The IO-D Series "Aspirin Tablet" Isolators are designed for applications requiring a very small Isolator. These Isolators utilize BIG (bismuth-iron-garnet) film as the Faraday rotating material. To retain the very small size, dichroic Very Low Power Polarizers are used. Isolator bodies are Aluminum or Stainless Steel. Stainless steel bodies use approved zero outgassing epoxies for vacuum environment applications. VLP Polarizers absorb the unwanted polarization vector, and are therefore limited in laser power capability. See page IO-3 for polarizer information.

Aspirin Tablet Isolators are set at the OFR factory to the exact laser wavelength for maximum isolation and transmission, and cannot be readjusted thereafter. When ordering, specify the desired peak wavelength, for example, IO-D-780.

The small body size is made possible by the extremely high Verdet constant of the BIG film. For example, film thickness for 45° rotation at 1310 nm is only ~330 µm. In addition, BIG films are characterized by a low saturating magnetic field value, only a few hundred Gauss, thus enabling performance with a small magnet. The final result is an Isolator of small dimensions.