Abstract: A method and apparatus is described for controlling the attenuation of multiple wavelengths signals propagating in an optical fiber, that may have a time-dependent power in each signal, to provide an output signal having a desired attenuated power in each of the multiple signals. An equalizer may be used that has various optical elements to focus and disperse light, such as a concave diffraction grating and a modulator array having modulators disposed on a concave surface. The equalizer may also be coupled to various components such as a circulator or thermally expanded core fibers.

Abstract: We present a method and apparatus for local and superficial measurement of the optical properties of turbid media. The depth probed is on the order of 1 transport mean free path of the photon. The absorption coefficient, reduced scattering coefficient and the phase function parameter ?=(1?g2)/(1?g1) are optical parameters computed from a single measurement of the spatially resolved reflectance close to the source. Images of superficial structures of the medium can be obtained by performing multi-site measurements. An important application of this technique is the characterization of biological tissues, for example for medical diagnostic purposes. Measurements on biological tissues can be achieved using a probe of diameter less than 2 mm, and the average volume probed is on the order of 1 mm3. Separate images of absorption and tissue structure can be achieved with a resolution of approximately one transport mean free path of the considered tissue.

Abstract: The index of refraction of waveguide structures can be varied by altering carrier concentration. The waveguides preferably comprise semiconductors like silicon that are substantially optically transmissive at certain wavelengths. Variation of the carrier density in these semiconductors may be effectuated by inducing an electric field within the semiconductor for example by apply a voltage to electrodes associated with the semiconductor. Variable control of the index of refraction may be used to implement a variety of functionalities including, but not limited to, tunable waveguide gratings and resonant cavities, switchable couplers, modulators, and optical switches.

Abstract: The invention relates to an optical device which carries multiple optical signals where the optical device has a plurality of distal waveguides some of which may be configured to control insertion loss among the multiple optical signals.

Abstract: The present invention seeks to provide a GFF with a technique amenable to manufacturing in large volume and having a filter with a more precise control of the spectral response.

Abstract: The present invention relates to an optical communication system having a flat gain spectrum and an excellent pumping efficiency in a signal wavelength band, and comprising a structure which is realizable/operable at a low cost. This optical communication system comprises an optical transmission line including a plurality of Raman amplification optical fibers, and pumping light suppliers for supplying pumping light to the Raman amplification optical fibers. In particular, two Raman amplification optical fibers selected from the plurality of Raman amplification optical fibers included in the optical transmission line differ from each other in at least one of the wavelength at which the gain of Raman amplification becomes the highest, and the number of channels at which the gain of Raman amplification is maximum.

Abstract: A method for operating a planar lightwave circuit at a constant power consumption, comprises providing a matrix of integrated active elements, heating independently each active element with a separate heating power, and cooperatively operating the heating powers of the active elements to keep a sum of the operating heating powers constant in time independently on the dynamic operation of the element. The active element has two connecting configurations and is operative to have a phase change in a light beam passing through each of the connecting configurations, both connecting configurations being constantly heated. The active element is operable in both analog and digital modes with a constant power consumption.

Abstract: An optical attenuator has a planar MEMS substrate supporting two optical fibers; an actuator; and a silicon vane actuatable by said actuator for a movement into and out of the optical beam passed between the fibers. The vane is configured to divert at least a portion of the optical beam off the optical axis when the element is moved into the optical beam. The vane has at least one surface disposed non-perpendicularly relative to the optical axis of the beam. The vane may be of a wedged shape.

Abstract: The incident angle of the beam with regard to an etalon is arranged finely tunable by either rotating the etalon provided with a plane of incidence inclined with regard to the rotational axis thereof in the vicinity of the optical axis or rotating a lens whose edge surface is obliquely ground around the optical axis, which allows the incident angle of the laser beam with regard to the etalon to be adjusted and fixed with high precision.

Abstract: A multi-wavelength cascaded Raman resonator (“MWCRR”). The MWCRR has an optical source for pumping optical radiation centered around an input wavelength. The MWCRR further includes a Raman fiber having at least a first set of optical gratings for converting the pumped optical radiation to wavelengths other than the input wavelength. The Raman fiber also has at least one adjustable output coupler having a variable reflectivity for controlling the power of the optical radiation propagating from the at least one set of optical gratings at the wavelengths other than the input wavelength.

Abstract: An interconnect element incorporates a plurality of smaller, substantially identical, interconnect modules. Multiple identical elements can in turn be combined to form larger interconnect networks. Signal paths in the elements can be implemented with optical fibers or electrical conductors.

Abstract: A method for producing a ferrule having a plurality of fiber holes for insertion of optical fibers formed between two pin holes for insertion of guide pins, and a ferrule produced by the method. The method comprises a step of injecting a synthetic resin in a mold for forming the ferrule while holding a plurality of pins with a Young's modulus of(22 to 59)×1010N/m2 for forming the fiber holes at two points separated by a distance of 1.5 to 4 mm in a lengthwise direction of the pins.

Abstract: The Multimode Interference coupler according to the invention has smoothly continuous inwardly tapered sidewalls (301) which define the width of the multimode region (W1) along the propagation axis of the device. The inward taper causes the average width of the device to be reduced in comparison to known couplers having straight sidewalls (202). Further, invention allows the access waveguides (303, 309) to remain sufficiently spaced, while reducing the overall length of the device, to avoid lithographic gap fill-in and unwanted optical coupling between the waveguides.

Abstract: An improvement to video projectors having a reflector/lamp for compressing light to a focal point at a predetermined f/#, an integrating rod positioned at the focal point to collect and integrate the light, and a detector for sensing light output from the integrating rod, the improvement comprising a converging lens positioned between the reflector/lamp and the integrating rod for compressing the focal point so as to increase the amount of light entering the integrating rod while consequentially decreasing said f/#, and a diverging lens for increasing the focal point within the integrating rod so as to restore said predetermined f/#. Preferably, the diverging lens is fabricated from gradient index glass.

Abstract: A dispersion compensating fiber 1 is placed in the form of a coil or bundle within a housing 2, and a filling material 3 having a viscosity of 0.01 Pa·s to 0.6 Pa·s at normal temperature before curing is filled in a space around the dispersion compensating fiber 1 within the housing 2 and then the filling material is cured. As a result, a change of transmission loss caused by a temperature variation due to heat cycles of the dispersion compensator can be reduced. A difference in transmission loss can be further reduced by employing a method of placing the dispersion compensating fiber in the housing in the form of a loosely wound bundle and then pouring the filling material, or a method of applying vibration to the housing, in which the dispersion compensating fiber is placed, when pouring the filling material.

Abstract: An optical filter comprising a first CBG including a first end and a second end, a second CBG of the same structure as the first CBG, including a third end of the same structure as the first end and a fourth end of the same structure as the second end, and a circuit including an input port and an output port. The circuit receives a first optical signal via the input port and brings it to the first end of the first CBG, the circuit receives a second optical signal produced by reflecting the first optical signal from the first CBG and brings the second optical signal to the fourth end of the second CBG, and the circuit receives a third optical signal produced by reflecting the second optical signal from the second CBG and outputs the third optical signal via the output port.

Abstract: An optical attenuator includes a holding sleeve, a pair of ferrules inserted into and fixed to the holding sleeve such that the ferrules oppose each other at base ends thereof at a predetermined distance between each base end, and an attenuating fiber inserted into and fixed to the pair of ferrules such that ends of the attenuating fiber are exposed. The optical attenuator is also provided with an opening in the holding sleeve so as to communicate with the outside. A filler is supplied into the sleeve through the opening.

Abstract: A connector assembly for connecting and aligning an active optical component with an optical waveguide is provided. The assembly comprises: (i) a waveguide chip having an optical waveguide embedded beneath a cladding layer and a cavity for accommodating the active optical component comprising at least one wall extending from the surface of the cladding layer through the waveguide; and (ii) a second chip for carrying the active optical component. The waveguide chip comprises a locating stop and the second chip has first and second reference regions formed thereon, the first reference region being adapted to locate the active optical component, and the second reference region being adapted to engage the surface of the cladding layer and the locating stop of the waveguide chip when the waveguide chip and second chip are connected together with the active optical component located within the cavity in order to provide alignment of the waveguide with the active optical component.

Abstract: A phosphor coated waveguide for efficient collection and detection of back-scattered electrons in an electron beam apparatus such as a scanning electron microscope is disclosed. The waveguide for directing photons to an optical detector generally comprises a first waveguide portion having opposing first and second faces defining a beveled hole therebetween to allow an electron beam to pass therethrough, the beveled hole decreasing in cross-sectional size from the first to the second face. A phosphor coating on the second face around the beveled hole converts the back-scattered electrons to photons. The first waveguide portion may include angled faces at an end further from the optical detector. A surface defined by the beveled hole and/or the angled faces may have a reflective coating. The waveguide may also include a second waveguide portion that adjoins and flares out relative to the first waveguide portion to further increase waveguide efficiency.

Abstract: This invention discloses an optical interleaver that includes a first collimating lens for collimating an input optical signal into collimated beams and a second collimating lens for focusing the collimated parallel beams into an output optical fiber. The interleaver further includes a phase delay difference generating means for generating a phase-delay difference between portions of the collimated parallel beams for generating an interference in the second collimating lens for selectively enhance signal transmission of certain wavelengths. In a preferred embodiment, the phase delay difference generating means comprising a glass plate blocking a portion of the collimated parallel beams for generating a phase delay for a portion of the collimated parallel beams passing therethrough. In another preferred embodiment, the phase delay difference generating means comprising a glass plate having an upper portion covering an upper portion of the collimated parallel beams.