Abstract: Broadband in-line gratings in optical waveguides are disclosed. The gratings have a bandwidth of at least 2 nm (preferably at least 4 nm) and a peak reflectivity of at least 70% (preferably at least 90%). Exemplarily, such gratings can be formed in H.sub.2 -treated Si-based fibers that support a normalized index change of at least 10.sup.-3. Gratings according to the invention can be used, for instance, to form pump radiation reflectors in an optical fiber communication system with Er-doped fiber amplifiers, or to flatten the amplifier gain curve. The gratings can be of the blazed or non-blazed type.

Abstract: The invention involves a method for making Bragg gratings in glass optical fibers, or other glass optical waveguides, which is relatively insensitive to perturbations in the actinic light used for processing. This method is suitable for mass production and lends itself well to the manufacturing environment. The invention method involves first providing an optical phase grating. An interference pattern is generated by impinging a single light beam on the grating. The optical waveguide to be processed is exposed to this interference pattern, leading to the formation of a Bragg grating in the waveguide.

Abstract: An improved method for forming a Bragg grating in a photosensitive, optical waveguiding medium by exposure to an interference pattern formed by overlapping beams of actinic radiation. When Bragg gratings are formed according to methods of the prior art, these gratings tend to exhibit reflectivity spectra having, in addition to a central peak, a generally undesirable series of subsidiary peaks. These subsidiary peaks are caused by a wave interference effect. The inventive method modifies or eliminates the subsidiary peaks by spatially modulating the average refractive index of the grating, or by spatially modulating the grating period.

Abstract: An optical pulse source includes a semiconductor diode laser, an external optical cavity, and a source of a modulated drive current such that the laser can be actively mode-locked. The external cavity includes an optical fiber and a distributed Bragg reflector. In preferred embodiments, the optical pulse source can produce pulses having a time-bandwidth product within about 20% of the transform limit, such that soliton pulses can be transmitted.

Abstract: Unexpectedly large normalized refractive index changes (.DELTA.>10.sup.-5, but possibly even larger than 10.sup.-3) can be obtained in oxide glass, e.g., high-silica glass, by a treatment that comprises exposing at least a portion of the glass at a temperature of at most 250.degree. C. to H.sub.2 or D.sub.2 (partial H.sub.2 or D.sub.2 pressure greater than 1 atmosphere), and irradiating at least a part of the exposed portion with actinic (typically UV) radiation. The method can be used to make optical components that comprise a region (or regions) of raised refractive index, e.g., an in-line refractive index grating in an optical waveguide, a planar optical waveguide, or a phase grating.

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.

Abstract: Unexpectedly large normalized refractive index changes (.DELTA.>10.sup.-5, but possibly even larger than 10.sup.-3) can be obtained in SiO.sub.2 -based optical waveguides (fiber or planar waveguides) by a treatment that comprises exposing at least a portion of the waveguide at a temperature of at most 250.degree. C. to H.sub.2 (partial pressure greater than 1 atmosphere), and irradiating at least a part of the exposed portion with actinic (typically UV) radiation.

Abstract: Broadband in-line gratings in optical waveguides are disclosed. The gratings have a bandwidth of at least 2 nm (preferably at least 4 nm) and a peak reflectivity of at least 70% (preferably at least 90%). Exemplarily, such gratings can be formed in H.sub.2 -treated Si-based fibers that support a normalized index change of at least 10.sup.-3. Gratings according to the invention can be used, for instance, to form pump radiation reflectors in an optical fiber communication system with Er-doped fiber amplifiers.