Long length uniform illumination light diffusing fiber

A method for forming a light-diffusing element comprising:

• forming a glass core;
• forming a cladding having a thickness of 5 μm to 30 μm on the glass core, the cladding having a lower refractive index than the glass core;
• and
• forming a coating on the cladding, the coating including first scattering centers;
• wherein light having wavelength of 2000 nm has a first scattering intensity, wherein light having a wavelength of 440 nm has a second scattering intensity, and wherein the first scattering intensity is within 5% of the second scattering intensity over a length of at least 50 m of the light-diffusing element.

An illumination system comprising:

• a light source configured to produce light in which a portion of the light from the light source has a wavelength from 440 nm to 2000 nm;
• and
• a light-diffusing element comprising:
• a glass core having a first refractive index and a longitudinal axis defining a length of at least 30 m;
• a cladding surrounding the glass core along the longitudinal axis, the cladding having a second refractive index that is less than the first refractive index of the glass core;
• and
• a coating surrounding the cladding, the coating including first scattering centers;
• wherein the light source is optically coupled to a light-diffusing element;
• wherein light from the light source having wavelength of 2000 nm has a first scattering intensity, wherein light from the light source having a wavelength of 440 nm has a second scattering intensity;
• and
• wherein the first scattering intensity is within 5% of the second scattering intensity over a length of at least 30 m of the light-diffusing element.