IO-K-2000 In Stock

The IO-K-2000 from Thorlabs is a high-quality fiber isolator that utilizes special protections that are essential to preventing unwanted back reflections and signals from negatively affecting the light sources- which could result in optical damage or intensity noise. This device is an essential tool for ensuring accurate and stable measurements in a wide range of research and industrial applications. The IO-K-2000 is a polarization-independent isolator that is compatible with single mode (SM) fibers. The isolator is a device that enables light to pass through it in one direction only. It does this via a Faraday rotator, two polarizers, a half-wave retarder and collimating lenses. This helps ensure that light is only transmitted forward and any reverse propagation of beams of light will be blocked or scattered by the device. The main body of the IO-K-2000 isolator contains the Faraday rotator, polarizers, and retarder. The outer aluminum sleeves protect the input and output ports containing the collimating lens and fiber ferrule. The IO-K-2000 also comes with an arrow engraved on the body indicating the transmission direction.

The IO-K-2000 is mounted on a baseplate with two 4-40 (M3) counterbored slots for securing the unit to a breadboard or optical table. This base may be removed by the user if desired, providing greater flexibility in the setup. The IO-K-2000 isolator is capable of handling a wide range of laser light inputs. Laser light enters the IO-K-2000 isolator via the input single mode fiber. A lens collimates the light and splits it as it goes through a birefringent beam displacer polarizer. The light then enters the rotator, which rotates its plane of polarization 45°. It then passes through a retarder and second displacer polarizer. Finally, it exits via another collimating lens coupling into output fiber.

When operating in reverse mode, some random beam reflections will be reflected back through the fiber towards the laser. This feedback enters the IO-K-2000 isolator and is split by the output beam displacer. The two beams are rotated 45 degrees by the waveplate and another 45 degrees by the Faraday rotator. As a result, the two beams are now oriented 90 degrees as compared to the forward beams and walk off a second time instead of being recombined. These beams do not couple into the input fiber and are absorbed inside the isolator housing. As a result, the laser is now isolated from downstream reflections.