Optical isolator
OFR
Thorlabs
Isolation Values from 30 to 47 dB Depending on Model
Wavelength Ranges from 780 to 2050 nm
Polarization Independent and Dependent Versions
Available with or without Connectors
Fiber Types
Polarization-Independent Isolators Use SM FIber
Polarization-Dependent Isolators Use PM FIber
High Power Fiber Isolators are Built with a Specialized Fiber End Face Process to Increase the Power Handling Capability
Fiber isolators protect laser sources from back reflections and signals that can cause instabilities and damage to fiber coupled laser sources. An isolator is an optical device that allows light propogating in the forward dirction to be transmitted while absorbing or displacing light propogating in the reverse directions. Fiber isolators are available in both polarization-dependent and polarization-independent models throughout the 780 to 1550 nm wavelength range.
When choosing an isolator, operating power and wavelength are the two most important factors. Isolators for use below 3 W and with wavelengths longer than 1250 nm use a Bismuth Iron Garnet (BIG) rotator. For shorter wavelengths and the same power levels, Terbium-Gallium Garnet (TGG) rotators are typically employed. These rotators have a much lower Verdet constant than BIG rotators and require the use of magnets taht are orders of magnitude larger. High-power isolators, which are designed for maximum powers of 50 W (depending on model), use non-absorptive crystal polarizers as well as crystal Faraday rotators. Thorlabs' Faraday Rotator crystal of choice is TGG (terbium-gallium-garnet).
Note: Units with PM fiber use PANDA type PM fiber with a core-cladding-coating size of 7/125/400 µm. The rest of our isolators have an outer coating on the fiber of 250 µm.
