Classification, Effect, Working Principle and Characters of Optical Isolator

Optical Isolator is an optical passive device that only allows passing through of one-way light, whose effect is to limit direction of light and keep light transports in a single direction. Thus, via fiber optic cables echo reflected light can be isolated by Optical Isolator to improve optical transmission efficiency. This article, I will focus on classification, working principle and features of Optical Isolator.

For the purpose of satisfying demand of different fields, Optical Isolator Manufacturer produced various kinds of Optical Isolator, mainly include: In-Line Isolator, Free Space Isolator and Fiber Optical Isolator and so on. It is widely used in optical fiber amplifier, fiber laser, fiber CATV net and satellite communication and so many fields. Generally speaking, wavelength of Optical Isolator is from 800nm to 1300nm, of course, there are some exceptions.
Now let's have a look at working principle of free space isolator: magneto-optical crystal Faraday Effect. As shown in the following, forward incoming signal light turns to linearly polarized light through polarizer. Faraday rotation magnetic media and external magnetic field make signal light have a 45 degree rotation at right. To backlight, when linearly polarized light pass through place media, its direction also have a 45 degree turning at right, thus, make polarization direction of backlight cross-cut with polarizer to completely block the transportation of reflected light.
Besides, follow me to effect of Optical Isolator. That is to prevent all bad influences on light source and light system caused by after transmission light. For example, install an Optical Isolator between diode laser source and light transmission system can decrease bad effect that reflected light have on stability of spectra of the light output power. At the same time, in the system of high speed direct modulation and direct detection of optical fiber communication, backward transmission light will produce extra noise which can make the system performance degradation. At this time, Optical Isolator is needed to remove the noise. Apart from these, installation of in-line isolator at both sides of fiber amplifier can improve working stability of fiber amplifier.
The most important thing is the characters of Optical Isolator. Due to its high isolation, low insertion loss, high reliability, high stability, extremely low polarization loss and polarization mode dispersion, it is widely accepted by customers all over the world. That's why so many Optical Isolator Manufacturers are flooding into the international market to challenge the fierce competition and manage to make their product a good selling point.
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