Abstract: The dynamic gain equalizer for flattening a gain profile of an optical amplifier includes: an optical waveguide circuit having multistage optical couplers, demultiplexing and multiplexing, each formed by connecting optical couplers arranged at a plurality of stages; and optical connecting circuits including optical phase shifters each capable of changing a phase of propagating light and optical delay lines each for adding a predetermined delay time to the propagating light, said dynamic gain equalizer in which at least one of the optical couplers in the two multistage optical couplers are provided with variable optical amplitude means, respectively, and each of the multistage optical couplers are formed asymmetrically with respect to an extension of a line which connects a center arranged position of optical outputting ends of the demultiplexing multistage optical coupler with a center arranged position of optical inputting ends of the multiplexing multistage optical coupler.

Abstract: In an optical fiber system for delivering laser, a laser beam is focused onto an optical fiber at an injection port of the system. The end portions of the fiber have cladding treatments to attenuate stray light and cladding mode light, so as to enhance the protection of the outer layer joint points. Photodetector sensors monitor scattered stray light, cladding mode light, and/or transmitted cladding mode light. Sensor signals are provided to a control unit for analyzing the fiber coupling performance. If need be, the control unit can control a laser shutter or the like to minimize or prevent damage. In materials processing applications, the photodetector signals can be analyzed to determine the processing status of a work piece.

Abstract: A method of simultaneously specifying the wavelength dispersion and nonlinear coefficient of an optical fiber. Pulsed probe light and pulsed pump light are first caused to enter an optical fiber to be measured. Then, the power oscillation of the back-scattered light of the probe light or idler light generated within the optical fiber is measured. Next, the instantaneous frequency of the measured power oscillation is obtained, and the dependency of the instantaneous frequency relative to the power oscillation of the pump light in a longitudinal direction of the optical fiber is obtained. Thereafter, a rate of change in the longitudinal direction between phase-mismatching conditions and nonlinear coefficient of the optical fiber is obtained from the dependency of the instantaneous frequency. And based on the rate of change, the longitudinal wavelength-dispersion distribution and longitudinal nonlinear-coefficient distribution of the optical fiber are simultaneously specified.

Abstract: A method for adaptively fabricating a waveguide comprises: measuring misplacement of a photonic device relative to a substrate; generating computer readable instructions for using a plurality of graphics primitives to form the waveguide; and photocomposing the waveguide on the substrate in accordance with the computer readable instructions. A reticle comprises a plurality of graphics primitives with at least one of the plurality of graphics primitives comprising a tapered end. A waveguide comprises a plurality of waveguide segments with each of the plurality of waveguide segments comprising a tapered end and being adjacent to at least one other of the plurality of waveguide segments.

Abstract: The manufacture of optical devices by reversing domains in specific patterns in ferroelectric crystal material is practiced using a segmented electrode rather than a continuous electrode on at least one of the surfaces of the ferroelectric crystal material. Independent poling voltages are selectively applied to the segments to create various electric fields inside the ferroelectric crystal material. In this manner, portions of the desired domain-reversed pattern are individually established in the ferroelectric crystal material in high fidelity with their respective electrode segments so that upon completion of poling, the entire domain-reversed structure is established in the ferroelectric crystal material in high fidelity relative to the entire electrode. Parameters of the electrode segment that may be varied singly or in combination to achieve a desired degree of fidelity include the overall size of the electrode segment, as well as the shape and size of the features included in the electrode segment.

Abstract: A system and method for wavelength division multiplexing and demultiplexing with broadened and flattened passband profiles are disclosed. A spectral modifying element may be used to broaden and flatten the passband profile of associated multiple wavelength optical signals and spectral components. The system preferably includes a light focusing device and a diffraction grating having a direction of dispersion. The spectral modify element primarily transforms or broadens and flattens optical signals in only the direction of dispersion of the associated diffraction grating.

Abstract: A telecommunications optical fiber is secured against intrusion by detecting manipulation of the optical fiber prior to an intrusion event. This can be used in a non-locating system where the detection end is opposite the transmit end or in a locating system which uses Fresnel reflections and Rayleigh backscattering to the transmit end to detect and then locate the motion. The Rayleigh backscattering time sliced data can be stored in a register until an intrusion event is detected. The detection is carried out by a polarization detection system which includes an optical splitter which is manufactured in simplified form for economic construction. This uses a non-calibrated splitter and less than all four of the Stokes parameters. It can use a polarimeter type function limited to linear and circular polarization or two linear polarizers at 90 degrees.

Abstract: In a wavelength converting method, an ambient that is in contact with a surface of a non-linear optical crystal from which wavelength-converted light is outputted is a gas that is lower in content of nitrogen than air. A wavelength converting device includes a device for controlling the ambient in contact with a surface of the non-linear optical crystal from which the wavelength-converted light is outputted so the ambient is lower in nitrogen than air. A laser machining device includes the wavelength converting device.

Abstract: An optical fiber comprising: (i) a silica based, rare earth doped core having a first index of refraction n1; (ii) a silica based inner cladding surrounding the core having a second index of refraction n2, such that n1>n2; (iii) a silica based outer cladding surrounding the inner cladding having a third index of refraction n3 such that n2>n3, wherein inner cladding diameter is at least 125 ?m.

Abstract: A method for thermally stabilizing an optical parametric oscillator (OPO) 10 to maintain constant optical path length for stable high power output places a beam dump 32 outside an OPO cavity 18. The OPO 10 has a nonlinear crystal 22 within cavity 18 for splitting a single input pump beam 14 into lower energy signal and idler beams 16, 18. The method includes providing a cavity exit port for unconverted pump and generated idler beams, and absorbing unconverted beams in beam dump 32. The method includes athermalization by actively cooling surfaces used as an optics mounting base, and athermalization by constraining the size of cavity 18 by using thermally stiff members, guiding pins or rails, or by using bimetallic materials with different expansion.

Abstract: A device which in an optical interface adapts XFP to a 300 pin MSA transponder socket, permitting replacement of 300 pin MSA transponders with an XFP module on an existing host circuit pack. The device performs dispersion compensation in a removable module, addressing issues of jitter, path length equalization, cross talk and electromagnetic compatibility. As deployed, the device presents at the optical interface the attributes of XFP, hence connected optical devices are “fooled” into reading a connection to XFP instead of the 300 pin MSA.

Abstract: A tetragonal lattice is formed by first cylindrical structural members, and a photonic crystal has a periodical structure formed by a periodical arrangement of such tetragonal lattice. A distance between center points of the first cylindrical structural members is taken as a unit length a, which constitutes a lattice constant of the tetragonal lattice. At an approximate center of the tetragonal lattice, a cylindrical structural member is provided, and a dielectric area is provided around the first cylindrical structural members and the second cylindrical structural member. This structure allows the formation of a photonic band gap for a TE wave and a photonic band gap for a TM wave in a certain common frequency region, thereby forming a complete band gap.

Abstract: An optical frequency converter that can use a low-amplitude, high-frequency signal for converting a wide range of optical frequencies. The optical frequency converter includes a device for modulating a lightwave of a preset frequency with a modulation signal to generate a group of sidebands thereof, a device for selecting sidebands from among the group of sidebands, and a device for changing modulation signal frequencies and selecting specific sidebands.

Abstract: A technique is provided for automatic optimization of a splice loss estimator of a fiber splicer (1), where the splice loss estimator is adapted, in a splice loss estimation procedure, to estimate the splice losses (Lti) of splices (i) of optical fibers as produced by the fiber splicer from images taken of the optical fibers at the splicing thereof, and the splice loss estimation procedure includes the use of splice loss estimation parameters (Pj). The estimator estimates splice losses based on information (Cij) obtained from the images and the estimation parameters. Further, the splice losses are measured by means of a measurement instrument (3). The estimated (Lti) and measured (LMi) splice losses, and the information obtained from the images are uploaded (71) into an off-line computer (5) and the key estimation parameters are automatically optimized by the selection of any solution within the Bellcore accuracy criteria (75), whereafter the optimized estimation parameters are downloaded (81) to the splicer.

Abstract: This invention pertains to a device for broadening optical wavelength in the 2–14 ?m region comprising a light source and a highly nonlinear chalcogenide fiber associated therewith whereby a light signal is passed from the light source into the fiber wherein and through interactions between the light signal and the material, bandwidth of the light signal is broadened in the 2–14 ?m region.

Abstract: A device and method for processing a signal e.g. equalizing a signal, is disclosed. Such processing involves dividing a signal into two portions that each traverses a wavepath and then are combined. The respective wavepaths impose a non-linear frequency-versus-phase dependency on a signal portion. The frequency-versus-phase dependencies that characterize the respective wavepaths are similar in shape but inverted from each other. A processed signal has significantly improved signal-to-noise ratio.

Abstract: The present invention provides an optical switch whose operational characteristics do not change, and which is not affected by polarization cross talk, even when the wavelength of a signal light or the ambient temperature of the optical switch varies. The optical switch comprises first and second polarization splitting/combining modules, (10,18), first and second polarization-maintaining single-mode fibers (12, 16), a first polarization plane conversion portion (14), third and fourth polarization-maintaining single-mode fibers (22, 26), and a second polarization plane conversion portion (24).

Abstract: A device for varying the direction of an optical beam. A first waveguide is directed along a first direction, a second waveguide is directed along a second direction different from the first direction, and a bending region is interposed between the first and the second waveguide. The bending region has a photonic crystal having a regular periodicity and at least a first and a second crystal axes substantially aligned with the first and second directions, and a reflecting surface delimiting the photonic crystal and so positioned and oriented as to reflect an optical beam coming from the first waveguide toward the second waveguide.

Abstract: A multi-layer laterally-confined dispersion-engineered optical waveguide may include one multi-layer reflector stack for guiding an optical mode along a surface thereof, or may include two multi-layer reflector stacks with a core therebetween for guiding an optical mode along the core. Dispersive properties of such multi-layer waveguides enable modal-index-matching between low-index optical fibers and/or waveguides and high-index integrated optical components and efficient transfer of optical signal power therebetween. Integrated optical devices incorporating such multi-layer waveguides may therefore exhibit low (<3 dB) insertion losses. Incorporation of an active layer (electro-optic, electro-absorptive, non-linear-optical) into such waveguides enables active control of optical loss and/or modal index with relatively low-voltage/low-intensity control signals. Integrated optical devices incorporating such waveguides may therefore exhibit relatively low drive signal requirements.

Abstract: An optical transmitter and receiver module which can enhance a coupling comprises a light source emitting the first light, a light-receiving section receiving the second light, a diffraction device changing the direction of travel of at least one of the first light and the second light, a first lens which condenses the first light, outgoing from the light source and entering through the medium of the diffraction device, onto a light input/output face of the optical fiber and condenses the second light outgoing from the optical fiber onto the light-receiving section through the medium of the diffraction device, and a second lens which inhibits a beam of the first light outgoing from the light source from diverging and allows it to enter the first lens through the medium of the diffraction device.