Before understanding PM optical isolators, it’s important to know what optical isolators are. So, we will start by discussing the optical isolators and then help you find the answers you are looking for.
Definition of an Optical Isolator
An optical isolator is a passive component based on fiber-optics technology and allows the light signals to propagate in only one direction while blocking the reflections. An optical isolator consists of a Faraday rotator sandwiched between two polarizers.
Definition of a PM Optical Isolator
Here, PM stands for polarization-maintaining. A polarization-maintaining (PM) isolator is an optical isolator that guides optical light in only one direction while preserving its polarization state and eliminating the back reflections.
It blocks and isolates the system from the scattering of reflections in the reverse direction and helps improve the overall performance and efficiency of the optical and light-wave systems.
Why does polarization matter?
When dealing with applications and systems that utilize fiber optics technology, it’s critical to consider the polarization of the light. Even though the priority is given to the wavelength and intensity of the light in most optical systems, polarization is a crucial property of light that affects even those optical systems that don’t measure it explicitly.
Polarization of light has the capability to influence the focus of laser beams and the cut-off wavelength of filters. Plus, it also plays a substantial role in preventing unwanted back reflections.
Thus, for applications where you cannot allow the reflections of polarized light to impact the efficiency and performance of the systems and you need to maintain the polarization state of the light, what you need is a PM optical isolator.
What if PM optical isolators are not used in certain optical applications?
With the absence of PM optical isolators, the light source that emits the light wave or light signal gets exposed to back reflections and scattered signals that ultimately lead to intensity noise and optical damage. By using PM optical isolators, you can achieve greater isolation and higher return loss. Hence, they make the perfect choice for applications that are highly sensitive to optical feedback and reflections.
How are optical isolators different from PM optical isolators?
When it comes to differentiating optical isolators and PM optical isolators, the main difference is that the latter helps retain the polarization state of the incoming light while isolating the light source from any damage.
What You Should Know About Optical Isolators before Purchasing
When searching for optical isolators online, you will notice the term “TGG -based”. TGG (Terbium Gallium Garnet) is a crystal that is widely used as magneto-optic material in Faraday rotators that are the basic part of optical isolators and PM optical isolators.
The primary reason behind using TGG is that this material has excellent transparency properties, and it is highly resistant to laser damage.
When it comes to improving the performance of systems that use light waves, an optical isolator or a PM optical isolator is often a desirable component. However, sometimes, the expensive cost of optical isolators becomes a restriction. Thus, while buying optical isolators, people also look for affordable prices, in addition to their features and specifications.
DK Photonics manufactures PM optical isolators with a broad range of specifications and also caters to custom orders. For any queries related to optical isolators, please connect with us.