Infrared-transmitting, polarization-maintaining optical fiber and method for making
This application relates generally to an optical fiber for the delivery of infrared light where the polarization state of the light entering the fiber is preserved upon exiting the fiber and the related methods for making thereof. The optical fiber has a wavelength between about 0.9 μm and 15 μm, comprises at least one infrared-transmitting glass, and has a polarization-maintaining (PM) transverse cross-sectional structure. The infrared-transmitting, polarization-maintaining (IR-PM) optical fiber has a birefringence greater than 10 −5 and has applications in dual-use technologies including laser power delivery, sensing and imaging.
1 . A method of making an infrared-transmitting, polarization maintaining (IR-PM) optical fiber, comprising:
making a preform with an approximately round cross-sectional shape comprising an approximately round core surrounded by a cladding, wherein the preform comprises an infrared-transmitting, non-silica glass;
compressing the preform to form a compressed preform where both the core and cladding have an approximately elliptical shape;
altering the compressed preform by grinding, polishing, machining, or any combination thereof to make an altered preform with an approximately round cladding; and
drawing the altered preform into a fiber that is approximately round with an approximately elliptical core, wherein the fiber has a birefringence greater than 10 −5 .
2 . The method of claim 1 , wherein the infrared-transmitting, non-silica glass comprises a chalcogenide glass comprising at least one of sulfur, selenium, and tellurium; a glass based on an oxide of at least one of Te, Ge, Pb, and La; a fluoride glass, or any combination thereof.