Shulou(Shulou.com)11/24 Report--

The original title: "it's not an exaggeration. Without an optical module, there would be no optical communication."

Over the past 100 years, human beings have developed from simple Telegraph communication to 5G communication. Life has undergone earth-shaking changes. Live broadcast, VR / AR, ultra-clear video conferencing, telemedicine, self-driving and smart home are more and more widely used. All of these need to be based on high-speed data transmission.

Because the high-speed signal attenuates rapidly in the copper cable and can not achieve long-distance transmission, at the same time, because the transmission frequency of optical signal is more than 1000 times higher than that of radio signal, the transmission rate of information is effectively improved. Optical fiber has gradually become the mainstream transmission medium.

Within the computer, memory and switch, the data is processed and transmitted in the form of electrical signals. So, how to convert electrical signals into optical signals into optical fiber? Or how to convert the optical signal in the optical fiber into electrical signal and connect it to the communication system?

Therefore, the optical module, the magician of the communication world, arises at the historic moment! He realized the photoelectric conversion.

1. The status of the optical module since its birth, the optical module has always had an unshakable status! The bigwigs of the communications world commented like this:

"without an optical module, there would be no optical communication."

"Optical modules are required for all 5G carrier technologies."

"No matter which 5G carrier standards and technologies are ultimately inseparable from the support of optical modules, long-distance, low-cost, high-speed optical modules are the key elements to achieve low-cost and wide coverage of 5G."

……

2. The functional optical module of the optical module is usually composed of optical emitting module (including laser), optical receiving module (including detector), driving circuit and photoelectric interface, and the structure is shown in the following figure.

Schematic diagram of optical module structure (SFP + package) (picture from optical module white paper)

In optical communication, the transmission and reception of information are realized by optical modules.

1. At the sending end, the optical module completes the electrical / optical conversion.

two。 Light travels in an optical fiber.

3. At the receiving end, the optical module realizes the optical / electrical conversion.

3. The development of optical module Optical module is the basic unit of 5G network physical layer, which is widely used in wireless and transmission equipment. For 5G bearer, 25Compact 100Gb / s high-speed optical module will be gradually introduced in the forward, intermediate and backhaul access layer, and N × 100swap 200x400 Gb / s high-speed optical module will be introduced in the backhaul convergence and core layer.

The development trend and technical route of optical modules are shown in the following figure.

Below from the three main features of the optical module to introduce.

The determination of the packaging form standard makes the optical modules produced by various manufacturers compatible and interconnected.

Packaging form is the most important feature of optical module. With the development of optoelectronic devices, the bandwidth of devices and chips increases gradually. With the increase of the bandwidth of devices and chips, with the development of photonic integration technology, optical modules also achieve higher speed transmission and smaller size packaging.

The following figure shows the development of optical module packaging.

The high-speed data transmission makes various applications of 5G possible.

Transfer rate refers to the number of bits transmitted per second, in Mb / s or Gb / s. The optical module has gradually climbed from 155 Mb / s to 622 Mb / s, 1.25Gb / s, 2.5Gb / s, 10Gb / s, 25, 50, 100 Gb / s, 200 Gb / s, 400 Gb / s, 800 Gb / s.

In order to achieve higher rates, there are usually three solutions:

In the field of optical communication, faster and farther transmission distance has always been the unremitting pursuit of communicators.

The transmission distance of optical module is mainly SR (100m), LR (10 km), ER (40 km) and ZR (80 km). With the construction of data center network, in order to have more cost-effective wiring, two transmission distances of DR (500m) and FR (2 km) are further derived. Common optical module transmission distances are as follows:

The higher the rate, the shorter the transmission distance. If the distance exceeds the above limit, fiber amplifiers such as EDFA (Erbium Doped Fiber Amplifier, Erbium-doped Fiber Amplifier) can be used to amplify weak optical signals and transmit them farther, or coherent optical modules can be used to transmit them. Of course, neither of them is cheap and requires extra cost.

With the advent of the 5G era and the popularity of the Internet of things, the information generated is growing explosively, which puts forward higher transmission performance requirements for the physical layer of the whole communication system. As an important part, optical module will continue to contribute to the development of communication.

This article comes from the official account of Wechat: ZTE document (ID:ztedoc), author: ZTE document

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