What Is an Optical Coupling?
Optical coupling is to split or combine the optical power of the same wavelength. Through the optical coupler, we can synthesize two optical signals into one, which is mainly used to transmit signals and realize the photoelectric conversion of the model.
- coupling:
- It refers to the phenomenon that there is close coordination and mutual influence between the input and output of two or more circuit elements or electrical networks, and the energy is transmitted from one side to the other through interaction. Coupling as a noun has related terms in communication engineering, software engineering, mechanical engineering and other projects. In the popular sense, it means alignment, union and adhesion.
- Optical coupling:
- Optical coupling is to split or combine the optical power of the same wavelength. It is mainly used to transmit signals and realize photoelectric conversion of models. It can also be understood as directing light to certain devices, such as coupling light into an optical fiber or coupling different lights. [1]
- Example: Photosynthesis in fiber optics
- The optical coupling problem in the fiber optical path mainly includes the following various practical situations.
- 1. Permanently combine two (root) or more sections of optical fiber, such as fiber fusion splicing and fusion cone type fiber couplers,
- 2. Separately connect two (root) or more optical fibers, such as detachable optical fiber connectors and mobile optical fiber switches, etc .;
- 3. Between two (root) or multiple fiber end faces, insert the necessary tiny optical components, such as lenses, optical flags, small prisms, modulation disks, sensitive components, etc., to form a fiber optical path device with various functions, For example, optical switches, optical wavelength division multiplexing / demultiplexing, optical couplers, optical circulators, fiber optic sensors, and so on. In addition, as a whole fiber optical path system, of course, there is also a problem of optical coupling between a light source and a light detector and an optical fiber. In this way, the optical coupling problem in the fiber optical path is an important and quite complex problem. [2]
Optical coupling
- Optical coupler (OC for short) is also called opto-isolator, which is called optical coupler for short. Optical couplers use light as a medium to transmit electrical signals. It has good isolation for input and output electrical signals, so it is widely used in various circuits. In recent years, it has become one of the most diverse and widely used optoelectronic devices. Optical couplers are generally composed of three parts: light emission, light reception, and signal amplification. The input electric signal drives a light emitting diode (LED) to cause it to emit light of a certain wavelength, which is received by a photodetector to generate a photocurrent, which is then amplified and output.
- Because the input and output of the optocoupler are isolated from each other, and the electrical signal transmission has the characteristics of unidirectionality, it has good electrical insulation and anti-interference ability. And because the input end of the optocoupler is a low-resistance component that works in current mode, it has a strong common mode rejection capability. Therefore, it can greatly improve the signal-to-noise ratio as a terminal isolation element in long-line transmission information. As a signal isolation interface device in computer digital communication and real-time control, it can greatly increase the reliability of computer work.
- The main advantages of the optocoupler are: the signal is transmitted in one direction, the input and output are completely electrically isolated, the output signal has no effect on the input, strong anti-interference ability, stable work, no contact, long life, transmission efficient. [1]
Photocoupler Photocoupler
- A photocoupler is an electrical-optical-electrical conversion device that transmits electrical signals using light as a medium. It consists of a light source and a light receiver. The light-emitting source and the light-receiver are assembled in the same closed casing, and are separated from each other by a transparent insulator.
- The advantages of photocouplers are small size, long life, no contact, strong anti-interference ability, noise isolation, wide operating temperature, electrical insulation between input and output, unidirectional transmission of signals and easy connection of logic circuits.
- Three series of photocoupler circuit diagrams