Patent ID: 7251260

Claim:
Optical apparatus comprising: a diode-laser emitter arranged to emit an output beam along a propagation axis, said diode-laser having fast axis, and a slow axis perpendicular to each other and perpendicular to said propagation axis, said beam having a first divergence in said fast axis and a second divergence in said slow axis, said second divergence being less than said first divergence, and said diode-laser having a gain-bandwidth; a lens disposed on said propagation axis of said diode-laser, said lens configured and aligned with said diode-laser such that said output beam is transmitted by said lens collimated in said fast axis and with said slow axis divergence unchanged; an optical fiber arranged to receive said transmitted output beam, said optical fiber having a core surrounded by a first cladding, said first cladding being surrounded by a second cladding, said first cladding having a lower refractive index than that of said core, and said second cladding having a lower refractive index than that of said first cladding; and said core including a wavelength-selective Bragg grating and having a first numerical aperture dependent on the difference between the refractive index of said core and the refractive index of said first cladding, said first numerical aperture being about 0.06 or less and wherein said diode-laser has a gain bandwidth and said Bragg Grating has a reflection bandwidth less than said gain bandwidth and has a peak reflectivity within said gain bandwidth whereby the diode-laser light reflected by the Bragg Grating back into the diode-laser stabilizes the wavelength output of the diode-laser.