November 5, 2021
Optical Transceiver
The optical transceiver module is the core device of optical communication, which completes the optical-to-electrical or electric-to-optical conversion of optical signals. It consists of two parts: the receiving part and the transmitting part. The receiving part realizes the conversion from optical to electric conversion, and the transmitting part realizes the conversion from electricity to optical.
Transmitting part:
The electrical signal with a certain code rate is processed by the internal drive chip and then drives the semiconductor laser (LD) or light-emitting diode (LED) to emit a modulated light signal of the corresponding rate. It has an automatic optical power control circuit (APC) inside to make the output The optical signal power remains stable.
Receiving part:
After the optical signal with a certain code rate is input into the module, it is converted into an electrical signal by the light detection diode, and the electrical signal with the corresponding code rate is output after the preamplifier. The output signal is generally PECL level. At the same time, an alarm signal will be output when the input optical power is less than a certain value.
The main parameters of the optical module
1. Transmission rate
Transmission rate refers to the number of bits transmitted per second, in Mb/s or Gb/s. Main speed: 100M, Gigabit, 2.5G, 4.25G and 10G.
2. Transmission distance
The transmission distance of the optical module is divided into three types: short-distance, medium-distance and long-distance. Generally speaking, 2km and below are short distances, 10-20km are medium distances, and 30km, 40km, 60km, 100km and above are long distances.
■The transmission distance of the optical module is limited, mainly because the optical signal will have a certain loss and dispersion when it is transmitted in the optical fiber.
Notice:
• Loss is the light energy loss due to the absorption, scattering, and leakage of the medium when light is transmitted in the optical fiber. This part of the energy is dissipated at a certain rate as the transmission distance increases.
• The generation of chromatic dispersion is mainly due to the unequal speed of electromagnetic waves of different wavelengths when propagating in the same medium, which causes the different wavelength components of the optical signal to reach the receiving end at different times due to the accumulation of transmission distance, resulting in pulse broadening and inability to distinguish Signal value.
• Therefore, users need to select the appropriate optical module according to their actual networking situation to meet different transmission distance requirements. Choose OLYCOM's SFP Module is your wise choice
SFP module, the full name is Small Form-factor Pluggable, namely: a small, hot-swappable optical transceiver module. The volume of the SFP module is half that of the GBIC module, and the number of ports can be more than doubled on the same panel. The other functions of the SFP module are basically the same as those of the GBIC. Some switch manufacturers call the SFP module a miniaturized GBIC (MINI-GBIC).
BIDI optical module
BiDi (Bidirectional) means single fiber bidirectional. Using WDM technology, different center wavelengths are used in the sending and receiving directions. Realize a fiber to transmit optical signals in both directions. Generally, the optical module has two ports, TX is the transmitting port and RX is the receiving port; and the optical module has only one port, which is filtered by the filter in the optical module, and simultaneously completes the transmission of 1310nm optical signals and the reception of 1550nm optical signals, Or vice versa. Therefore, the module must be used in pairs, and its biggest advantage is to save fiber resources.
Copper SFP, SFP package, SFP RJ45 port module, 100 meters can support a maximum transmission distance of 100m (RJ45, Category 5 twisted pair is the transmission medium).
SFP+ optical module: It is a new generation of 10 Gigabit optical module, which can meet the application of Fibre Channel 8.5G and Ethernet 10G according to ANSI T11 protocol
OLYCOM provides a variety of optical modules, the product models cover 155M/1.25G/2.5G/10G speed, multimode/single mode, single fiber/dual fiber, 550m/1Km/2Km/3Km/10Km/20Km/40Km/ 60Km/80Km/100Km/120Km. Meet customer's application requirements in various scenarios.
