The optical module consists of optoelectronic devices, functional circuits, and optical interfaces. The optoelectronic devices include both transmitting and receiving parts, which are used for optical signal transmission and are usually inserted into the optical module slots of switches, routers, or network interface cards.
The transmission distance of optical modules is divided into three categories: short, medium, and long. Generally, distances of 2km or less are considered short, 10-20km are medium, and 30km or more are long.
Currently, the central wavelengths of optical modules are mainly in three categories: 850nm, 1310nm, and 1550nm. The 850nm band is mostly used for short-distance transmission, while the 1310nm and 1550nm bands are mostly used for long-distance transmission.
There are many types of optical modules, which can be divided by package into 1*9, GBIC, SFF, SFP, XFP, SFP+, X2, XENPARK, QSFP28, QSFP+; by speed into 10G, 25G, 40G, 100G, etc.; by wavelength into conventional wavelength, CWDM, DWDM, etc.; by mode into single-mode fiber (yellow), multi-mode fiber (orange); and by usage into hot-swappable (GBIC/SFP, XFP) and non-hot-swappable (1*9, SFF).
Optical fiber jumpers have optical fiber connectors installed on both ends. They are mainly used in optical communication rooms, FTTH, LANs, optical fiber data transmission equipment, and testing equipment.
Optical fibers can be divided into single-mode fiber and multi-mode fiber according to the transmission mode of light in the fiber.
Single-mode fiber has a relatively thin core and can only transmit one mode of light, so the inter-model dispersion is small. It is suitable for long-distance communication and is generally G.635 fiber with an inner diameter of 9 μm and yellow outer skin.
Multi-mode fiber such as pm fiber patch cord, has a relatively thick core and can transmit multiple modes of light, but the inter-model dispersion is relatively large. As the transmission distance increases, the inter-model dispersion will gradually increase. It is suitable for short-range communication. The inner diameter of the optical fiber is 62.5μm and 50μm, and its outer skin is orange.
The types of optical fiber connectors used by optical modules mainly include MPO/MTP, SC, ST, FC, LC, MU, and ST.
Transmission distance and data rate
Optical modules have various transmission rates and distances. When choosing optical fiber jumpers for optical modules, it is necessary to choose fiber jumpers that match the optical modules. The Multi-Source Agreement (MSA) specifies the operating wavelength, transmission distance, and data rate of various optical modules and lists the suitable types of optical fibers. This is also a reference for selecting optical fiber jumpers.
When selecting optical fiber jumpers, the interface is an essential consideration. Typically, optical modules have two interfaces (one for receiving optical signals and one for transmitting optical signals), such as duplex SC or duplex LC. Therefore, duplex SC/LC fiber jumpers need to be used. In recent years, new optical modules have only one interface (which can receive and transmit optical signals), requiring single-mode fiber jumpers. Different connectors can be inserted into different devices. If the ports on both ends of the device are the same, MPO-MPO/LC-LC/SC-SC fiber jumpers can be used. If different types of devices need to be connected, use LC-SC/LC/ST/LC-FC fiber jumpers.