Wavelength Division Multiplexer working principle



Wavelength Division Multiplexing (WDM) is a technology that transmits multiple wavelengths of optical signals simultaneously in a single fiber. Compared with single-wavelength technology, WDM can save more fiber resources. The basic principle of WDM is to use a wavelength division multiplexer (combiner) at the transmitter side to combine different wavelengths of information optical carriers together into one fiber for transmission, and at the receiver side, another wavelength division multiplexer (splitter) to separate different optical carriers.

WDM systems all work in the 1550nm window. Quartz fiber has three bands available in the 1550 wavelength region, namely S-band, C-band and L-band. The S-band wavelength range is from 1460 to 1530nm, the C-band wavelength range is from 1530 to 1565nm, and the L-band wavelength range is from 1570 to 1605nm.

Wavelength division multiplexing (WDM) with 1310nm/1550nm window is used for access networks, but rarely for long-distance transmission. dense wavelength division multiplexing (DWDM) with 1550nm window: can be widely used for long-distance transmission and used to build all-optical networks. because the multiplexing of 1310/1550nm is beyond the gain range of EDFA, it is only applied in some specialized occasions, so it is often used WDM is a broader name to replace DWDM. 1.25G DWDM and 10G DWDM optical modules are currently used in long-distance transmission of backbone networks.

WDM technology can make full use of the huge bandwidth resources of optical fiber, in a single fiber, WDM transmission capacity is single wavelength several times, tens of times, hundreds of times. In addition, WDM technology signal transparent transmission, the channels of each wavelength are independent of each other, can transmit signals with completely different characteristics and rates, to complete the integrated transmission of various telecommunications services signals, such as PDH signals and SDH signals, digital signals and analog signals, mixed transmission of multiple services (audio, video, data, etc.), etc.

Comments

Post a Comment

Popular posts from this blog

DWDM Optical Equipment - EDFA

Image
Dense Wavelength Division Multiplexing (DWDM) is the ability to combine a set of optical wavelengths for transmission over a single fibre. DWDM technology is an extension of optical networks and the main advantage of DWDM is that it is protocol and transmission rate independent, allowing DWDM-based networks to transmit data over IP, ATM, SONET, SDH and Ethernet. DWDM systems typically have the following optical components: DWDM optical modules, DWDM MUX/DEMUX, DWDM OADM and optical amplifiers. Today we talk about EDFA . The EDFA optical amplifier is an optical fibre amplifier that uses erbium ions as a gain medium. Optical amplifiers amplify optical signals over a wide range of wavelengths, which is important for DWDM system applications. In contrast to EDFAs used in CATV or SDH systems, EDFAs used in DWDM systems are sometimes referred to as DWDM EDFAs. To extend the transmission distance of DWDM systems, one can choose from different types of optical amplifiers, including DWDM EDFAs...
Read more

What is OTN Transmission Technology

Image
OTN transmission technology is a technology that realizes functions such as service signal transmission, multiplexing, and routing in the optical domain. This technology complies with the general model of transmission network specified in ITU-T6.805. From the perspective of OTN network composition level, it can be divided into optical channel layer, circuit layer, optical transmission section layer and optical multiplexing section layer. The OTN network mainly includes key technologies such as optical buffering technology, wavelength conversion technology and optical timing regeneration technology. The OTN network can be regarded as a transition network of the all-optical network, which greatly improves the data transmission capacity of the existing network.   The network survival mechanism of the optical layer and electrical layer of OTN transmission technology is relatively complete, which can ensure the reliable transmission of signals, and has the ability of error correction a...
Read more

Introduction of 100G multi-mode optical modules—SR4/SRBD/SWDM4

Image
With the rapid development of 5G, AI, big data, cloud computing and other services, the data center network is required to develop in the direction of high speed, high density, and efficient operation and maintenance. At present, 100G is widely used in China. This article introduces three mainstream solutions for 100G multimode optical modules. 1) 100G QSFP28 SR4 Interface type: multi-mode MPO-12F working principle: The center wavelength of 100GBASE-SR4 is 850nm, which can provide four independent transmission and reception channels, and the operating rate of each channel can reach 25G. The transmission distance is 70m when used with OM3 multimode fiber and 100m when used with OM4 multimode fiber. 2) 100G QSFP28 SRBD Interface type: multimode duplex LC working principle The transmission wavelength of the 100GBASE-SRBD optical module is 850nm and 900nm, and the SWDM wavelength division multiplexing technology is used to multiplex the optical signals of different wavelengths in the same...
Read more