Abstract: An optical coupler is provided. It has a bundle of multimode fibers with a few-mode fiber in its centre. Such bundle is fused at one end which is the output end for the signal that is transmitted by the few-mode fiber. To make the coupler, this output end of the bundle is aligned and spliced with a large area core double clad fiber while preserving the modal content of the feed-through. A method for making such optical coupler is also provided. It includes the steps of bundling a central few-mode fiber with a plurality of multimode fibers and then fusing one end of such bundle and aligning it and splicing with a large core double clad fiber, while preserving fundamental mode transmission from one to the other.

Abstract: An all-fiber broadband polarization combiner is disclosed based on a Mach-Zehnder (MZ) structure. The entry coupler to the MZ is a polarization pump combiner (PPC) and the exit coupler is a wavelength division multiplexer (WDM) coupler. The two couplers are interconnected with two standard SM fibers which form the arms of the central zone of the MZ. Two polarization maintaining (PM) fibers are spliced to the two input arms of the PPC and are oriented so that polarization X in one PM fiber is orthogonal to polarization Y in the other PM fiber. And the MZ is induced with a phase shift ?? of ? between the two arms of the central zone.

Abstract: The invention provides an optical filter device which is particularly suitable for compensating the gain produced by an erbium doped fiber amplifier due to temperature variations. The device has a tapered fiber filter mounted on a rigid substrate, such as aluminium, in such a manner that the tapered portion of the filter does not come in contact with the substrate. The fiber of the filter is preferably made of silica.

Abstract: This invention provides a method of obtaining accurate measurements of polarization dependent loss and insertion loss during the tests aiming at measuring the polarization properties of optical components. This is achieved by taking into account every polarization disturbance in the line between generation of known states of polarization and the device under test. The method involves computing within a desired range of wavelengths either the transfer matrix of each polarization perturbing element or of all polarization perturbing elements as a whole, and compensating for errors introduced by these polarization perturbing elements.

Abstract: A retaining clip for retaining a strip of optical fiber. The clip includes a mounting base for mounting the clip to a mounting surface. A first spacing leg and a second spacing leg are both attached about their respective first ends to the mounting base. A first retaining leg and a second retaining leg are attached to the first and second spacing legs adjacent their respective second ends. The first and second retaining legs respectively defining a first and a second overlapping segment respectively extending generally inwardly beyond the second and first retaining leg second ends. The first and second overlapping segments are in a generally parallel and spaced relationship relative to each other so as to define an insertion slot therebetween. The insertion slot defining an insertion slot longitudinal axis extending in a generally parallel relationship relative to the spacing between the spacing leg first ends.

Abstract: An all-fiber depolarizer having a linear design includes a directional coupler associated with a polarization combiner. Linear light is pumped into the coupler where its intensity is split in two. Between the coupler and the combiner there is included an optical delay and the polarization of one intensity is made orthogonal to the other, as they enter the polarization combiner. The combiner combines the orthogonal polarizations and the light exits by an output in a depolarized state.

Abstract: An all-fiber Mach-Zehnder interferometer has a central fiber structure in which two single-mode fibers are placed to have a desired path difference and are stabilized in such position by bonding them in certain spots. A coupler is then made on each side of the central fiber structure to produce the Mach-Zehnder effect. The combination of the central fiber structure and of the couplers at each end is mounted on a substrate and packaged to produce the interferometer.

Abstract: A Mach-Zehnder device including an input port, an output port, a substantially achromatic first coupling region optically connected to the input port and a substantially achromatic second coupling region optically connected to the output port. An intermediate region is optically connected to the first and second coupling regions. The intermediate region includes a first intermediate branch and a second intermediate branch. The first intermediate branch defines a phase shifting portion. The phase shifting portion, in turn, defines a phase shifting portion level of birefringence over the length of the phase shifting portion. The phase shifting portion level of birefringence is different that the level of birefringence prevailing over the remainder of the first intermediate branch.

Abstract: An all-fiber optical depolarizer is provided in which polarized light is controllably injected into a polarization beam splitter at a 45° angle. The beam splitter is combined with a loop made of standard non-birefringent fiber through which one of the polarizations split by the beam splitter circulates. The loop has a length greater than the coherence length of the light source. The interaction of the beam splitter and the loop produces incoherent depolarized light at the output transmission port of the beam splitter.

Abstract: A temperature stabilized tapered fiber optic component is produced, such as a fiber optic coupler or a fiber optic filter. In the case of the component such as a coupler, at least two fibers are fused and tapered to achieve a desired taper profile with suitable mechanical and wavelength properties. In the case of a component such as a fiber filter, only one fiber is tapered. Once the component is formed, it is solidly secured to a rigid substrate that produces a mechanical stress such as to compensate for any modal phase shift of the component due to temperature variation. Also, the mechanical phase dependence of the component may be adjusted in relation to the substrate to provide the desired temperature compensating effect. Preferably, both these features are used to achieve the best possible temperature stabilization.

Abstract: A reflectionless termination is provided for an optical fiber that has a core and a cladding. The optical fiber forms part of a device which is mounted in a package and the termination fits inside the package. The termination consists of a short piece of an attenuating fiber connected at the end of the optical fiber and having a doped core which absorbs the light emanating from the core of the optical fiber.