Abstract: An AC power line protection device which includes a protection circuit which guards against miswiring also has an indicator lamp which lights when the device is in the tripped condition and turns off when the device is reset. If the device is miswired after having been wired properly, the indicator lamp does not light when the device is tripped, and so provides a supplemental indication of miswiring. The protection circuit is powered from the hot line bus bar. The indicator lamp is also powered via the hot line bus bar of the interrupting contacts to meet safety standards.

Abstract: An arc fault protection device uses two detection levels for detecting both parallel and series arc faults. When a sensed load current is below a predetermined level, a first set of characteristics indicative of a series arc fault are compared to a sensed di/dt signal. When the sensed load current exceeds the predetermined level, a second set of characteristics indicative of a parallel arc fault are compared to the sensed di/dt signal. This approach allows more time to evaluate a potential series arc fault than is permitted when evaluating a potential parallel arc fault.

Abstract: A non-blocking N×N cross-connect is provided that has an array of liquid crystal (LC) switches in a grid of planar optical waveguides within a light optical circuit (LOC). LC filled trenches are used in a planar optical waveguide and each trench provides the functionality of a waveguide polarization splitter, a transverse electric (TE) switch cross point, a transverse magnetic (TM) switch cross point, or a waveguide polarization combiner. By combining these elements, a cross-connect system is fabricated.

Abstract: An apparatus for measuring polarization dependent loss is disclosed featuring several fiber optic couplers combined in tandem and oriented such that the PDL noise of the measurement system is reduced to a negligible level. By matching the PDLs of the couplers and vectorally subtracting opposite phases of polarization, the PDL of the measurement system is virtually eliminated. Thus, the PDL noise floor is lowered to near zero and the PDL of the optical device-under-test (DUT) can be accurately measured. The system is relatively inexpensive to implement and offers needed versatility because it measures the PDL of optical devices that operate in a reflection mode or in a forward transmission mode. Thus, it provides one PDL measurement solution for both types of devices.

Abstract: A fused coupler optical switch (FCOS) of the present invention is an electrically switchable device that functions as a latching bi-directional optical cross bar switch with a first and a fourth optical ports at a first end, and, a second and third ports at a second end of the coupler, where a magnetic sleeve surrounds the second end of the coupler. A first stop block maintains the coupler in a first mechanical position and a second stop block maintains the coupler in a second mechanical position, where the first and second stop blocks are V-grooved stop blocks. In the first position, the first port is optically connected with the third port and the fourth port is connected with the second port. In the second position, the first port is optically connected with the second port and the fourth port is connected with the third port. The inventive optical switch may include a sensor element such as a Hall element for detecting the state of the optical switch.

Abstract: The present invention relates to a method for terminating the end of an optical fiber. In particular the present invention relates to a method for forming a low reflectance termination on an end of an optical fiber. The method including the step of tensioning the optical fiber between two spaced apart points thereon. The method further including the step of moving a ball termination torch from a given location in a given direction with respect to the fiber such that a potion of the flame therefrom intercepts the fiber and severs the fiber into two pieces each having a tapered end. The method further includes the steps of retracting at least one of the tapered ends a predetermined distance in a direction away from the other of the tapered ends and continuing to move the torch such that the flame heats the at least one of the tapered ends to cause it to become shortened.

Abstract: An automated optical chip holder for use in a pigtailing system precisely positions an optical chip at a predetermined location in three-dimensional space to align the optical chip within the pigtailing system. An adjustable chuck assembly is driven by a stepper motor under PLC control to position optical chip. After alignment, the optical chip is clamped by the adjustable chuck assembly during the pigtailing process to prevent the optical chip from moving out of alignment. This significantly reduces the occurrence of glue-joint failure and misalignment due to retraction stress. The clamp is fabricated using soft resilient materials at the point of contact with the chip. Thus, uniform pressure is exerted on the chip, micro-vibrations are absorbed, damage to the chip is reduced, and the necessity of precision motion control of the chuck assembly is avoided.

Abstract: A reconfigurable bi-directional wavelength selective switch is disclosed. It has an optical system that is symmetric about a polarization modulator. The symmetric optical system consists of an input birefringent optical system and output birefringent optical system disposed around polarization modulator. The optical system delivers the wavelength channels that are to be switched as a superimposed wavelength channel incident the polarization modulator. As a result, crosstalk is reduced below −35 dB and greater optical performance is achieved.

Abstract: The present invention provides environmentally stable interferometric and lattice devices that exhibit low excess loss and polarization dependent loss. The interferometric and lattice devices of the present invention are inexpensive and simple to make. The modal noise at the splices between the device pigtails and the system fiber is minimized or eliminated. The present invention is an optical device for filtering a light signal. The optical device has a tunable spectral response. The optical device includes an optical fiber having a core region and a cladding with refractive index n2. The first core region includes a core having a refractive index n1 and a first fiber coupling regulator integral with the first optical fiber. The first fiber coupling regulator couples the light signal between a first optical path and second optical path and substantially prevents the light signal from coupling into a third optical path.

Abstract: A tapered optical fiber coupler includes a first fiber with a core (11) and a cladding (12) and a second fiber with a core (21), an inner cladding (22) and an outer cladding (23). In the stretched, coupling regions of the device, the coupling regions (44, 50) of the fibers form of coupling region waveguides with dispersion curves crossing one another at a preselected operating wavelength. The one or more claddings of each fiber has a monotonic decreasing refractive index distribution, and the refractive index distributions of the claddings (12, 22, 23) are different from one another. Coupling of light from one another occurs only in the narrow band of wavelengths surrounding the operating wavelengths. The outside diameters and core diameters of the fibers may be identical to one another and identical to those of standard optical fibers. Thus, the device can be connected in an optical system.

Abstract: An asymmetric thermo-optical switch uses materials having different dn/dT coefficients. A first waveguide is constructed on a planar substrate using a material that has a first dn/dT coefficient. A second waveguide is constructed on the planar substrate using a second material that has a second dn/dT coefficient. In a first embodiment, a coupling region is formed between the first and second waveguides. An index-adjusting switch element is deposited on a first side of the device over the coupling region to control the proportion of light coupled between the waveguides. In a second embodiment, a splitting region is formed by connecting the second waveguide to the first waveguide, at a middle portion of the first waveguide. An index-adjusting switch element is deposited on a first side of the device over the splitting region to control the proportion of light split between the waveguides.

Abstract: A fiber optic sensor for simultaneously and independently measuring temperature and axial stress. The fiber sensor includes a pair of polarization-maintaining fibers that have known strain and temperature response curves. Each fiber has a plurality of fiber segments in which the elliptical cores are rotated 45° relative to the preceding core segment. Thus, the phase shift induced by temperature or stress in each of the fibers is detected, and the strain and temperature are derived from the detected phase shift. The fiber optic sensor is capable of dual operation. As both a temperature sensor and an axial stress sensor.

Abstract: A wideband polarization splitter and combiner is fabricated using either fiber coupler technology or planar coupler technology. The device splits or combines wideband light signals without losing a substantial amount of spectral information. An antipodal phase generator is used to split a randomly polarized light signal into relatively wideband polarization components for use by polarization sensitive devices. The optical device is fabricated using polarization preserving fibers or waveguides, but it is intended for use in systems employing non-polarization-preserving fibers. The polarization splitter/combiner is also used as the basis for an isolator/circulator and a polarization controller. The polarization controller converts a randomly polarized light signal into a signal having a known and definite state of polarization.

Abstract: A fiber coupled variable optical attenuator includes an optical fiber coupler mounted through a low modulus material bushing into a protective enclosure with one end clamped and another end free. The free end of the coupler is deflected by a motorized mechanism. The mechanism includes an electric step motor, a shaft providing eccentric motion, and a support/deflection component connected with the coupler in a kinematic chain providing lateral deflection of the coupler's free end. The structural and material parameters of the kinematic chain members are established to satisfy conditions of thermal compensation for the enclosure enveloping this chain. The free end of the coupler is equipped with a sleeve having a spherical polished surface positioned in contact with the deflection component. The enclosure is equipped with a thermal-compensating device positioned in series between the enclosure and optical fibers.

Abstract: An N-port optical wavelength division multiplexer and demultiplexer includes two evanescent wave couplers connected by N optical paths. Each of the optical paths includes wavelength-selecting elements that are used to select specific wavelengths of light. Light signals composed of N wavelengths of light introduced to an exterior port in one of the couplers are split substantially equally among all the optical paths within the coupler, so that each optical path exiting the coupler includes light of all the wavelengths initially introduced to the coupler. The wavelength selecting elements disposed on each optical path are situated to direct the light in a manner such that light of only the selected wavelengths interferes constructively at a given exterior coupler port and other wavelengths interfere destructively. Consequently, optical signals composed of N wavelengths may be demultiplexed such that N optical paths carry light having one wavelength.

Abstract: An automated method and apparatus for making optical fiber couplers is disclosed. The apparatus includes various processing stations under the control of a programmable controller. A fiber feeding system receives a set of optical fibers from a reel and guides them to the various processing stations. The fibers are guided into a fiber insertion fixture. The insertion fixture moves the fibers to the aperture of a glass capillary tube. The fibers are then stripped of a portion of their coating. The feeding system feeds the stripped fibers through the insertion fixture and into the glass tube. The fibers are severed and terminated. Subsequently, a burner heats the glass tube, causing it to collapse around the fibers to form a fiber coupler.

Abstract: The end portions of a plurality of optical optical fibers are stripped; the coated portions of the fibers constituting pigtails. The stripped portion of one of the fibers is fused to an uncoated fiber section having a diameter that is larger than that of the stripped fiber end portions. A fiber optic coupler preform is made by surrounding the uncoated fiber section with the stripped portions of the remaining fibers to form a close-packed fiber array. At least a portion of the overlapping region of the uncoated fiber section and the stripped end portions is heated and drawn to induce the coupling of optical signals between the uncoated fiber section and the stripped portions.