A large
diameter optical
waveguide,
grating, and
laser includes a
waveguide 10 having at least one core 12 surrounded by a cladding 14, the core propagating light in substantially a few transverse spatial
modes; and having an outer
waveguide dimension d2 of said waveguide being greater than about 0.3 mm. At least one Bragg
grating 16 may be impressed in the waveguide 10. The waveguide 10 may be axially compressed which causes the length L of the waveguide 10 to decrease without buckling. The waveguide 10 may be used for any application where a waveguide needs to be compression tuned, e.g., compression-tuned
fiber gratings and lasers or other applications. Also, the waveguide 10 exhibits lower
mode coupling from the core 12 to the cladding 14 and allows for higher
optical power to be used when writing gratings 16 without damaging the waveguide 10. The shape of the waveguide 10 may have other geometries (e.g., a “dogbone” shape) and / or more than one
grating or pair of gratings may be used and more than one core may be used. The core and / or cladding 12,14 may be doped with a rare-earth
dopant and / or may be photosensitive. At least a portion of the core 12 may be doped between a pair of gratings 50,52 to form a
fiber laser or the grating 16 or may be constructed as a tunable DFB
fiber laser or an interactive
fiber laser within the waveguide 10. The waveguide may resemble a short “block” or a longer “
cane” type, depending on the application and dimensions used.