Abstract: An optical system includes a delay region having a photonic band structure, a modulated optical signal source, an optical input, and an optical output. The optical input couples modulated input optical signals into a predetermined mode in the delay region such that group velocity of the optical signal is reduced. The optical output includes a wavelength selective element. Input optical signals are coupled into a highly dispersive mode in the delay region in which the group velocity of the optical signal is reduced. The input signal, which has been delayed and dispersed, is recovered at the output of the device using the wavelength selective element.

Abstract: An apparatus for a free space optical communication system includes an element having a front surface and a back surface. A holographic optical element (HOE) is disposed to receive a light signal from the free space optical communication system, and to angularly direct the light signal, having a certain wavelength, towards one of the surfaces of the element to allow the light signal to propagate between the front and back surfaces of the element via total internal reflection. The internally reflected light signal eventually converges and is received at an optical detector circuit. At the same time, light having other wavelengths, including visible background light, passes through the HOE, thereby giving the apparatus an appearance of being transparent and unobtrusive.

Abstract: A tunable chromatic dispersion and dispersion slope compensator that utilizes a Virtually Imaged Phased Array (VIPA), a rotating transmissive diffraction grating, and a mirror with different curvatures for different cross-sections is disclosed. The compensator in accordance with the present invention provides simultaneous tunable compensation of chromatic dispersion and dispersion slope utilizing a single apparatus. The amount of compensation is accomplished by rotating the transmissive diffracting grating and/or translating the mirror. A system which utilizes the compensator is thus cost effective to manufacture.

Abstract: A device and method for compensating for chromatic dispersion in an optical signal. The optical signal is coupled between an optical waveguide of a type having (i) a fundamental-mode waveguide and (ii) a higher-order mode waveguide surrounding the fundamental-mode waveguide, wherein different effective indexes of refraction are associated with the fundamental-mode and higher-order mode waveguides. The device comprises a transmissive, long-period optical grating disposed along a length of the optical waveguide and has a receiving end and a transmitting end. The grating is chirped between the ends along a light conducting axis of the optical waveguide such that different wavelengths of the optical signal are coupled to the fundamental-mode and higher order mode waveguides at different points along the length of the grating so that chromatic dispersion is corrected at the transmitting end.

Abstract: An optical apparatus comprises a phase grating, an input-ring array, an output-ring array and an optical interconnect. The phase grating produces a modulated light beam for each of a plurality of processing elements. The modulated light beams have a plurality of light wavelengths. An input-ring array receives the plurality of data modulated light beams. An output-ring array outputs a light beam to each processing element. An optical interconnect transfers light from the input-ring array to the output ring array and uniquely rotates each wavelength of the transferred light.

Abstract: In one embodiment, the present invention provides a method of transmitting an optical signal. This signal is transmitted through an optical fiber 12 (24) and is amplified by an optical amplifier 14 (22). The signal is then provided to an arrayed waveguide grating 16 (20). The arrayed waveguide grating 16 (20) has a wavelength-dependent optical amplitude response characterized in that the wavelength having the peak optical amplitude is different than the center channel wavelength of the signal. In some instances, this may result in a situation where the total tilt effect for the optical fiber 12 (24), the optical amplifier 14 (22) and the arrayed waveguide grating 16 (20) is less than the total tilt effect for the optical fiber 12 (24), the optical amplifier 14 (22) and an arrayed waveguide grating with a standard wavelength-dependent optical amplitude response where a signal at the center channel wavelength corresponds to the peak optical amplitude of the arrayed waveguide grating.

Abstract: An optical channel dispersion compensating and monitoring apparatus when an optical signal transmits from an optical transmitter to an optical receiver through an optical fiber is disclosed. A WDM optical amplifier comprising the optical channel dispersion compensating and monitoring apparatus, for a long distance is also disclosed. A WDM optical channel dispersion compensating and monitoring apparatus comprises a dispersion compensating unit for compensating the optical signal distorted in the optical fiber at each channel when the optical signal transmits from an optical transmitter to an optical receiver through the optical fiber and an optical channel monitoring unit for converting an optical power as the portion of the compensated optical signal to electric signals and monitoring the converted electric signals.

Abstract: The bidirectional dispersion compensator comprises at least one circulator (Z,Z1,Z2,Z4) and at least one filter-coupler element (F1, etc.). The optical signals (S1,S2) that are emitted in opposite directions are merged and sent to a compensation fiber (LK,LK1, etc.) together, are reflected at the ends of this fiber, and are forwarded in the respective directions of transmission as dispersion-compensated optical signals (SK1 and SK2).

Abstract: The present invention provides methods and optical fibers for periodically pinning an actual (random) accumulated chromatic dispersion of an optical fiber to a predicted accumulated dispersion of the fiber through relatively simple modifications of fiber-optic manufacturing methods or retrofitting of existing fibers. If the pinning occurs with sufficient frequency (at a distance less than or are equal to a correlation scale), pulse degradation resulting from random chromatic dispersion is minimized. Alternatively, pinning may occur quasi-periodically, i.e., the pinning distance is distributed between approximately zero and approximately two to three times the correlation scale.

Abstract: Methods and apparatus for constructing phased array antenna beamforming networks are provided, that allow to scan multiple beams and select appropriate sets of delay lines simultaneously. The beamforming networks disclosed herein generate less losses than conventional ones and in some cases, do not require active switching, making them completely passive. Three main methods are comprised in the invention: (1) laser wavelength hierarchies, (2) arrangements of Wavelengths Division Multiplexing (WDM) components, (3) re-use of laser wavelengths. Multiple laser wavelengths are arranged in groups and subgroups (wavelength hierarchies) in the wavelength domain. By switching between these wavelength groupings, the arrangements of WDM components disclosed herein enable the beamforming network to direct the beam signals to the proper time delay lines, and to differentiate multiple beams.

Abstract: An arrayed waveguide grating optical multiplexer/demultiplexer is provided to suppress a temperature depending characteristic of a center wavelength. The arrayed waveguide grating comprises at least one optical input waveguide, a first slab waveguide, an arrayed waveguide, a second slab waveguide, and a plurality of optical output waveguides. The first slab waveguide is separated on an cross separating plane which is intersected to a path of light passing through the first slab waveguide to constitute separated slab waveguides. A slide moving member is provided which may move at least one of these separated slab waveguides along the cross separating plane, depending upon the temperature. A front surface side of the waveguide forming region and a rear surface side of the substrate are sandwiched by a positional shift suppressing member such as a clip. The possition depressing the waveguide forming region by the clip is escaped from the optical axis of the separated slab waveguides.

Abstract: The present invention is directed to a system and method which utilize an incoherently beam combined (IBC) laser. The IBC laser includes a plurality of emitters with each of the emitters possessing a partially reflective surface on their front facet. The partially reflective surface causes resonant wavelengths to be defined. In certain embodiments, the system and method arrange the external cavity and emitter spacings of the IBC laser such that the center feedback wavelength provided to each emitter is an etalon resonant wavelength. In other embodiments, the range of feedback wavelengths is adapted so that it is greater than the free spectral range (the separation in wavelength space between adjacent etalon resonant wavelengths).

Abstract: An optical signal repeater, in which an output level of each optical signal of WDM optical signals does not change even when the number of wavelengths of inputted WDM optical signals changes, amplifies WDM optical signals transmitted from an optical transmitter via an optical fiber transmission line. A pumping light source outputs pumping light used for amplifying the WDM optical signal. A multiplexer transmits the pumping light to an amplifier, and a splits the amplified WDM optical signals into two parts. A wavelength selection type reflector reflects only an optical signal having a specified wavelength in one part of the amplified WDM optical signals. An automatic output level controller controls the pumping light output from the pumping light source so that the power level becomes a designated level. A reflected optical signal transmitter transmits the optical signal having the specified wavelength reflected to the automatic output level controller.

Abstract: The present invention relates to a method for synthesizing supergratings using Fourier analysis. The method divides the synthesis process into two stages: synthesis of an “analog” grating profile, followed by a quantization step. The method provides a generalized procedure for analog synthesis by drawing on the Fourier approximation and on finite-impulse-response (FIR) filter design theory, while it interprets the simple threshold quantization as a “zeroth order” Delta-Sigma Modulator, which it improves.

Abstract: The frequency-selective optical multiplexer comprises, an LC polarization controller, a spectral demux/mux and input/output optics including two ports, a first optical path spatially separated from a second optical path and polarization-dispersive optics. The polarization dispersive optics are disposed between the ports and the optical paths; generate from an optical signal a pair of polarization components, composed of a first polarization component and a second polarization component having orthogonal polarizations; and output the first and second polarization components via the first and second optical paths, respectively. The first and second polarization components have first and second polarizations when the optical signal is received at one port, and have the second and the first polarizations, respectively, when the optical signal is received at the other port.

Abstract: An optical multiplexer and demultiplexer for dense wavelength division multiplexed (“DWDM”) fiber optic communication systems is disclosed. As a multiplexer, the device functions to spatially combine the optical signals from several laser sources (each of which is a different wavelength) and launch the spatially combined laser beams into a single optical fiber. As a demultiplexer, the device functions to spatially separate the different wavelengths of a wavelength division multiplexed optical link and launch each of the different wavelengths into a different optical fiber. In either embodiment, the device includes both bulk optic and integrated optic components. The spatial separation or spatial combination of laser beams of different wavelength is achieved with the use of bulk diffraction gratings.

Abstract: An optical wavelength division multiplexing transmission network system having a star-topology network is disclosed, which comprises an arrayed-waveguide grating type multiplexing/demultiplexing circuit having N input ports and N output ports, and N transmitting/receiving apparatuses, each apparatus including a transmitter, receiver, demultiplexer, multiplexer, and N 2-input and 2-output optical path switching elements corresponding to N wavelengths, so as to cope with a damage to a transmitting or receiving portion corresponding to a specific wavelength. Each switching element is independently switched between first and second connective conditions.

Abstract: The device, which has a modular structure, makes use of Bragg gratings for selecting, from a wavelength division multiplexed stream, a carrier to be inserted or extracted, and optical circulators for receiving the stream, for extracting and inserting the carriers and for sending the multiplexed stream to the output after the extraction and insertion of the carriers. The grating and the receiving-extracting circulator are located in a structural module which is replicated for all the channels to be extracted and inserted.

Abstract: A wavelength division multiplexing ring network is constructed using a simple architecture and a fewer number of hardwares between the nodes compared with the conventional ring network. Each node is structured so that any number of multiple waves can be processed, and a fault in the network or within a node is resolved by providing a path-based protection so that switching can be performed without disrupting other nodes or even within one node.

Abstract: An optical delay unit comprises a periodic wavelength demultiplexer having M (M is a natural number) input ports including a signal input port, M output ports including a signal output port, and periodic input/output characteristics for wavelengths between the M input ports and the M output ports, and (M−1) optical paths to connect each of the (M−1) output ports in which the signal output port is excluded from the M output ports of the periodic wavelength demultiplexer with any of the (M−1) input ports in which the signal input port is excluded from the M input ports of the periodic wavelength demultiplexer.

Abstract: An optical packet header identifier having a simplified configuration and being superior in reliability, stability, and economical efficiency, an optical router incorporating the identifier therein, and a routing method using the optical router are provided.

Abstract: In a device for regenerating a wavelength-division multiplex optical signal, the optical signal to be regenerated comes from an optical fiber and is injected back into the same optical fiber or into another fiber. The device comprises at least one dispersive medium for receiving the wavelength-division multiplex signal and emitting a corresponding dispersed wave into a free space and a saturable absorber which receives the dispersed wave and transmits a corresponding regenerated wave.

Abstract: The optical device is located at a node connected of an optical network. The optical device receives optical signals, each received signal having a different wavelength. The optical device comprises a wavelength-selective optical tap that selectively drops a first portion of the optical power of a received optical signal having a specific wavelength. The optical device also optically conveys the optical signal having the specific wavelength to a next node, the conveyed optical signal having a second portion of the optical power of the received optical signal having the specific wavelength.

Abstract: A high-capacity optical transmission arrangement utilizing a plurality of laser sources and a plurality of wide-band optical amplifiers permit the reliable transmission of 1 Tb/sec rates over significant distances of optical fiber.

Abstract: An optical apparatus comprises a phase grating, an input-ring array, an output-ring array and an optical interconnect. The phase grating produces a modulated light beam for each of a plurality of processing elements. The modulated light beams have a plurality of light wavelengths. An input-ring array receives the plurality of data modulated light beams. An output-ring array outputs a light beam to each processing element. An optical interconnect transfers light from the input-ring array to the output ring array and uniquely rotates each wavelength of the transferred light.

Abstract: At one side of a substrate, a vertical diffraction grating is formed integrated with the substrate, at the other side of the substrate, one pair or more of fibers are disposed through which either light goes from the vertical diffraction grating or light comes into the vertical diffraction grating, and a lens member is disposed between the fibers and the vertical diffraction grating. At the other side of the substrate, positioning means which positions a plurality of fibers is formed integrated with the substrate, and a space between the vertical diffraction grating and the fibers constitutes a waveguide.