Light Transmission

Optical transmission is the technology of transmitting in the form of optical signals between a sender and a receiver. Optical transmission equipment is to convert a variety of signals into optical signals in the optical fiber transmission equipment, so modern optical transmission equipment are usually used in optical fiber. Commonly used optical transmission equipment are: optical transceiver, optical MODEM, optical transceiver, optical switch, PDH, SDH, PTN and other types of equipment. 

Related optical transmission technology brief introduction

Synchronous Optical Network (SONET) and Synchronous Digital Hierarchy (SDH) : A fiber optic transmission system (the former is an American standard used in North America, the latter is an international standard). It takes the synchronous transmission module (STM-1,155Mbps) as the basic concept. The module is composed of net information load, segment overhead, and management unit pointer. Its prominent feature is compatible with various PDH system.

 Plesiochronous Digital Hierarchy (PDH) : Pre-SONET /SDH digital transmission system, non-optical transmission mainstream equipment. It is mainly designed for voice communication. There is no universal standard digital signal rate and frame structure, and international interconnection is difficult. 

Wavelength Division Multiplex (WDM) : Essentially, Frequency Division Multiplex (FDM) is implemented on optical fibers, that is, FDM technology in the optical domain. It is an effective method to improve the capacity of optical fiber communication. In order to make full use of the huge bandwidth resources in the low-loss region of single-mode fiber, the low-loss window of fiber is divided into several channels according to the different frequency (or wavelength) of each channel. They transmit their messages on different wavelengths, so they do not interfere with each other even on the same fiber. Dense Wavelength Division Multiplex (DWDM) : Unlike conventional WDM systems, DWDM systems have narrower channel spacing and better bandwidth utilization. 

Optical Add/Drop Multiplex (OADM) : A device that uses an optical filter or splitter to insert or separate optical signals from a wavelength division multiplexing transmission link. OADM has optical wavelength signals in WDM system to select the above/below required rate, format and protocol type. Only the required wavelength signal is tapped/inserted on the node, and other wavelength signals are optically transparent through the node. Dynamic (flexible, reconfigurable or programmable) OADM is the basis for the realization of metropolitan optical networks. Using dynamic OADM in inter-local optical ring networks, the system can provide full wavelength channel connectivity between any two nodes.

 Optical cross interconnection (OpticalCross-connect, OXC): Equipment used for optical fiber network nodes, through cross connection of optical signals, is an important means to achieve reliable network protection / recovery and automatic wiring and monitoring. It is mainly composed of WDM technology and optical air separation technology (optical switch).

All Optical Network (AON) : refers to the network system in which the signal only undergoes electrical/optical and optical/electric transformation when entering and leaving the network, and always exists in the form of light in the process of transmission and exchange in the network. In other words, the information is always in the optical domain during its transmission from the source node to the destination node, and the wavelength becomes the most basic unit of the all-optical network. The all-optical network is transparent to the signal because all the signal transmission is carried out in the optical domain. The all-optical network realizes the routing through the wavelength selection device. All-optical network has become the first choice of the next generation high-speed (ultra-high-speed) broadband network due to its good transparency, wavelength routing characteristics, compatibility and scalability.

Li-Fi: This optical communication technology uses LED-based indoor light waves instead of radio waves for data transmission. And the top teams in Li-Fi research are looking beyond leds for data transmission, which is laser-based Li-Fi communication technology, which can theoretically improve the rate of Li-Fi over LED by more than 10 times. (In fact, a few years ago, an underwater transmission developed by China Huako, the United States and Iran was able to increase the wireless rate to 300Gb/s at 1 meter distance. The medium used is air.)

The above is a brief introduction to the basic knowledge of optical transmission. I believe you have understood what is optical transmission technology through the above brief explanation. Shenzhen HDV Phoelectron Technology LTD is a manufacturer specializing in optical communication equipment as the main products. In order to provide better quality service for our customers, it is equipped with a strong and excellent R & D technical team. The company’s main products are OLT ONU/ ACONU/ communication optical module/communication optical module/OLT equipment/Ethernet switch and so on, to provide relative services for various needs of customers, welcome your presence.