随着光通信的高速发展，现在我们工作和生活中很多场景都已经实现了“光进铜退”。也就是说，以同轴电缆、网线为代表的金属介质通信，逐渐被光纤介质所取代。
而光模块，就是光纤通信系统的核心器件之一。
光模块的组成结构
光模块，英文名叫Optical Module。Optical，意思是“视力的，视觉的，光学的”。
准确来说，光模块是多种模块类别的统称，具体包括：光接收模块，光发送模块，光收发一体模块和光转发模块等。
现今我们通常所说的光模块，一般是指光收发一体模块（下文也是如此）。
光模块工作在物理层，也就是OSI模型中的层。它的作用说起来很简单，就是实现光电转换。把光信号变成电信号，把电信号变成光信号，这样子。
虽然看似简单，但实现过程的技术含量并不低。
一个光模块，通常由光发射器件（TOSA，含激光器）、光接收器件（ROSA，含光探测器）、功能电路和光（电）接口等部分组成。
在发射端，驱动芯片对原始电信号进行处理，然后驱动半导体激光器（LD）或发光二极管（LED）发射出调制光信号。
在接收端，光信号进来之后，由光探测二极管转换为电信号，经前置放大器后输出电信号。
光模块的封装
对于初学者来说，光模块最让人抓狂的，是它极为复杂的封装名称，还有让人眼花缭乱的参数。
封装，可以简单理解为款型标准。它是区分光模块的最主要方式。
之所以光模块会存在如此之多的不同封装标准，究其原因，主要是因为光纤通信技术的发展速度实在太快。
光模块的速率不断提升，体积也在不断缩小，以至于每隔几年，就会出新的封装标准。新旧封装标准之间，通常也很难兼容通用。
此外，光模块的应用场景存在多样性，也是导致封装标准变多的一个原因。不同的传输距离、带宽需求、使用场所，对应使用的光纤类型就不同，光模块也随之不同。
With the rapid development of optical communication, many scenes in our work and life have realized “light forward copper backward”. In other words, the metal media communication represented by coaxial cable and network cable is gradually replaced by optical fiber media.
Optical module is one of the core components of optical fiber communication system.
The structure of an optical module
Optical Module, also known as Optical Module. Optical means visual, visual, or optical.
Accurately speaking, optical module is a general term for a variety of modules, including: optical receiving module, optical transmitting module, optical transceiver integrated module and optical forwarding module.
Nowadays, we usually refer to the optical module, generally refers to the optical transceiver integrated module (the following is also the case).
Optical modules work at the physical layer, the lowest level of the OSI model. Its function is very simple, is to convert electricity to light. Turn an optical signal into an electrical signal, turn an electrical signal into an optical signal, like that.
While seemingly simple, the implementation is not low-tech.
An optical module usually consists of an optical emitting device (TOSA, including a laser), an optical receiving device (ROSA, including an optical detector), a functional circuit and an optical (electrical) interface.
At the transmitter, the driver chip processes the original electrical signal and then drives a semiconductor laser (LD) or light-emitting diode (LED) to emit a modulated optical signal.
At the receiving end, after the optical signal comes in, the optical detection diode is converted into an electrical signal, and the electrical signal is output after the preamplifier.
Encapsulation of optical modules
For starters, the most frustrating thing about optical modules is their complex package names and bewildering parameters.
Encapsulation, which can be simply understood as a type standard. It is the main way to distinguish optical modules.
The reason why there are so many different packaging standards for optical modules is mainly because the development speed of optical fiber communication technology is too fast.
Optical modules are getting faster and smaller, so much so that every few years, new packaging standards are introduced. Compatibility between old and new packaging standards is also often difficult.
In addition, the diversity of application scenarios of optical modules is also a reason for the increasing number of packaging standards. According to the transmission distance, bandwidth requirements, and application sites, the types of optical fibers and optical modules are different.
