Method and apparatus for providing amplified radiation

A method for amplifying optical radiation, the method comprising

• providing an optical fiber amplifying system
• one or more first amplifying stages together having an output, each of the one or more first amplifying stages comprising a first active optical fiber, the first active optical fiber being configured to amplify radiation at the first amplified wavelength when pumped with pump radiation of a first amplifying stage pump wavelength;
• and
• one or more first optical pump sources, each configured to output radiation of the first amplifying stage pump wavelength, each operatively coupled to one or more of the first active optical fibers of the first amplifying stages;
• an intermediate stage having an input operatively coupled to the output of the one or more first amplifying stages and an output, the intermediate stage comprising an intermediate active optical fiber having an intermediate stage amplified wavelength and an intermediate stage pump wavelength, the intermediate stage amplified wavelength being substantially the same as the first amplified wavelength;
• a final amplifying stage having an input coupled to the output of the intermediate stage and an output, the final amplifying stage comprising a final active optical fiber, the final active optical fiber being configured to amplify radiation at the first amplified wavelength when pumped with pump radiation of the intermediate stage pump wavelength;
• and
• one or more final optical pump sources together operatively coupled to the final active optical fiber and the intermediate active optical fiber and configured to output radiation of the intermediate stage pump wavelength, the one or more final optical pump sources being configured to be switched together, separately from the one or more first optical pump sources, between a low power state sufficient to render the intermediate active optical fiber substantially non-transmissive to radiation of the first amplified wavelength, and a high power state sufficient to render the intermediate active optical fiber substantially transmissive to radiation of the first amplified wavelength, while maintaining the one or more first optical pump sources are in a high power state;
• and
• providing optical radiation having the first amplified wavelength from the one or more first amplifying stages to the input of the intermediate active optical fiber, while the one or more final optical pump sources are together in a low power state such that the optical radiation is substantially absorbed by the intermediate active optical fiber and such that substantially no optical radiation of the first amplified wavelength is transmitted by the output of the intermediate stage and substantially no optical radiation of the first amplified wavelength is outputted by the output of the final amplifying stage;
• and then
• while continuing to provide optical radiation having the first amplified wavelength from the one or more first amplifying stages, switching the one or more final optical pump sources from the low power state to the high power state, such that the optical radiation of the first amplified wavelength is substantially transmitted by the intermediate active optical fiber and such that substantial optical radiation of the first amplified wavelength is transmitted by the output of the intermediate stage, and such that the output of the final amplifying stage outputs substantial optical power at the first amplified wavelength.

A method for amplifying optical radiation, the method comprising

• providing an optical fiber amplifying system, the optical fiber amplifying system providing amplified optical radiation having a first amplified wavelength, the optical fiber amplifying system comprising
• an optical source having an output, the optical source being configured to provide radiation of the first amplified wavelength;
• an intermediate stage having an input operatively coupled to the output of the optical source and an output, the intermediate stage comprising an intermediate active optical fiber having an intermediate stage amplified wavelength and an intermediate stage pump wavelength, the intermediate stage amplified wavelength being substantially the same as the first amplified wavelength;
• a final amplifying stage having an input coupled to the output of the intermediate stage and an output, the final amplifying stage comprising a final active optical fiber, the final active optical fiber being configured to amplify radiation at the first amplified wavelength when pumped with pump radiation of the intermediate stage pump wavelength;
• and
• one or more final optical pump sources together operatively coupled to the final active optical fiber and the intermediate active optical fiber and configured to output radiation of the intermediate stage pump wavelength;
• and
• providing optical radiation having the first amplified wavelength from the optical source to the input of the intermediate active optical fiber, wherein the one or more final optical pump sources are together in a low power state such that the optical radiation is substantially absorbed by the intermediate active optical fiber and such that substantially no optical radiation of the first amplified wavelength is transmitted by the output of the intermediate stage;
• and then
• while continuing to provide optical radiation having the first amplified wavelength from the optical source, switching the one or more final optical pump sources from the low power state to a high power state, such that the optical radiation of the first amplified wavelength is substantially transmitted by the intermediate active optical fiber and such that substantial optical radiation of the first amplified wavelength is transmitted by the output of the intermediate stage, and such that the output of the final amplifying stage outputs substantial optical power at the first amplified wavelength.