Evanescent Optics Inc. offers a variable-ratio polarization-maintaining coupler at wavelengths from 0.7 to 2.04 µm. It is tunable over a 0 to 99% coupling range at pre-selected wavelengths. Its extinction ratio is <224 dB with loss of <0.1 dB. Single-mode non-polarization-maintaining versions are also available, and a computer-controlled version is in development. Standard pigtail length is 1 m, with longer lengths available.