In sophisticated optical communication systems, the optical circulator has become one of the most critical components. It’s used to split optical signals in an optical cable that is traveling in different directions.
Optical circulators have been widely used in a variety of disciplines, including telecommunications, medicine, and imaging. We’ll learn more about the optical circulator in this article.
What Is an Optical Circulator?
An optical circulator is a device that allows light to travel from one optical cable to the next. It’s a non-reciprocal device that routes light dependent on the propagation direction. Light can be moved forward using both an optical circulator and an optical isolator. In contrast to the optical circulator, the optical isolator often loses more light energy.
Optical circulators typically have three ports, two of which are utilized as input ports and one as an output port. A signal is sent from port 1 to port 2, followed by another signal from port 2 to port 3. Lastly, the third signal can be sent from port 3 to port 1. Because many applications only need two, they can be designed to prevent any light that enters the third port.
Optical Circulator Components Technologies
The following components make up an optical circulator:
Faraday Rotator
Faraday rotators use the Faraday effect, which is the rotation of the polarization plane of electromagnetic waves in a material subjected to a magnetic field parallel to the wave’s propagation direction.
Birefringent Crystal (Birefringent Crystal):
The polarization state of the light beam and the relative orientation of the crystal affect light propagation in the birefringent crystal. The beam’s polarization can be adjusted, or the beam can be split into two orthogonal polarization states.
Beam Displacer and Waveplate
Birefringent crystals come in two varieties: waveplate and beam displacer. A waveplate is formed by cutting a birefringent crystal to a particular orientation in which the crystal’s optic axis is parallel to the crystal border and in the incident plane. An entering beam is separated into two beams with orthogonal polarization states using a beam displacer.
Optical Circulator Classifications
According to the concept of polarization:
Polarization-dependent optical circulators and polarization-independent optical circulators are two types of optical circulators. The former is employed for light with a specific polarization state, whereas the latter is not limited to a light’s polarization state.
The vast majority of optical circulators used in fiber optic communications are polarization-independent.
In terms of functionality:
There are two types of optical circulators: full circulator and quasi-circulator. In a complete cycle, a full circulator makes use of all ports. Light travels from port 1 to port 2, then from port 2 to port 3, and finally from port 3 to port 1.
Light travels through all ports sequentially in a quasi-circulator, but the light from the last port is lost and cannot be sent back to the first port. A quasi-circulator is sufficient for most purposes.
Conclusion
You may now have a general idea of what an optical circulator is. Using an optical circulator to route light signals with minimal loss is a cost-effective and efficient approach.