Optical amplifier operating at 1.3 microns useful for telecommunications and based on dysprosium-doped metal chloride host materials

An optical communications system comprising:

• a plurality of optical fiber segments connected in sequence for transmitting an optical signal therethrough, each segment having a length sufficient to substantially attenuate the optical signal;
• an optical amplifier coupling a first of said optical fiber segments to a second of said optical fiber segments, said optical amplifier comprising:
• a laser gain medium comprising a Dy.sup.3+ -doped metal chloride, bromide or iodide host material;
• pumping means to induce laser gain near 1.31 .mu.m in said medium;
• wherein said Dy.sup.3+ dopant exhibits an emission lifetime greater than or about one millisecond at the 1.31 .mu.m emission wavelength.