2025-06-19
Polarization maintaining optical circulators are very important components in the line of an advanced optical communication and sensing system. In deploying the polarization maintaining optical circulator, many things must be considered, so that the circulator will perform optimally and will somehow fit into a system.
So, let us look at what factors are considered for deploying a polarization maintaining optical circulator.
One of the first considerations when attempting to deploy a polarization maintaining optical circulator is ensuring the alignment with the polarization axis of the PM fibers to which the circulator is being connected. The circulator must ensure a perfect match between the polarization axes of the incoming and outgoing fibers.
Keep in mind that manufacturers of circulators may allow unique marking for quick orientation of the device either as to the slow or fast axes prior to splicing.
Insertion loss is the amount of optical power diminished when light travels through the polarization maintaining optical circulator. The lower the insertion loss, the more it points to hardly any signal strength being lost during transmission.
Return loss is also an important factor. It determines how much light gets bounced back. Higher return loss is required to prevent any glitches from upstream components, especially in laser-based systems. The designers have to make trade-offs among these losses along with the requirement to maintain the circulator polarization.
The ability of a polarization maintaining optical circulator to preserve the input polarization state is known as its extinction ratio. A higher extinction ratio would mean less polarization crosstalk, which is important for applications in coherent communication and interferometry.
Environmental influences during deployment, such as mechanical stress or temperature variation, can disrupt polarization maintenance. Consequently, this calls for choosing a circulator with a rugged design providing stable extinction ratios under different conditions, thus ensuring long-term reliability.
In any optical system, isolators are supposed to direct light from one port to another without back reflection. The peculiarity of polarization maintaining an optical circulator lies in doing it whilst maintaining a polarization leastwise. High isolation between ports avoids leakage and ensures a clean set of signals.
The assessment of a circulator’s isolation performance has to be conducted not only at its nominal operating point but also when it is subject to real-world environmental stresses such as vibration and humidity.
A polarization-maintaining optical circulator has to perform its operations under thermal/mechanical load variations robustly. Variations in temperature can cause variations in birefringence in the fiber and thus variations in polarization states. Similarly, vibration incidents can misalign the axes.
The preferred devices for harsh environments are those with ruggedized packaging and internal stress-relieving mechanisms. The circulator housing material should also have low thermal expansion properties so that the optical alignment can be maintained with lesser temperature-induced distortions.
Get in touch with DK Photonics if you are looking for a reliable polarization maintaining optical circulator.
