Article comprising an optical fiber laser
AssigneeAT&T Bell Laboratories
InventorsDavid J. DiGiovanni, Victor Mizrahi, John L. Zyskind
Life of this patent
Estimating the term…
Abstract
An article, such as an optical communication system, which includes a laser formed in an optical waveguide or optical fiber having a rare-earth-doped core or core portion. In one embodiment, the optical resonant cavity of the laser is at least partially defined by a distributed Bragg reflector formed in a portion of the core. In contrast to the prior art, the length of the optical resonant cavity is about 5 cm or less.
Claims11
An article which comprises a first laser, the first laser comprising a section of optical fiber including a core and a cladding, wherein:
- a) the fiber section includes at least one wavelength-selective reflector which at least partially defines an optical resonant cavity of a given length;
- b) the reflector has a wavelength of peak reflectivity;
- c) the reflector comprises a pattern of refractive-index modulations extending axially within at least a portion of the fiber core;
- d) at least a portion of the core within the cavity comprises a rare-earth dopant;
- e) the cavity has an optical path length;
- and
- f) the optical path length has a first resonant optical wavelength,
- characterized in that
- g) the given cavity length is about 5 cm or less.
A method for manufacturing an article, comprising the steps of:
- a) providing a length of optical fiber having a rare-earth-doped, photosensitive core;
- b) exposing a first section of the optical fiber core to a stationary interference pattern formed by intersecting beams of electromagnetic radiation of a wavelength which alters a refractive index of the core, such that a repetitive pattern of refractive index modulations is formed in the first section;
- c) substantially without moving the length of optical fiber, shifting the interference pattern axially relative to the length of optical fiber, such that a second core section physically displaced from the first core section is exposed to the interference pattern;
- and
- d) exposing the second core section to the interference pattern, such that a repetitive pattern of refractive index modulations is formed in the second section;
- characterized in that the method further comprises the steps of:
- e) optically pumping the length of optical fiber such that laser radiation is emitted through the first or second core section;
- f) measuring an intensity of the emitted laser radiation;
- g) comparing the measured intensity to a predetermined threshold value;
- and
- h) when the measured intensity is less than the threshold value, optically pumping the length of optical fiber such that laser radiation is emitted through the first or second core section;
- monitoring the intensity of the emitted laser radiation;
- and while pumping and monitoring, exposing a third core section, intermediate the first and second core sections, to refractive-index-altering radiation for sufficient duration to raise the emitted intensity being monitored to at least the threshold value.
Dependencies are inferred from the claim text.