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Single Mode Fiber Optic Circulators
Thorlabs’ Single Mode (SM) Optic Circulators are non-reciprocating, one directional, three-port devices that are used in a wide range of optical setups and for numerous applications. Our SM optical circulators have a center wavelength of 1064, 1310 (O-Band), or 1550 nm (C-Band). Additionally these SM optical circulators are available unterminated, with FC/PC connectors, or with FC/APC connectors. Thorlabs also offers Polarization-Maintaining (PM) Fiber Optical Circulators.
An optical circulator is analogous to an electronic circulator and both perform similar functions. An optical circulator is a three-port device that allows light to travel in only one direction. A signal entering to Port 1 will exit Port 2 with minimal loss, while a signal entering Port 2 will exit Port 3 with minimal loss. Light entering port 2 experiences a large amount of loss at port 1, and light entering port 3 experiences a large amount of loss at ports 2 and 1. Optical circulators are non-reciprocal devices. This means that any changes in the properties of the light caused by passing through the device are not reversed by traveling in the opposite direction.
Because of its high isolation and low insertion loss, optical circulators are widely used in advanced communication systems as add-drop multiplexers, bi-directional pumps, and chromatic dispersion compensation devices.
Circulators can be used to send optical signals through a single fiber in two directions.
The example to the left depicts the use of a circulator to drop an optical channel from a DWDM system using a Fiber Bragg Grating (FBG). The input DWDM channels are coupled into Port 1 of the device with a FBG device connected to Port 2. The single wavelength reflected from the FBG then reenters the circulator in port 2 and is routed accordingly to Port 3. The remaining signals pass through the FBG and exit on the top fiber.
Circulators can also be used to send optical signal in two directions down a single fiber. A circulator is located at both ends of the fiber. Each circulator functions to add a signal in one direction while removing the signal in the other. See the example to the right.
For custom wavelength and connector options please contact Technical Support.
Thorlabs' 1064 nm SM Fiber Optic Circulators are available unterminated, with FC/PC connectors, or with FC/APC connectors. The FC/PC and FC/APC connectors have a 2 mm narrow key.
Thorlabs' 1310 nm SM Fiber Optic Circulators are available unterminated, with FC/PC connectors, or with FC/APC connectors. The FC/PC and FC/APC connectors have a 2 mm narrow key. Our CIR1310, CIR1310-FC and CIR1310-APC circulators have a damage threshold of 300 mW. The CIR-1310-50-APC broadband fiber optic circulator is specifically designed for OCT applications. This circulator boasts a broader wavelength range than our standard 1310 nm SM fiber optical circulator and has a damage threshold of 500 mW. For more information, please see our full presentation on our circulator for OCT.
Thorlabs' 1550 nm SM Fiber Optic Circulators are available unterminated, with FC/PC connectors, or with FC/APC connectors. The FC/PC and FC/APC connectors have a 2 mm narrow key.