface.

2. Jitter

Because jitter directly reflects the bit error rate of the transceiver, it is the most significant metric to measure the robustness of the transceiver. Jitter is affected by a variety of factors, including power and ground arrangement, calibration circuits, packaging features, and so on. The PLL generates a high-speed clock, which is the most crucial. The PLL is critical for clock and data recovery (CDR). The input reference clock drives the PLL, hence the reference clock input must meet stringent electrical and jitter requirements.

3. Equalization technology

Inter-symbol interference and various noise effects will undoubtedly occur as a result of the data carried in the channel. Its interference will be more noticeable at high speeds. An equalizer is incorporated into the transceiver system to overcome transmission interference and loss. The system characteristics can be rectified and compensated after equalization correction, and the influence of inter-symbol interference may be decreased, allowing the system to adapt to the channel's unpredictable changes.

4. Pre-emphasis technology

To overcome the signal loss problem at Gb-level rates, designers cannot simply boost the signal because this will increase power consumption and cause the eye diagram to collapse. Near the end of the arrangement, the intensity of the reflected energy shows a discontinuity. By stressing the first data symbol following any signal change, the pre-emphasis technology can perform pre-distortion processing on the transmitted signal, reducing front-end overshoot and trailing-edge tailing of the impulse response in the channel.

Ⅳ. The difference between Single Fiber and Dual Fiber Transceiver

Single-mode optical cables are used in single-fiber transceivers. Only one core is used in single-fiber transceivers. This core is attached to both ends. Both ends of the transceiver use separate optical wavelengths in order to transmit in a single core. There is a light signal.

The dual-fiber transceiver has two cores, one for transmission and the other for receiving. One end transmits while the other must be plugged into the receiving port, crossing the two ends.

There are two techniques to tell the difference between single-fiber and dual-fiber transceivers right now.

1. According to the number of fiber cores in the linked fiber jumper, the fiber optic transceiver is split into a single fiber transceiver and dual fiber transceiver when embedded with the optical module. The fiber jumper connected to the single-fiber transceiver (right picture) has a fiber core that is responsible for both transmitting and receiving data, whereas the fiber jumper connected to the dual-fiber transceiver (left picture) has a fiber core that is responsible for both transmitting and receiving data. Linearity consists of two cores, one of which is responsible for transmitting data and the other for receiving data.

    Dual Fiber Transceiver        Single Fiber Transceiver

2. When the optical transceiver does not have a built-in optical module, the optical module inserted must be used to determine if it is a single-fiber or dual-fiber transceiver. When a single-fiber bidirectional optical module is inserted into an optical fiber transceiver, that is, when the interface is simplex, the optical fiber transceiver is a single-fiber transceiver (pictured on the right); when a dual-fiber bidirectional optical module is inserted into an optical fiber transceiver, that is, when the interface is duplex, the optical fiber transceiver is a dual-fiber transceiver (pictured on the left) (left picture).

Dual Fiber Transceiver        Single Fiber Transceiver