| 摘要 |
Optical fibres comprised of a halide glass incorporating colour centres, for example fluoride fibres, can behave as a laser or an amplifier when maintained at a low temperature, typically 77 DEG K, and optically pumped. A laser may be comprised by a length of such a fibre (1) wound on a spool (2) and disposed in liquid nitrogen (4), the ends of the fibre are outside of the coolant and associated with input and output mirrors (5,6) which define the extremities of a lasing cavity. An optical pumping signal (7) is provided by a laser (8), for example a Krypton ion laser operating in the visible range. The output of the fibre laser is in the infra-red. Higher gain than with conventional colour centre lasers is achieved due to the longer interaction length and cooling problems are overcome. |
