Abstract: An optical assembly is provided that can mitigate thermal damage that could otherwise occur in the region near where the optical fiber emerges from a high-power optical device package. The optical assembly includes an optical medium to guide stray light, along the fiber axis but substantially outside of the fiber core, from the interior to the exterior of a housing. The assembly further includes a transition region external to the housing, where at least one optical mode guided by the optical medium transitions to at least one optical mode confined by a polymer coating as a guided mode of the cladding. In embodiments, the optical medium is provided by the fiber cladding together with overlying materials of relatively low refractive index that help to confine the stray light within the cladding.

Abstract: An optical assembly is provided that can mitigate thermal damage that could otherwise occur in the region near where the optical fiber emerges from a high-power optical device package. The optical assembly includes an optical medium to guide stray light, along the fiber axis but substantially outside of the fiber core, from the interior to the exterior of a housing. The assembly further includes a transition region external to the housing, where at least one optical mode guided by the optical medium transitions to at least one optical mode confined by a polymer coating as a guided mode of the cladding. In embodiments, the optical medium is provided by the fiber cladding together with overlying materials of relatively low refractive index that help to confine the stray light within the cladding.

Abstract: The present invention provides an apparatus comprising a passive optical transmission fiber. The passive optical transmission fiber comprises a passive glass fiber core, a glass optical inner cladding surrounding the core and a glass optical outer cladding surrounding the inner cladding. The inner cladding has a lower index of refraction than the passive glass fiber core and the outer cladding has a lower index of refraction than the inner cladding. The passive optical transmission fiber also comprises a second optical segment coupled to the optical fiber. The second optical segment is configured to dissipate light in the inner cladding.

Abstract: In accordance with the invention, an optical waveguide comprising a longitudinally extending core housing an optical grating and a cladding layer peripherally surrounding the core, is provided with an outer surface of the cladding layer having one or more perturbations. Each perturbation has a height with respect to the core that varies by at least 0.1 times a Bragg wavelength of the grating over the surface of the perturbation and covers an extent of the outer surface whose linear dimensions are less than 1 cm. The perturbations suppress cladding mode spectra and reduce short wavelength cladding mode loss.

Abstract: In accordance with the invention, an optical fiber array comprises a substrate providing a planar array of optical fibers. The optical fibers are parallel to an array axis, but the fiber ends present smooth, polished surfaces angled from the array axis to minimize return loss of light directed along the axis. Three embodiments are described. The first is a series of 1×n strip arrays each mounted at an angle to the array axis to form a saw tooth configuration faceplate. The holes in each strip are also angled to compensate for the angled mount. A second embodiment uses an angled planar faceplate having tapered holes. A third embodiment uses an angled faceplate planar with double-tapered holes to obtain the angled end surfaces. In each embodiment, the fiber ends are substantially coplanar with the faceplate surface but the ends are angled with respect to the array axis.

Abstract: A non-linear temperature compensating device for optical fiber gratings includes first and second expansion members having different coefficients of thermal expansion. The expansion members are elongated in a direction parallel to the fiber grating and levers are secured to both ends of the expansion members. Each lever has a first end flexibly secured to a respective end of the first expansion member and a middle portion flexibly secured to a respective end of the second expansion member. The other end of each lever is secured to a respective end of the fiber grating through a respective quartz block. The dimensions of the expansion members and the quartz blocks, as well as the materials of the expansion members, are selected to achieve a non-linear temperature response which substantially compensates the non-linear temperature response of the fiber grating. The expansion members, the levers and the fiber grating all lie substantially in a single plane.

Abstract: A multi-wavelength Raman radiation source is disclosed. The source receives pump radiation at a given wavelength, e.g., 1100 nm, and has outputs at two or more longer wavelengths, e.g., 1450 nm and 1480 nm. The cascaded Raman resonator comprises, for each desired output wavelength, an optical cavity formed by a high reflectivity grating and a low reflectivity grating, with both having the same center wavelength, equal to the desired output wavelength. Multi-wavelength Raman radiation sources have a variety of applications, e.g., they can advantageously be used in a remotely pumped optical fiber communication system.

Abstract: A temperature compensating device for optical fiber gratings includes first and second expansion members having different coefficients of thermal expansion. The expansion members are elongated in a direction parallel to the fiber grating and levers are secured to both ends of the expansion members. Each lever has a first end flexibly secured to a respective end of the first expansion member and a middle portion flexibly secured to a respective end of the second expansion member. The other end of each lever is secured to a respective end of the fiber grating. The expansion members, the levers and the fiber grating all lie substantially in a single plane. There is also disclosed a package for holding four of the temperature compensating devices in two rows of two devices each, with their fiber gratings adjacent each other so that when viewed in a plane orthogonally to the longitudinal axes of the fiber gratings, the fiber gratings are each at a respective corner of a rectangle.

Abstract: A temperature compensated optical fiber grating device comprises a longitudinally extending optical fiber grating having a length and a packaging assembly for the grating comprising a first longitudinally extending body of material having a first coefficient of thermal expansion (CTE) and second and third longitudinally extending bodies of material having CTE's lower than the first CTE. The three bodies are mechanically attached at alternate ends to form a composite structure having an effective negative CTE between two ends to which the grating is attached. The resulting grating device can be made in compact form having an overall length less than 30% more than the grating (and preferably less than 10%) and can reduce the temperature dependent wavelength change in the grating to less than 0.2 nm/100.degree. C. and preferably less than 0.05 nm/100.degree. C. In a preferred embodiment, the packaging bodies include a cylinder enclosing the grating.

Abstract: The specification describes an optical fiber grating package with means for controllably adjusting the strain in the optical fiber grating count. The package is provided with two threaded members with different thread counts so that when both members are simultaneously turned axial displacement results, and the magnitude of the displacement is determined by the difference between the axial displacement of the two threads.

Abstract: A method for preparing optical fibers for an evanescent field coupler by forming a groove along a top surface of a substrate block, wherein the groove is formed shallower than the diameter of a stripped fiber. An optical fiber is positioned in the groove, wherein a center portion of the optical fiber is stripped of its coating. The optical fiber is glued in the groove, then polished to remove a portion of its cladding to form a coupling region, while not polishing the top surface of the substrate block. An optical signal is applied to an end of the optical fiber while loss of the optical signal is measured at the coupling region. Polishing and monitoring are repeated until a desired loss value is reached. The coupler can be added to an operating optical communication system.

Abstract: A freeze device for an elongated element includes a pressure vessel disposed about at least a part of the element and a freeze seal between the part of the elongated element and the pressure vessel. The freeze seal includes a frozen material exerting a force inwardly against the part of the element and outwardly against the pressure vessel by virtue of having been frozen in situ such that the frozen material thereby seals the elongated element to the pressure vessel.

Abstract: An evanescent field coupler comprising a coupler holder, a first optical fiber mounted in a first substrate block, and a second optical fiber mounted in a second substrate block. The first substrate block is compliantly mounted to the holder. Means are included for positioning the substrate blocks with respect to the other for switching and adjustment of the coupling ratio. The compliant mount elastically deforms during switching and/or alignment to facilitate accurate, repeatable switching, while maintaining the desired coupling ratio between the optical fibers.