Optical modules are optoelectronic devices that perform photoelectric and electro-optical conversion. The transmitting end of the optical module converts the electrical signal into an optical signal, and the receiving end converts the optical signal into an electrical signal. The following shows the application of optical modules in various industries. The main application fields of optical modules include: 1. Data center; 2. Mobile communication base station; 3. Passive wavelength division system; 4. SAN/NAS storage network; 5. 5G bearer network.
The current data center is no longer just one or several computer rooms, but a group of data center clusters. In order to realize the normal work of various Internet services and application markets, data centers are required to operate in coordination. The real-time mass exchange of information between data centers has created the demand for data center interconnection networks, and optical fiber communication has become a necessary means to achieve interconnection.
Different from traditional telecom access network transmission equipment, data center interconnection requires higher speed, lower power consumption, and more miniaturization of switching equipment to achieve larger and more intensive transmission of information. A core factor that determines whether these performances can be realized is the optical module.
Data center communication optical modules can be divided into three categories according to the connection type:
(1) From the data center to the user, generated by end-user behaviors such as accessing the cloud to browse the web, send and receive emails, and video streams;
(2) Data center interconnection, mainly used for data replication, software and system upgrades;
(3) Inside the data center, it is mainly used for information storage, generation and mining. According to Cisco’s prediction, the internal communication of the data center accounts for more than 70% of the data center communication, and the great development of the data center construction has also given birth to the development of high-speed optical modules.
A mobile communication base station refers to a radio transceiver station that transmits information between a mobile communication switching center and a mobile phone terminal in a certain radio coverage area.
The operator’s mobile communication base station also needs optical modules to realize the interconnection between devices. The base station has RRU and BBU devices. In the application, we need to connect the links between these two devices, which requires our optical modules. In the 4G network, the equipment used to connect the BBU and RRU is mainly 1.25G optical module, 2.5G optical module, 6G optical module, 10G optical module, etc.
Among the technical solutions adopted in 5G fronthaul, passive WDM undoubtedly accounts for the highest proportion. Passive WDM system consists of color optical module, multiplexer and optical fiber.
The core principle of passive wavelength division technology is to use WDM technology to couple optical signals with different wavelengths and carrying a series of information into one bundle, and transmit them in one optical fiber to realize the transmission between services. WDM can simultaneously transmit multiple signals along a single optical fiber. It can transmit each signal with a specific wavelength of light that matches the signal, and the optical signals of different wavelengths can be separated at the receiving end. The passive wavelength division system is mainly a system composed of two parts: color light module and optical terminal multiplexer.
With the rapid development of the Internet and network applications, the types of data to be processed by the data information storage system are also explosively increasing, which makes the data information storage system face unprecedented challenges. Additional network storage devices (Network Attached Storage, abbreviated as NAS) and regional storage networks (Storage Area Network, abbreviated as SAN), they can separate the data information storage device from the network and the host system, both centralized management of information data, and With good scalability, it provides the most effective solution for realizing centralized data management.
The main function of the SAN/NAS storage network is to store data. Among them, the SAN network is mainly composed of servers, fiber channel switches, storage devices, and transmission carriers (optical modules, optical fiber jumpers); the NAS storage network is mainly composed of NAS storage, switches, Composed of terminal equipment (computer), transmission carrier (optical module, optical fiber jumper).
It should be noted that the SAN network uses Fiber Channel optical modules and needs to support the FC Fiber Channel protocol, while the optical modules used in the NAS storage network only need to conform to the Ethernet protocol.
The 5G network is divided into three parts, namely the access network, bearer network and core network. To understand the relationship between them, you can refer to the following picture:
The 5G bearer network is generally divided into a metropolitan access layer, a metropolitan aggregation layer, a metropolitan core layer/provincial trunk line, and realizes the fronthaul and midhaul functions of 5G services.
Typical application scenarios of 5G fronthaul include direct fiber connection, passive WDM and active WDM, etc.
Typical requirements for optical modules in 5G fronthaul application scenarios are as follows:
①Meet the temperature of industrial grade, high reliability requirements: Considering the outdoor working environment, the fronthaul optical module must meet the industrial grade temperature range of -40℃～+85℃, and also need to meet the dustproof requirements
②Low cost: The demand for 5G optical modules greatly exceeds that of 4G, especially for fronthaul optical modules. Low cost is one of the main requirements for optical modules in the 5G industry. 5G medium and backhaul covers the metropolitan access layer, aggregation layer and core layer. The required optical modules are not much different from the optical module technology used in the current data center. The access layer will mainly use 25Gb/s, 50Gb/s, 100Gb/s s and other rate optical modules, the convergence layer and above will mostly use DWDM optical modules with rates of 100Gb/s, 200Gb/s, 400Gb/s and so on.
Finally, it has to be said that the growth demand of optical modules mainly depends on the data communication market and the telecom market. In today’s data age, optical modules are bound to usher in new development opportunities.