Abstract: A spacecraft or satellite optical transmission apparatus (10) including an optical fiber (11) and at least one optical pump source (14) operatively coupled to provide pump energy to the optical fiber (11), the optical fiber (11) comprising an active trivalent dopant such as erbium and at least one passive trivalent dopant such as lanthanum. A method for transmitting electromagnetic radiation in a high radiation environment is also disclosed.

Abstract: A spacecraft or satellite optical transmission apparatus (10) including an optical fiber (11) and at least one optical pump source (14) operatively coupled to provide pump energy to the optical fiber (11), the optical fiber (11) comprising an active trivalent dopant such as erbium and at least one passive trivalent dopant such as lanthanum. A method for transmitting electromagnetic radiation in a high radiation environment is also disclosed.

Abstract: A polarisation maintaining optical fiber package is described. The fiber comprises a core having a core diameter, a first protective coating layer surrounding the core, the first protective coating layer having a first protective coating inner diameter, a first protective coating outer diameter and a first protective coating thickness between the first protective coating inner diameter and the first protective coating outer diameter, a second protective coating layer surrounding the first protective coating layer, the second protective coating layer having a second protective coating inner diameter and a second protective coating outer diameter, the first protective coating layer comprising a material having a first hardness and the second protective coating layer comprising a material having a second hardness, wherein the thickness of the first protective coating layer is in the range from 6% to 33% of the core diameter.