Abstract: A hermetically sealed package for an electro-optical device has a two-part casing with a fiber feedthrough. The feedthrough defines a gap and is assembled using fastening means, typically bolts or screws, that are placed such that the walls of the feedthrough are prestressed before a molten solder is injected into the feedthrough to seal the casing. The material of the bolts has a greater coefficient of thermal expansion (CTE) than the CTE of the casing, whereby the mismatching between the CTE of the casing and the solder is at least partly compensated.

Abstract: A method and device is disclosed for dispersion compensation of an optical signal having periodic dispersion within a multi-channels system. For example interleaved optical channels often exhibit dispersion having a characteristic that is repeated in adjacent channels. By providing a periodic device in the form of a multi-cavity GT etalon having a free-spectral range that corresponds to the channel spacing the dispersion in the interleaved signal can be lessened and practically obviated or balanced to a desired level. This invention provides a device and method to achieve that end.

Abstract: The invention provides a cylindrical polarization diversity circuit for narrowing the numerical aperture of an incoming beam of light in a direction perpendicular to the dispersion direction and without affecting the numerical aperture of the incoming beam of light in the direction of dispersion. A cylindrical lens is employed to provide an output beam having an elliptical cross-section. The output beam is collimated in one direction and diverging in a direction perpendicular thereto. A birefringent element having its walk-off direction oriented such that it coincides with the collimated beam direction separates the output beam into two orthogonally polarized sub-beams having an elliptical cross-section. The sub-beams are substantially non-overlapping. Advantageously, a halfwave plate is provided so as to make the polarization states of both sub-beams substantially parallel.

Abstract: The instant invention provides a vibration insensitive method of precisely polishing an object. The method includes the steps of providing an object to be polished, applying a conductive material to a non-electrical current conductive surface of the object, removing a portion of the object and the conductive material through polishing, and measuring an electric current flowing through the conductive material to monitor a progress of the polishing. Advantageously, the method does not require the polishing process to be interrupted to monitor the progress of the polishing. In fact, since the progress is measured as a function of resistance/electrical current, the progress is measured with an accuracy and precision related to each individual turn of a polishing pad. Advantageously, the instant method is remarkably vibration insensitive and is practical for the simultaneous, automatic, and precise, polishing of monolithic objects.

Abstract: In order to reduce amplified spontaneous emission noise in the output signal of an amplifier of the kind in which amplification introduces amplified spontaneous emission, for example an erbium-doped fiber amplifier, the amplified signal is filtered using a loop mirror filter. The loop mirror filter may comprise a 3-dB fiber coupler with a loop of linear active fiber connected between two of its ports. The amplified signal and the filtered signal may be applied to, and extracted from, one of its other ports, conveniently by way of a circulator.

Abstract: The invention provides an optical switch having an input port for launching a beam of light into the optical switch, at least two output ports, each output port for selectively receiving a beam of light, an ATO element having optical power for providing an angle to offset transformation, and beam directing means for selectively directing a beam of light from the input port to a selected one of the at least two output ports along an optical path via the ATO element. The ATO element is a lens or a mirror.

Abstract: A method and system are provided for measuring a characteristic of a lens. By directing light to a lens, and receiving reflected light from a opposite end faces of the lens on an image plane, a determination from the focused spots on the image plane can be made as to a characteristic of the lens, such as its focal length.

Abstract: An optical switching device for controlling an optical signal is disclosed. The optical switching device is in the form of an optical loop, the loop having two ports for launching or receiving light. A switching element is interposed within the loop for selectively launching light to one of the two ports. The switching element has a polarization rotating element for rotating the polarization of light incident thereon and a wavelength dependent filter disposed to bypass the polarization rotating element or direct a signal propagating within the loop through the polarization rotating element in dependence upon wavelength.

Abstract: A method and apparatus for aligning optical components effectively locks pairs of ports in alignment, while simultaneously allowing further alignment of the same or a different pair of ports. The effective locking of pairs of ports is achieved by providing a virtual pivot point close to the ports, via a relatively fast compensating movement. In the preferred embodiment, the relatively fast compensating movement is provided by a mechanism based on a electromagnet. Since the ports are locked, i.e., are always aligned with being affected by any other activities, the instant method and apparatus for alignment is highly suitable for automation.

Abstract: Apparatus and method for catheterized delivery or infusion of medication and anaesthesia are disclosed. The perforating catheter is first used to perforate the periodontal ligament and/or the cortical plate of bone tissue, and is then left in place and used as a catheter for insertion of a hypodermic needle of smaller gauge to deliver medication or anaesthesia to a target area. The perforator is a bevelled needle for drilling into the ligament or bone tissue. For drilling, the device comprises an adaptor which transmits the rotational movement from a dental hand piece to the bevelled needle. A cap is also included for protecting the bevelled needle during storage of the device. The adaptor may have a rod which extends axially into the bevelled needle when the device is assembled for drilling. The rod is used to prevent the debris resulting from drilling from blocking the passage in the bevelled needle.

Abstract: The invention provides a fast variable optical attenuator including a reflective membrane that serves as a varifocal mirror. Electrostatic deflection of the mirror defocuses the optical system and attenuates an optical signal launched to the mirror from an input port to an output port. Since the mirror is generally limited to deflections less than 1 micron, fast attenuation within a small (<5 dB) dynamic range is achieved. The dynamic range is improved by combining the fast attenuator with a slower attenuator. In the preferred embodiment, the slow and fast attenuator are not coupled via optical waveguides, but rather are optically coupled via free space or are integrated in the same device. Advantageously, this compact arrangement reduces the excess loss associated with optical fiber coupling and lowers packaging costs.

Abstract: A system and method for resolving polarization mode dispersion (PMD) in a span of optical fiber is described. The method involves three main stages: (1) launch two co-polarized optical signals to generate respective four-wave mixing product fields at the Stokes wavelength &lgr;S or the anti-Stokes wavelength &lgr;A sequentially in each part of the fiber to calculate chromatic dispersion; (2) repeatedly launch two optical signals at various states of polarization (SOP) using methods of stage (1) to calculate overall dispersion (i.e., a combination of chromatic dispersion and PMD); and (3) resolve from the overall dispersion calculated at stage (2) the PMD based on the known chromatic dispersion calculated at stage (1). In an ideal case, the PMD can be calculated from two separate measurements at different co-polarized states of polarization, where group velocity is calculated from a measured dispersion map, as a function of wavelength, at the SOPs and the difference is calculated to resolve PMD.

Abstract: An optical switch is disclosed which operates as binary or digital switch. Two glass waveguides are arranged in an X-like pattern such that they approach each other at a waist region without crossing over one another. A polymer region contacts both waveguides at this waist region and has a refractive index that can be changed more than that of the adjacent glass by applying heat. The refractive index of the polymer can be varied from an index which is same as the glass waveguides; to be less than that of the glass in which case the polymer acts as a cladding. When the index of the polymer is lower than that of the glass through the application of heat, light launched into one of the waveguides continues along the waveguide via total internal reflection and no light crosses the glass polymer boundary.

Abstract: Tuning to maximize the isolation provided by an optical isolator to one of a predetermined plurality of wavelengths is achieved by tilting the isolator with respect to an input beam of light. Further tuning to a peak response for a given wavelength is achieved by rotation of the isolator about its longitudinal axis while or after tilting. In the manufacture of the isolator a test beam is launched into an output port end directed toward the input end. Tilting, or tiling and rotating is initiated and light at the input end is measured while tilting/rotating. When the position is determined where the minimal amount of light is measured, the optical elements are glued or secured in place, thereby providing a way to alter the response of an isolator for a given wavelength of input light.

Abstract: A package for an optical device comprising two mating sections, each section including a rigid outer protective shell and a resilient inner body. The package is easily clamped together using snap clips, which are integral with the rigid outer protective shells. Preferably, strain relief is provided integrated on each end of the resilient bodies.

Abstract: An optical coupling device and method is disclosed, wherein two lenses having a non-unitary configuration are positioned between a plurality of input ports and a plurality of output ports having different center-to-center distances. More specifically, the spacing d1 between input ports is fixed and is different in magnitude from the fixed spacing d2 between output ports. Preferably, the two lenses have a common axis and are separated by a distance d3, which is selected in dependence upon the known and fixed spacings, d1 and d2. Advantageously, the disclosed coupling device provides a simple and economical apparatus and method for coupling light between a first plurality of ports having a fixed distance therebetween to a second plurality of ports having a different fixed distance therebetween.

Abstract: The invention provides an optical deflection switch having reduced insertion loss. The device includes a switching block having a reflective surface and a transmissive face, a second block having a first and a second face, and a switch for selectively switching the device from a first switching state to a second switching state. The optical deflection switch of the present invention provides a switch in which a deflected beam is directed to one of a plurality of output ports at normal incidence and hence the insertion loss of the optical deflection switch is reduced. The output beam in the first switching state is parallel to the output beam in the second switching state.

Abstract: A wavelength demultiplexer having a substantially flat output response within its passband is disclosed. The demultiplexer comprises a first wavelength demultiplexer optically coupled to a second wavelength demultiplexer. The first wavelength demultiplexer has a free spectral range approximately equal to channel spacing of the second wavelength demultiplexer thereby providing the substantially flat output response within the passband. The first wavelength demultiplexer is an MMI-phasar having a tapered MMI coupler.

Abstract: An optical switch is disclosed having 4-ports. The switch consists of a first GRIN lens having 2 ports adjacent its outwardly facing end face. A second GRIN lens is disposed to receive light from the first GRIN lens and has two ports adjacent its outer end face. In a first state, a first port from the first GRIN lens couples light with a first output port of the second GRIN lens. In a second state, a movable optical element in the form of a light transmissive wedge having a reflective surface, is disposed in the path between first and second GRIN lens, providing a connection between a port of the first GRIN lens and a second port of the second GRIN lens. In a third connect state, the reflective surface of the wedge connects a port of the first GRIN lens and an output port in the same first GRIN lens. Hence an N×M optical switch is disclosed.

Abstract: An M×N optical switch in which the focal lengths of the collimating lenses are adjusted so that the waists of the Gaussian beams exiting the collimating lenses are focused on reflecting elements, which are positioned along a diagonal of the array of reflecting elements. This arrangement increases the number of beams that are symmetrical about the waist position, which increases the coupling efficiency. The best possible arrangement occurs when all of the waists are equal in diameter, thereby ensuring that for every output port the distances from the waists to the focusing lens are identical.