What are the characteristics and applications of fiber optic circulators?

The outstanding feature of the fiber optic circulator, also known as the isolator, is the one-way transmission of high-frequency signal energy. It controls the transmission of electromagnetic waves along a certain circular direction. This characteristic of one-way transmission of high-frequency signal energy is mostly used between the output end of the high-frequency power amplifier and the load, which plays a role of being independent and "isolated" from each other. The load impedance does not affect the working state of the power amplifier even under the condition of open circuit or short circuit, thus protecting the power amplifier.

The principle of one-way transmission of the circulator is due to the use of ferrite gyromagnetic materials. This material produces gyromagnetic properties (also known as tensor permeability properties) under the combined action of an external high-frequency wave field and a constant DC magnetic field. It is this gyromagnetic characteristic that makes the electromagnetic wave propagating in the ferrite rotate polarized (Faraday effect), and the electromagnetic wave energy is strongly absorbed (ferromagnetic resonance). It is this gyromagnetic phenomenon that makes the structure. Type isolators, circulators. It has the characteristics of small size, wide frequency band, small insertion loss, etc., so it is widely used.