Method and apparatus for controlling wavelength and dominant mode in fiber lasers

A method of tuning an output wavelength and dominant mode of a fiber laser disposed in a laser assembly comprising a substrate and a dynamic tuning assembly, the method comprising the steps of:

• a) rough-tuning the laser to an approximate target wavelength and isolating a dominant mode during manufacture, by the steps of:
• a. linearly stretching the laser fiber so as to modify an output wavelength;
• b. axially twisting the laser fiber so as to isolate the dominant mode of oscillation;
• c. monitoring the output wavelength and dominant mode of the fiber laser during stretching and twisting until the desired characteristics of wavelength and dominant mode are reached;
• and
• d. connecting the laser fiber to the laser assembly in its linearly stretched and axially twisted condition;
• and
• b) fine-tuning the laser to a substantially exact wavelength during normal operation, by manipulating the dynamic tuning assembly to modify a length of the laser fiber.

A system for tuning the output wavelength and dominant mode of a fiber laser, comprising:

• a) a moveable bed, configured to receive an elongate fiber laser assembly having a first end and a second end, and a laser fiber secured to the first end thereof, the laser fiber having a long axis;
• b) an axle, having an axis of rotation, configured to securely hold a second end of the laser fiber substantially collinearly with the axis of rotation and beyond the second end of the fiber laser assembly;
• and
• c) an adjustment mechanism, configured to (i) move the bed linearly away from the rotatable axle, so as to linearly stretch the laser fiber between the axle and the secured first end of the fiber, and (ii) rotate the axle to twist the laser fiber along its long axis, so as to allow rough adjustment of an output wavelength and dominant mode of the laser fiber prior to permanently affixing the laser fiber to the second end of the fiber laser assembly.