Six major differences and distinguishing methods of single-mode and multi-mode of optical modules

The optical module (opTIcalmodule) is composed of an optoelectronic device, a functional circuit, an optical interface, and the like, and the optoelectronic device includes two parts: transmitting and receiving. The transmitting part is: an electric signal inputting a certain code rate is processed by an internal driving chip to drive a semiconductor laser (LD) or a light emitting diode (LED) to emit a modulated light signal of a corresponding rate, and an optical power automatic control circuit is internally provided therein. The output optical signal power remains stable. The receiving part is: the optical signal input module of a certain code rate is converted into an electrical signal by the photodetecting diode. After the preamplifier, the electrical signal of the corresponding code rate is output.

Simply put, the function of the optical module is photoelectric conversion, and the transmitting end converts the electrical signal into an optical signal. After transmitting through the optical fiber, the receiving end converts the optical signal into an electrical signal.

A single mode in an optical module actually refers only to the type of fiber. The single-mode optical module is an optical module used together with a single-mode optical fiber. The LD or a narrow-spectrum LED is used as a light source to transmit a very high-bandwidth data signal, so the transmission distance is very long. The mark on the single-mode optical module is "SM", and the fiber is yellow, mainly based on the wavelength near the window of 1310 nm and 1550 nm.

The bandwidth potential of single mode in a single-mode optical module makes it the best choice for high-speed and long-distance data transmission. It is mostly used for long-distance transmission such as LR, ER/ZR, etc., where the transmission rate is relatively high, such as long-distance trunk transmission. , metropolitan area network construction, etc. Wide range of applications, including telecommunications, cable TV, railway, military, financial securities, customs, civil aviation, shipping, electricity, water and oil fields, and other broadband data networks and areas requiring high reliability data transmission or IP data transmission private network It is the most ideal application equipment for broadband campus network, broadband cable TV network and intelligent broadband cell fiber to the building and fiber to the home.

The optical module used in conjunction with the multimode fiber to obtain the best transmission characteristics is called a multimode optical module, which can transmit multiple modes of light, and the appearance is as shown in the following figure. Multimode optical modules are generally used for short-distance transmission because of the large dispersion between modes, which limits the frequency at which digital signals are transmitted.

Generally, the multimode optical wavelength is 850 nm, and the single mode optical wavelength is mainly 1310 nm and 1550 nm. Multimode optical modules can only be used for short-distance transmission (SR) due to the serious dispersion between modes, while single-mode optical modules are mostly used for long-distance transmission such as LR, ER, and ZR. Normally, a transmission distance of less than 2 km is called a multimode module; a transmission distance of 2 km or more is called a single mode module.

Multimode optical modules are mostly used in networks with relatively low transmission rates and relatively short transmission distances, such as local area networks. Such networks usually have many nodes, multiple connectors, many bends, large amounts of connectors and couplers, and units. The length of the fiber uses a large number of light sources. The multi-mode optical module can effectively reduce the network cost. The single-mode optical module is mostly used in long transmission lines and relatively high transmission rates, such as long-distance trunk transmission and metropolitan area network construction. Wait.

A single mode in an optical module actually refers only to the type of fiber. According to the transmission mode of the optical module in the optical fiber, it can be classified into a single mode fiber and a multimode fiber.

The multimode fiber is abbreviated as MMF, and the fiber diameter is generally 50/125 μm or 62.5/125 μm.

The single mode fiber is referred to as SMF, and the fiber diameter is 9/125 μm.

The single-mode optical module uses twice as many components as a multimode optical module, so the overall cost of a single-mode optical module is much higher than that of a multi-mode optical module.

The light source of the multimode optical module is a light emitting diode or a laser, and the light source of the single mode optical module is an LD or a LED with a narrow spectral line.

Single-mode optical modules are often used for long-distance transmission with transmission distances of 150 to 200 km. The multimode optical module is used for short-distance transmission with a transmission distance of up to 5km.

In addition to the above differences between the two can be distinguished, it can also be distinguished from the manufacturer:

1, multimode optical module

Model: GLC-SX-MM

Description: SFP, 1000Base-SX Gigabit optical module, 850 nm, multimode 550 m

2, single mode optical module

Model: GLC-LH-SM

Description: SFP, 1000Base-LX Gigabit optical module, 1310 nm, single mode 10km

1, multimode optical module

Model: eSFP-850nm-1000Base-Sx/FC200 MM

Description: Optical transceiver module (eSFP, 850nm, 2.125Gb/s multi-rate, -9.5dBm~-2.5dBm, -17dBm, LC, multimode, 0.5km)

2. Single mode optical module 10km

Model: eSFP-1310nm-1000Base-Lx SM

Description: Optical transceiver module-eSFP-1310nm-1.25Gb/s--9dBm--3dBm--20dBm-LC-single mode-10km

Portable Outdoor Power

Portable Outdoor Power,Outdoor Power Bank,Outdoor Battery Bank,Outdoor Portable Power

SUZHOU DEVELPOWER ENERGY EQUIPMENT CO.,LTD , https://www.fisoph-power.com