Hi Zein: Literally  speaking, the function of a circulator may be considered as that of a switch. For example a combination of a circulator and a FBG can form an add/drop switches used in a multiplexers.

Thanks a lot

Hi,

an optical switch has one or more optical input ports and one or more optical output ports and a control port, which can be electrical or even mechanical. In its simplest form you can see the switch as a shutter: the light can pass or not. Then there are more complicated arrangements like wavelength-selective switches and so on. The optical circulators are instead non-reciprocal devices characterized by a fixed behavior. without control ports. For example, in a N-way circulator, the light entering port 1 is routed as output to port 2, etc until the light entering port N is routed to port 1, hence the name. At the same time, the circulator does not allow the light entering port 2 to go to port 1.

Of course both switches and circulators have an ideal definition and actual behaviour described with various parameters to measure their non-ideality.

Regards

 circulators  can be used as switch  like  in bidirectional networks.

Dear Steve,

The optical circulator is fiber optic device that is able of distributing optical power traveling in opposite directions in one optical fiber. It can be employed to perform bi-directional transmission over a single fiber.

There are two types of optical circulators:  Polarization-Independent Optical circulator, (functionally independent of the polarization of light). In this kind of Optical circulator, the light is not polarized during the propagation to avoid the imperfection of the fiber. The second type is the polarization-dependent optical circulator, which is made a polarization for the light propagation. However, the application of this kind is limited, for instance, optical sensing.

Applications: optical circulators often used to extract optical signals from a reflective device, for example, fiber Bragg gratings. Also, it can be used to as MUX/DEMUX.  Also, circulators are used with a mirror for double passing an optical element to increase efficiency. In fact, the applications of optical circulators are not only for telecommunication industries, but last decade the circulators found a remarkable usage in sensing and imaging fields.  

Features: low back reflection, high extinction ratio, high return loss,                     low insertion loss( less than -1dB), reliable, and stable.  

Next Answer ..... I will provide you some brief information about the switch.  You can ask anything about this answer.  

Best regards,

Musab Tr