Abstract: An optical conversion device for a shared FTTH distribution network including first and second optical fibers and an optical processing circuit. The optical processing circuit has an input for receiving a first optical analog signal carried by the first optical fiber and an output for providing a first optical digital signal for transmission via the second optical fiber. The optical processing circuit is configured to digitize the first optical analog signal and incorporate into the first optical digital signal. The optical analog signal may be an optical signal which is modulated by an RF signal, which is the same or similar to that of existing HFC networks. High loss electrical signals are converted to low-loss optical signals propagated within the optical plant. The combined optical analog and digital protocol supports analogous communications of existing HFC networks and the optical plant minimizes cost of fiber optic upgrade.

Abstract: In a multi-wavelength spectroscopic apparatus using diffraction gratings, a first diffraction grating is a diffraction grating with diffraction efficiencies of p-polarized light and s-polarized light being equal on a short wavelength side of an operating wavelength range, and a second diffraction grating is a diffraction grating with diffraction efficiencies of p-polarized light and s-polarized light being equal on a long wavelength side of an operating wavelength range. By performing dispersion with two such diffraction gratings, it is possible to enlarge the amount of angular dispersion, and to produce a spectroscopic apparatus, which cancels wavelength dependencies of the diffraction efficiencies and has a small wavelength dependency of the diffraction efficiency.

Abstract: An integrated DWDM transmitter apparatus includes a support component and a silica-on-silicon substrate overlying the support component. The support component includes a temperature adjustment component. The silica-on-silicon substrate overlies the support component and includes a silica layer and a silicon layer. The silica-on-silicon substrate includes a corresponding a substrate surface which includes a first surface region and a second surface region. In an embodiment, the two surface regions are not coplanar. The transmitter apparatus includes an optical multiplexer within the silica layer, the optical multiplexer including a plurality of input waveguides and at least an output waveguide. The transmitter apparatus also includes one or more semiconductor laser array chips overlying the first surface region of the silica-on-silicon substrate. Each of the laser array chips including two or more lasers, which are optically coupled to corresponding ones of the plurality of input waveguides.

Abstract: There is provided a fiber optic system comprising: a multi-wavelength source adapted to generate frequency modulated signals having different wavelengths, ?1, ?2, . . . , ?n; and an arrayed waveguide grating adapted to convert the multiplicity of frequency modulated signals into a multiplicity of substantially amplitude modulated signals, and spatially combine the different wavelengths ?1, ?2, . . . , ?n. And there is provided a method for transmitting an optical signal through a fiber comprising: operating a multi-wavelength source so as to generate frequency modulated signals having different wavelengths, ?1, ?2, . . . , ?n; passing the frequency modulated signals through an arrayed waveguide grating so as to convert the frequency modulated signals into substantially amplitude modulated signals, and spatially combine the different wavelengths ?1, ?2, . . . , ?n; and passing the substantially amplitude modulated signals into the fiber.

Abstract: Hierarchical hybrid optical networking is based on balancing cost and performance of optical networks by providing transparent (optical) switching of subsets of wavelengths in addition to opaque (electrical) switching of individual light paths. Effective use of wavelength-subset switching requires aggregating and deaggregating wavelength subsets in a simple, cost-effective manner. Non-uniform wavebands are introduced and analyzed their performance advantage as compared with uniform wavebands. Also proposed are several architectural options for a hierarchical hybrid optical cross-connect system that combines non-uniform wavebands and improved utilization of OEO ports.

Abstract: To resolve problems, with the invention, an optical transmitter comprises an encoder for generating an optical signal obtained by encoding multi-wavelength pulses corresponding to sending data by use of a method of time spread/wavelength hopping in accordance with an encoding pattern of the encoder itself. The encoder concurrently executes time delay for every wavelength component at encoding, and time delay due to pre-compensation processing to pre-compensate for difference in propagation time for every wavelength component, occurring due to chromatic dispersion characteristics of a transmission line by ?%. An optical receiver comprises a decoder for decoding the optical signal transmitted by the optical transmitter in accordance with a decoding pattern of the decoder itself.

Abstract: A wavelength filter, for filtering a WDM signal, comprises a demultiplexer, a multiplexer, and a control array connecting the demultiplexer and the multiplexer, where the demultiplexer and the multiplexer have a free spectral range (FSR) smaller than their wavelength channel span.

Abstract: An optical SSB-SC modulation section 13 subjects an optical signal fa outputted from an optical source 11 to an optical SSB-SC modulation based on the amplitude of an external electric signal fc to thereby output an optical intensity-modulated signal. An optical phase modulation section 14 subjects the optical signal fa to an optical phase modulation based on the amplitude levels of the first to nth external electric signals having frequencies f1 to fn to thereby output the resultant signal as an optical phase-modulated signal. An optical combining section 15 combines together the optical intensity-modulated signal and the optical phase-modulated signal. An optical detecting section 16 performs an optical homodyne detection through a squared detection of the optical intensity-modulated signal and the optical phase-modulated signal combined together to thereby produce a wideband modulated signal, being the difference beat signal between the two optical signals.

Abstract: An optical communication network system and a wavelength-routing device and a communication node therefor are provided which can easily increase the optical paths between communication nodes, which are capable of expanding transmission capacity, and which excel in flexibility and expandability. An optical signal within a wavelength band (?Bm±??m) which has been transmitted from a predetermined communication node (200-1 through 200-4) is subjected to wavelength-band demultiplexing of the wavelength bands by wavelength-band demultiplexers (220-1 through 220-4) of a wavelength-routing device (210), and is then subjected to wavelength-routing by arrayed-waveguide gratings (241 through 244) according to the wavelength bands, and furthermore is multiplexed with optical signals of other wavelength bands by wavelength-band multiplexers (230-1 through 230-4), and after having been outputted, is transmitted to a communication node.

Abstract: A multiple wavelength light source generates an output signal having a comb of accurately spaced apart frequencies with variable free spectral range in the C-band of optical fiber communication. The light source employs an electro-optical modulator (EOM) driven by a signal generator which modulates with EOM with multiple modulation frequencies to widen the output spectrum of signal. The EOM has a crystal provided with a waveguide. The waveguide may be doped with a rare-earth metal to impart gain properties to equalize the intensities of the comb. In one preferred embodiment, Er, Yt or other doping elements provide the gain property to waveguides. The crystal is also provided with periodically poled structure, and this may be engineered so as to form domains of unequal widths to improve the efficiency of modulation. The output signal from the light source may be split and presented to a bank of filters to create a multiple signals, each signal having one of the spaced apart frequencies.

Abstract: A single pulse laser beam of linear polarization is irradiated to a glass region such that the condensing point is located inside of the glass region, thereby to form, at the condensing point, a periodic structure region in which high refractive-index zones and low refractive-index zones are repeatedly being generated at pitches of 1 ?m or less. Planes in which the high refractive-index zones or the low refractive-index zones are being joined to one another, are formed in parallel to the polarized magnetic field direction of the pulse laser. It is therefore possible to prepare an optical structural body having a submicron-order fine periodic structure which can readily be produced.

Abstract: The present invention comprises an arrayed waveguide grating member, a taper multimode interference coupler and a taper optical attenuator to uniform and flatten a passband in an optical device.

Abstract: The present invention provides methods and devices for optical performance monitoring using co-located switchable fiber Bragg gratings (FBGs) in conjunction with a few detectors. This arrangement combines the merit of both tunable FBG filters and discrete detectors to achieve high spectral resolution, fast detection process and great dynamic range. By using parallel co-located FBGs in conjunction with a banded architecture, the tuning range of each FBG becomes much smaller (equivalent of ˜0.08% strain). As a result, not only does the update speed of the spectral characteristics for each channel become much faster, but it effectively eliminates the concern of FBG long-term reliability as well.

Abstract: A dynamic equalizing optical channel router includes an input port for receiving a wavelength division multiplexed composite optical signal comprising a plurality of channels; at least one output port; a diffraction grating optically coupled to the input and output ports; a lens optically coupled to the diffraction grating at a side opposite to the input and output ports; an array of steering devices optically coupled to the lens at a side opposite to the diffraction grating, wherein each channel is reflected by a different steering device of the array; and a plurality of attenuators, wherein each channel reflected by the array traverses one of the attenuators and the diffraction grating to the at least one output port. The router is able to dynamically adjust optical intensity of each wavelength channel by a different amount while also performing the function of wavelength routing.

Abstract: An exemplary embodiment of the present invention includes an optical circulator. The circulator may have, for example, a first port, a second port, and a third port. The first port may be configured to introduce light into the optical circulator. The system may also include a tunable fiber filter Bragg grating connected to the second port of the circulator and a tunable dispersion-compensating fiber Bragg grating connected to the third port of the optical circulator. The tunable dispersion compensating fiber Bragg grating and the tunable fiber filter Bragg grating may be configured to be tuned by a single actuator. This tuning may be either compression or strain tuning.

Abstract: A digital optical network (DON) is a new approach to low-cost, more compact optical transmitter modules and optical receiver modules for deployment in optical transport networks (OTNs). One important aspect of a digital optical network is the incorporation in these modules of transmitter photonic integrated circuit (TxPIC) chips and receiver photonic integrated circuit (RxPIC) chips in lieu of discrete modulated sources and detector sources with discrete multiplexers or demultiplexers.

Abstract: An optical apparatus comprises a planar optical waveguide having at least two reflectors. The planar optical waveguide substantially confines in at least one transverse spatial dimension optical signals propagating therein, and the reflectors define an optical resonator that supports at least one resonant optical cavity mode. At least one of the reflectors comprises a set of diffractive elements arranged: so that an optical signal in one of the resonant optical cavity modes is successively incident on the diffractive elements; so as to exhibit a positional variation in amplitude, optical separation, or spatial phase; and so as to apply a transfer function to the optical signal successively incident on the diffractive elements. The transfer function is determined at least in part by said positional variation in amplitude, optical separation, or spatial phase exhibited by the diffractive elements.

Abstract: A system for a re-configurable optical de-multiplexer, multiplexer or add/drop multiplexer is provided. A re-configurable de-multiplexer system comprises a wavelength selective switch having an input port, an output port and an internal port; a wavelength division de-multiplexer (WDM) optically coupled to the internal port and a plurality of dropped-channel ports optically coupled to the WDM. The wavelength selective switch receives a plurality of input wavelength-division multiplexed channels from the input port and routes a first subset of the channels to the output port and a second subset of channels to the internal port and then to the WDM. The WDM separates each of the dropped channels to a different respective one of the channel ports.

Abstract: An optical apparatus comprises a planar optical waveguide and at least one set of diffractive elements formed in or on the waveguide. The waveguide is arranged to confine propagating optical signals in at least one transverse dimension. The diffractive element set collectively exhibits a positional variation in diffractive amplitude, optical separation, or spatial phase over some portion of the set. The diffractive element set is collectively arranged to route, as an output optical signal, between corresponding input and output optical ports, a corresponding diffracted portion of an input optical signal. The diffractive element set is collectively arranged so that the input optical signal or the output optical signal is successively incident on the diffractive elements.

Abstract: An optical add and drop multiplexer system comprising a first module for providing a first signal; a second module for providing a second signal; and a modulator for receiving a channel of the first signal at a first location, the first location configured to actuate between a first configuration and a second configuration, wherein the modulator directs the channel of the first signal as an output signal when the first location is in the first configuration. The modulator may direct the channel of the first signal as a dropped signal when the first location is in the second configuration. The modulator may also receive a channel of the second signal from the second module at a second location configured to independently actuate between the first configuration and the second configuration.

Abstract: The present invention overcomes problems associated with switch isolation, noise and crosstalk suppression, insertion loss, spurious reflections, wavelength tolerance, and compactness that are present in varying degrees in other add/drop systems. The present invention includes devices or components that include, but are not limited to high efficiency switchable gratings.

Abstract: The invention includes an apparatus for modulating an optical signal. The apparatus includes a modulating mechanism comprising a plurality of modulating component arrays, each modulating component array comprising a plurality of modulating components, wherein adjacent ones of the plurality of modulating components in each modulating component array are separated by gaps, and wherein adjacent ones of the plurality of modulating component arrays are offset along a dispersion direction of an incident optical signal such that the gaps associated with the adjacent ones of the plurality of modulating component arrays are offset. In one embodiment, rows of the modulating components in the modulating component arrays are offset along the dispersion direction of the incident optical signal by a fraction of the modulating component pitch.

Abstract: This invention provides a system that combines a wavelength multiplexer with an FM discriminator for chirp reduction and wavelength locker in a filter to produce a wavelength division multiplexed signal with reduced chirp. A partially frequency modulation laser signal is converted into a substantially amplitude modulation laser signal. This conversion increases the extinction ratio of the input signal and further reduces the chirp. A wavelength division multiplexing (WDM) method is used for transmitting high capacity information through fiber optics systems where digital information is carried on separate wavelengths through the same fiber. Separate transmitters normally generate their respective signals that are transmitted at different wavelengths. These signals are then combined using a wavelength multiplexer to transmit the high capacity information through the fiber optic system.

Abstract: An optical switch for routing arbitrary wavelengths between optical fibers in optical networks. The optical switch may include a highly wavelength dispersive element together with a spatially dispersive element to separate the wavelengths. Broadband switch inputs and outputs may be provided for adding and dropping arbitrary wavelengths at each node of the network. Fiber demultiplexers and multiplexers may also be used to reduce the impact of mirror array yield on switch functionality.

Abstract: A multi-wavelength light source unit for optical communication system is disclosed. The light source includes a demultiplexer for demultiplexing a multiplexed light signal into a plurality of lights having different wavelengths and a multiplexer that receives the demultiplexed lights and multiplexes the demultiplexed lights into the multiplexed light signal. Input ports of the multiplexer are respectively port-to-port connectable to each one of a plurality of output ports of the demultiplexer. The light source unit includes a plurality of semiconductor optical amplifiers amplifying the demultiplexed lights output form the demultiplexer, and a plurality of beam splitters for splitting the amplified demultiplexed lights into two parts, so as to provide the respective input ports of the multiplexer with a split part of the lights, while to transmit the other part of the lights out of the beam splitters.

Abstract: A device for tailoring the chromatic dispersion of a multi-channel light signal is proposed. The device includes at least two waveguides coupled in a cascade, each provided with a spatially distributed optical filter. The group delay response of the filters is designed so that the group delay of each channel of the light signal can be tuned independently of the others, and an appropriate tuning mechanism is provided for this purpose. The device may advantageously be used as a flexible dispersion compensator.

Abstract: A recirculating optical delay line 30 has a laser 32 controlled by wavelength control 33 so as to vary the wavelength of radiation over time to provide a first input 34 to an optical modulator 35. The modulator 35 modulates the intensity of the first input 34 with a pulsed electromagnetic frequency signal 36 to produce a pulsed modulated optical signal 39. The signal 39 passes through an optical coupler 40 into a delay loop 41 having a delay fibre 44 arranged to delay the signal 39 for a predetermined duration. The wavelength control 33 is arranged to vary the first input 35 so as to ensure that overlapping pulses of the signal 39 in the delay loop 41 are at different wavelengths, thereby inhibiting optical mixing effects between the overlapping pulses.

Abstract: An arrangement for dispersing light comprises a blazed diffraction grating and a mirror. The blazed diffraction grating comprises a grating plane and a multiplicity of blazed facets. Each blazed facet is oriented at a blaze angle to the grating plane. The mirror couples to the blazed diffraction grating and is oriented parallel to the blazed facets. The arrangement permits a highly dispersive optical function in a very compact structure with low polarization dependent loss.

Abstract: A temperature sensing and control method and apparatus. In one aspect of the present invention, an apparatus according to the teachings of the present invention includes an optical path disposed in semiconductor material. A four-terminal resistor is defined in the semiconductor material. At least a portion of the optical path is directed through the four-terminal resistor. The four-terminal resistor includes a first pair of terminals between which a probe current is to be injected. The four-terminal resistor also includes a second pair of terminals between which a voltage drop is to be measured so as to determine a resistance along the portion of the optical path directed through the four-terminal resistor. Temperature may be derived from the determined resistance of the four-terminal resistor. In one embodiment, the temperature of the semiconductor material may then be controlled with a heater in response to the derived temperature.

Abstract: Method and apparatus are contemplated for receiving from an input, an optical signal in a volume hologram comprising a transfer function that may comprise temporal or spectral information, and spatial transformation information; diffracting the optical signal; and transmitting the diffracted optical signal to an output. A plurality of inputs and outputs may be coupled to the volume hologram. The transformation may be a linear superposition of transforms, with each transform acting on an input signal or on a component of an input signal. Each transform may act to focus one or more input signals to one or more output ports. A volume hologram may be made by various techniques, and from various materials. A transform function may be calculated by simulating the collision of a design input signal with a design output signal.

Abstract: A time-spreading and wavelength-hopping optical encoder spreads each pulse in a modulated optical pulse signal into a predetermined pulse train including pulses with different wavelengths. The last pulse in the pulse train is delayed from the first pulse in the pulse train by an interval that is longer than the pulse period of the modulated optical pulse signal. Interference is avoided by dividing the pulse train into successive delay groups that are equal in length to the pulse period of the modulated data pulse signal, and having each wavelength appear in only one delay group. If encoders producing differently structured pulse trains are used in an optical multiplexer, interference is avoided by having the same wavelength appear only at different positions within the delay groups of different pulse trains. Long delays can be used to multiplex a relatively large number of channels, even at high transmission rates.

Abstract: A wavelength division element includes a first filter and a second filter. The first filter has incident angle-to-transmission wavelength characteristics and separates multiplexed lights in a plurality of wavelength bands into first lights that are in a first wavelength band and first reflected lights. The first filter allows the first lights to pass through in a first direction and reflects the first reflected lights in a second direction. The second filter is located in the second direction and separates the first reflected lights into second lights that are in a second wavelength band and second reflected lights. The second filter allows the second lights to pass through in a third direction and reflects the second reflected lights in a fourth direction.

Abstract: An optical demultiplexer having at least one Bragg diffraction grating for minimizing crosstalk on the sides of transmitting and receiving optical signals, as well as an optical communication module using the optical demultiplexer. The optical demultiplexer has first and second waveguides arranged adjacent each other in a predetermined section in order to perform mode coupling, so that the optical signals input through one end of the first waveguide are transmitted to a light receiving element through the second waveguide, and in which output light waves inputted through the other end of the first waveguide are output through the one end of the first waveguide. A first Bragg diffraction grating is formed on the second waveguide and haa wavelength selectivity, for minimizing crosstalk by transmitting a reception wavelength of the optical signals at about 100% and by reflecting a wavelength of the output light waves at about 100%.

Abstract: A coupler-multiplexer permutation switch (CMPS) integrates multiplexng and switching functions on a single substrate. It has a single-mode/multi-mode backward coupler followed by a digital optical switch (DOS). In the CMPS, the single-mode waveguide channels are phase-matched through a grating with the corresponding, backward-propagating modes of a multi-mode waveguide. The different modes are subsequently separated in a digital optical switch. Different permutations are obtained by electronically controlling an effective-index distribution of DOS output waveguides.

Abstract: In an optical grating device, a grating arrangement receives different wavelength output signals from a plurality of radiation sources at input ports thereof, and generates therefrom a multiplexed wavelength output signal at a zero diffraction order output port of the grating arrangement. Additionally, the gating arrangement generates at least one predetermined wavelength output signal at one of a group consisting of a separate predetermined location in an at least one of a symmetric non-zero diffraction order of the grating arrangement, within the grating arrangement itself, and a combination thereof. A separate power tap is coupled to detect the power of a separate one of the at least one predetermined wavelength output signal from the grating arrangement.

Abstract: The invention relates to a planar lightwave circuit including a two stage optical filter for use in a bi-directional transceiver. A first stage includes a non-dispersive optical filter, which enables light within in a certain wavelength range, e.g. a signal channel from a laser source, to be launched onto an input/output waveguide, while light within another wavelength range, e.g. one or more detector channels, will be directed from the input/output waveguide to a second stage. The second stage includes a reflective diffraction grating with a higher resolution than the first stage providing passbands 2 to 5 times thinner than the first stage.

Abstract: A method and apparatus are disclosed for temporally shifting one or more packets using wavelength selective delays. The header information associated with each packet, together with a routing algorithm, routing topology information and internal OPTR state, is used to route each packet to the appropriate destination channel and to make timing decisions. A wavelength server generates optical control wavelengths in response to the timing decisions. A generated optical control wavelength is used to adjust the wavelength of a given packet tray and thereby introduce a wavelength selective delay to the packet tray to align packet trays or to shift one or more packet trays to avoid a collision. The wavelength of the packet tray is converted to a control wavelength corresponding to an identified delay, irrespective of the initial channel upon which the packet tray was received. At the output stage of the packet tray router, the packet tray wavelength can be converted to any desired output channel wavelength.

Abstract: In an optical wavelength division multiplexed access system, a center unit (OSU) and n optical network units (ONUs) are connected together via a wavelength splitter and optical fiber transmission lines, and downstream optical signals from the OSU to the ONUs and upstream optical signals from the ONUs to the OSU are transmitted in both directions, the wavelength spacing ??d (optical frequency spacing ?fd) of the downstream optical signals is set to twice or more the wavelength spacing ??u (optical frequency spacing ?fu) of the upstream optical signals, each ONU transmits an upstream optical signal whose optical spectral width is twice or more ??u (?fu), and the wavelength splitter spectrum slices the upstream signals transmitted from the ONUs into wavelengths (optical frequencies) whose optical spectral widths are mutually different within ??u (?fu), and wavelength-division multiplexes them and transmits to the OSU.

Abstract: Apparatus and method for spectral-beam combining light from a plurality of high-power fiber lasers that, in some embodiments, use two substantially identical diffraction gratings in a parallel, mutually compensating configuration to combine a plurality of separate parallel input beams each having a slightly different successively higher wavelength into a single output beam of high quality. In other embodiments, a single diffraction grating is used to combine a plurality of different wavelengths, wherein the input laser beams are obtained from very narrow linewidth sources to reduce chromatic dispersion. In some embodiments, diagnostics and adjustments of wavelengths and/or positions and angles are made dynamically in real time to maintain the combination of the plurality input beams into a single high-quality output beam.

Abstract: An optical time delay apparatus comprises: a multi-wavelength optical source; a diffractive element set imparting a wavelength-dependent delay on signals routed from the source to a 1×N optical switch; and N diffractive element sets routing signals from the 1×N switch to an output port. The optical propagation delay between the source and the output port varies according to the operational state of the source and the 1×N switch. A photodetector may receive the time-delayed signal at the output port.

Abstract: A slab optical waveguide confines in one transverse dimension optical signals propagating in two dimensions therein, and has a set of diffractive elements collectively arranged so as to exhibit positional variation in amplitude, optical separation, or spatial phase. The diffractive elements are collectively arranged so as to apply a transfer function to an input optical signal to produce an output optical signal. The transfer function is determined at least in part by said positional variation in amplitude, optical separation, or spatial phase. The waveguide and diffractive elements are arranged so as to confine only one of the input and output optical signals to propagate in the waveguide so that the optical signal thus confined is successively incident on the diffractive elements, while the other optical signal propagates unconfined by the waveguide in a direction having a substantial component along the confined dimension of the waveguide.

Abstract: A reconfigurable add-drop multiplexer (R-OADM) comprises an array of channel waveguides coupling two groups of diffractive element sets on a slab waveguide. The channel waveguides include switchable reflectors or are coupled to other channel waveguides by optical switches. Switching a reflector to reflect or setting a switch to couple two waveguides results in a corresponding wavelength channel being added or dropped. Switching the reflector to transmit or setting the switch to uncouple the two waveguides allows the corresponding wavelength channel to pass through the R-OADM without being added or dropped.

Abstract: A single free-beam region for coupling electromagnetic radiation in and out is provided in order in the case of an AWG coupler for spectrally separating electromagnetic radiation to achieve a more stable thermal characteristic and a space-saving layout.

Abstract: The present invention relates to a diffractive grating member and to an optical communication module. The optical communication module includes a semiconductor laser; a coupling optical system for coupling a light flux with a wavelength of ?1 emitted by the semiconductor laser to an optical fiber; and two light-receiving elements for receiving at least two light fluxes each having wavelengths ?2 and ?3 emitted from an end surface of the optical fiber. The coupling optical system has a diffractive structure, and the coupling optical system changes paths of light fluxes each having wavelengths ?1, ?2 and ?3 into relatively different directions such that the light flux with the wavelength ?1 emitted by the semiconductor laser enters into the optical fiber and each of the at least two light fluxes each having the wavelengths ?2 and ?3 enters into each of the two light-receiving elements.

Abstract: An optical wavelength grating coupler incorporating one or more distributed Bragg reflectors (DBR) or other reflective elements to enhance the coupling efficiency thereof. The grating coupler has a grating comprising a plurality of scattering elements adapted to scatter light along a portion of an optical path, and the one or more DBRs are positioned with respect to the grating such that light passing through the grating towards the substrate of the grating coupler is reflected back by DBRs toward the grating. The DBR comprises a multilayer stack of various materials and may be formed on the substrate of the grating coupler. The grating coupler may include a gas-filled cavity, where the cavity is formed by a conventional etching process and is used to reflect light toward the grating. The grating coupler may also incorporate an anti-reflection coating to reduce reflective loss on the surface of the grating.

Abstract: A spectrometer using a diffraction grating includes a light-incident portion including an incident-side optical waveguide emitting a light beam that includes a plurality of wavelength components and that approximates a Gaussian beam, and a collimating lens that is arranged on an emission side of the incident-side optical waveguide and that converts the light beam approximating a Gaussian beam that is emitted from the incident-side optical waveguide into a substantially collimated light beam; a diffraction grating having grooves on its surface, on which the light beam that has been converted into the substantially collimated light beam by the collimating lens is incident, the diffraction grating spectrally separating the light beam by emitting light beams whose emission direction depends on their wavelength; and a light-emitting portion having a plurality of focusing lenses that respectively condense the light beams that have been spectrally separated by the diffraction grating.

Abstract: A method and an apparatus are provided to demultiplex an optical signal having a plurality of channels at a predetermined channel spacing having demultiplexing means with a frequency spacing larger than the predetermined channel spacing for receiving the optical signal and for dividing the optical signal by wavelength into a plurality of wavelength streams broader than the predetermined channel spacing, time domain demultiplexing means for receiving one of the plurality of wavelength streams and for dividing the one of the plurality of wavelength streams into a plurality of time domain demultiplexed wavelength streams, and optical filtering means for demultiplexing one of the plurality of time domain demultiplexed wavelength streams into a single channel. Advantageously, splitting means are provided to split the optical signal into sub-signals before launching them into the demultiplexing means.

Abstract: The present invention is generally directed to optical signal devices that monitor the quality of an optical signal in a wavelength division multiplexing system by evaluating the information in the different wavelength channels.

Abstract: A novel wavelength routing apparatus is disclosed, which uses a diffraction grating to separate a multi-wavelength optical signal from an input port into multiple spectral channels; a channel-interleaving assembly (e.g., an array of prisms) to interleave the spectral channels into two channel groups; and an “augmented relay system” to relay the interleaved channel groups onto two separate arrays of channel micromirrors, respectively. The channel micromirrors are individually controllable and pivotable to reflect the spectral channels into multiple output ports. As such, the inventive wavelength routing apparatus is capable of routing the spectral channels on a channel-by-channel basis and coupling any spectral channel into any one of the output ports.

Abstract: The invention relates to a double-grating subtractive-dispersion optical channel multiplexer/demultiplexer for combining or separating optical channels and providing the output channels with a flat-top response. The FSR of the first grating is substantially equal to the channel spacing of the optical channels, such that the emission from the first grating achieves a cyclic offset of incidence angle into the second grating of the system.