Hi Ranjeet,
ptical Circulators are non-reciprocating, one-directional, three port devices which are great for bidirectional propagation
of light in a single fiber.In fiber optical networks passive components such as optical isolators are essential for delivering of signals with minimum loss. Another type of passive element that is commonly used in fiber optic systems is the optical circulator. These devices that are used to direct the optical signal from one port to another port and in one direction only. This action prevents the signal from propagating in an unintended direction. Optical circulators have continued to increase their presence in a broad array of applications, including optical amplifiers, optical add and drop systems, dense wavelength-division multiplexing (DWDM Mux) networks and, optical time domain reflectometers (OTDRs).n a 3-port circulator a signal is transmitted from port 1 to port 2, another signal is transmitted from port 2 to port 3 and, finally, a third signal can be transmitted from port 3 to port 1. The name derives from the fact that a signal is transmitted from Port 1 to Port 2, another signal can be transmitted from Port 2 to Port 3 and, finally, a signal can be transmitted from Port 3 to Port 1. In practice, one or two ports are used as inputs and the third port is used as the output.
Thanks,