As the core device in optical fiber transmission, the optical module’s various indicators determine the overall performance of the transmission. The optical module is the carrier used for transmission between the switch and the device, and its main function is to convert the electrical signal of the device into an optical signal at the transmitting end. The basic structure consists of two parts: “light emitting component and its driving circuit” and “light receiving component and its receiving circuit”. So what is the working principle of the optical module and what are the applications of the optical module, do you understand it clearly? Let’s take a look at the text together!
Table of Contents
What Is the Working Principle of the Optical Module?
- The composition and principle of the sending channel
The emission channel of the optical module is composed of an electrical signal input interface, a laser drive circuit, an impedance matching circuit and a laser component TOSA.
Its working principle is that the electrical interface input of the transmitting channel completes the coupling of the electrical signal through the electrical interface circuit, and then goes through the laser driving circuit in the transmitting channel for modulation, and then goes through the impedance matching part for impedance matching to complete the modulation and driving of the signal. The input laser (TOSA) is electro-optically converted into an optical signal for optical signal transmission.
- The composition and working principle of the receiving channel
The receiving channel of the optical module is composed of a photodetector component ROSA (composed of a photodetector diode (PIN), a transimpedance amplifier (TIA)), an impedance matching circuit, a limiting amplifier circuit and an electrical signal output interface circuit.
Its working principle is that the PIN converts the collected optical signal into an electrical signal in direct proportion, and the TIA converts the electrical signal into a voltage signal, amplifies the converted voltage signal to the required amplitude, and transmits it to the limiter through the impedance matching circuit. The amplifier circuit completes the re-amplification and shaping of the signal, improves the signal-to-noise ratio, reduces the bit error rate, and finally the electrical interface circuit completes the signal output.
What Are the Applications of Optical Modules?
As the core device for photoelectric conversion in optical communication, optical modules are widely used in data centers. Traditional data centers mainly use 1G/10G low-speed optical modules, while cloud data centers mainly use 40G/100G high-speed modules. With the rapid growth of global network traffic driven by new application scenarios such as high-definition video, live broadcast, and VR, in order to cope with future development trends, emerging application requirements such as cloud computing, IaaS services, and big data have put forward higher requirements for data transmission within data centers. This will lead to higher propagation rate optical modules in the future.
Generally, we choose optical modules mainly considering factors such as application scenarios, data transmission rate requirements, interface types, and optical transmission distance (fiber mode, required optical power, center wavelength, laser type).