Patent ID: 7366378

Claim:
An ultrafast laser machining system to form a diffractive structure in an optical fiber, comprising: a pulsed laser source for generating a plurality of pulses of laser light, each pulse of laser light having a pulse energy equal to a machining energy level and a predetermined pulse width less than about 1 ns; optics aligned in a beam path of the plurality of pulses of laser light to focus the plurality of pulses to a beam spot; a fiber mount to hold and controllably move the optical fiber such that the beam spot is aligned to a target region within the optical fiber, the fiber mount including; a first linear translation stage to move the optical fiber in a Z direction substantially parallel to a direction of propagation of the plurality of pulses of laser light at the beam spot; a second linear translation stage to move the optical fiber in a Y direction substantially perpendicular to the direction of propagation of the plurality of pulses of laser light at the beam spot and substantially parallel to the longitudinal axis of the optical fiber at the beam spot; and a fiber holder coupled to the two linear translation stages to hold the optical fiber; and an imaging system to image the target region of the held optical fiber; wherein the pulsed laser source includes: a pulsed laser oscillator to produce the plurality of pulses of laser light having a predetermined initial pulse energy; and a variable attenuator aligned in the beam path of the plurality of pulses of laser light to control the pulse energy of the plurality of pulses at the machining energy level.