Abstract: For conventional cipher communications based on the principles of quantum mechanics, the photon number per signal needs to be controlled below 1 or to a mesoscopic level in order to make quantum-mechanical properties remarkable. This invention is intended to provide a quantum-mechanical communications' method that is practical even with a macroscopic number of photons. Antisqueezed light is transmitted using a random sender basis. The legitimate recipient can use a secret key to know the random sender basis, and thus to receive the information accurately without being affected by antisqueezing. However, because eavesdroppers unknowing of the sender basis must use haphazard bases in an attempt to receive the signals, the eavesdroppers are significantly affected by antisqueezing and the respective signal bit-error-rates are increased. This makes eavesdropping impossible, thus ensuring secure communications between the legitimate senders and recipients.

Abstract: An optical module socket includes a base on which an optical module is mounted; descend/ascend means which is ascendably and descendably provided in the base and on which the optical module is mounted; holding means for holding the optical module in a predetermined state; pogopins provided in the base to connect with leads of the optical module; and positioning means of optical transmission means which are provided in the holding means and the descend/ascend means and which position, to the optical module, an optical connector to be connected to the optical module.

Abstract: An example of an optical source includes a VCSEL and a filter. The filter is positioned on the VCSEL and is configured and arranged such that an input to the filter from the VCSEL comprises a directly modulated optical data signal, and a corresponding output of the filter comprises an amplitude and/or phase modulated optical data signal, optimized for long-distance transmission in the optical fiber.

Abstract: A system and method for generating an optical return-to-zero signal. The system includes an electro-optical conversion system. The electro-optical conversion system is configured to receive an input electrical non-return-to-zero signal, process information associated with the input electrical non-return-to-zero signal, and generate a first electrical signal and a second electrical signal based on at least information associated with the input electrical non-return-to-zero signal. Additionally, the electro-optical conversion system is configured to delay a second electrical signal with respect to the first electrical signal by a predetermined period of time, process information associated with the first electrical signal and the delayed second electrical signal, and generate an output optical return-to-zero signal based on at least information associated with the first electrical signal and the delayed second electrical signal.

Abstract: An optical transmitter includes a drive laser, a 1×N splitter, and an array of modulators. The 1×N splitter is coupled to split a beam from the drive laser into separated beams, and the modulators modulate the respective beam to represent respective data signals that are transmitted in parallel. Embodiments of the transmitter can provide high data rate communications at low cost by eliminating the need for an array of isolators and eliminating the need for high quality AR coatings. Additionally, an integrated optical circuit containing the modulator array does not require an array of lasers and can be fabricated at higher yields and lower costs.

Abstract: A bias-control circuit that provides operating point control for a Mach-Zehnder modulator experiencing optical absorption at their interferometric arms. The bias control circuit generates compensation signals that are used to counter the thermally induced index shifts as a result of absorption. In addition, an operating point with desirable transmitter characteristics can also be arbitrarily chosen by over-compensating or under-compensating thermal effects.

Abstract: The infrared LED of an IrDA module transmits IR energy with a peak wavelength (for example, 875 nm) appropriate for IrDA communication. This peak wavelength is lower than is the wavelength (for example, 940 nm) used in ordinary IR remote controls (RC). The IrDA LED does, however, transmit some energy at the wavelength of the peak sensitivity of an RC receiver. When making an IrDA transmission, the IrDA LED is driven with a lower amount of current. When making an RC transmission, the IrDA LED is driven with an increased amount of current such that higher wavelength emissions received by the RC receiver are of adequate power to realize RC communication. A passive circuit is disclosed for automatically increasing IrDA LED current during RC transmissions. The circuit involves an inductor that shunts current around a current-limiting resistor used to limit LED drive current.

Abstract: An optical system comprising a frequency modulated laser source adapted to produce a frequency modulated optical beam, an optical spectrum reshaper (OSR) adapted to receive the frequency modulated optical beam from the laser source and convert it into an amplitude modulated optical beam, a focusing lens adapted to receive the amplitude modulated optical beam from the OSR and focus the same, and an optical fiber adapted to receive the amplitude modulated optical beam from the focusing lens and transmit an optical signal; characterized in that the OSR has a central axis, the focusing lens has a central axis, and the optical fiber has a central axis, with the central axis of the optical fiber being laterally offset from at least one of the central axis of the OSR and the central axis of the focusing lens so as to effect spatial filtering and thereby generate the desired optical transmission characteristics for the resulting optical signal in the optical fiber.

Abstract: An optical transmitter is disclosed including an optical signal source generating a frequency modulated signal encoding data. An optical spectrum reshaper is positioned to receive the frequency modulated signal and converts the frequency modulated signal into a reshaped signal having increased amplitude modulation relative to the frequency modulated signal. A third-order dispersive element is positioned to receive the reshaped signal and is adapted to impose third-order dispersion on the reshaped signal to generate a compensated signal having third-order dispersion effective to compensate for second-order dispersion caused by an optical fiber positioned between the optical transmitter and a receiver.

Abstract: A wireless communication system, a wireless transmitting apparatus, and a wireless receiving apparatus which can be applied to all types of light sources and can be applied to a variety of fields, provided with a medium forming an information transmission source, a general light source made of for example a lamp or the sun or another natural light source or artificial light source, a wireless transmitting apparatus for making the polarization of the light from the light source uniform and controlling the polarization plane of an infrared ray, visible ray, UV ray, or other light (modulating the light in polarization) so as to superimpose other information invisible to the human eye on visual information due to general reflected light and transmitting the same as an optical wireless signal, and a wireless receiving apparatus for receiving the optical wireless signal transmitted from the wireless transmitting apparatus and able to determine a change in orientation of the polarization plane of the light as inform

Abstract: In a radio optical fusion communication system with the integration of an optical fiber transmission path and a radio propagation path, wherein by first and second light sources, an intermediate-frequency signal generating means for generating a modulating signal at an intermediate frequency band, a modulator for modulating an optical signal from the first light source into an SSB modulated optical signal using the intermediate-frequency signal, and an optical mixer for mixing the modulated optical signal with the optical signal from the second light source to obtain an optical transmission signal in a base station, the frequency of either of the optical signals is controlled such that the difference in frequency between the optical signals is a desired frequency of a modulated radio signal, thus switching the frequency channel of the modulated radio signal in the radio propagation path.

Abstract: A nano device includes an array of cells disposed in rows and columns and constructed over a substrate, and an optical circuit disposed over the substrate, wherein the optical circuit is formed by nano elements in a self-assembled process.

Abstract: The present invention is directed to providing anew illuminating light communication system capable of transmitting large-capacity data at high speed. A transmitting device 1 emits light modulated depending on data to be transmitted from an organic EL light source 4. A receiving device 2 receives the modulated light emitted from the organic EL light source 4 and converts the received modulated light into an electric signal, and demodulates the data from the electric signal obtained by the conversion.

Abstract: A process for all-optically switching an incoming optical signal having at least a data packet is provided. The data packet including at least an address bit in its header, and the process includes receiving the data packet; processing the header optically; storing the decision made during the processing of the header; and switching the whole incoming data packet dependent upon the decision.

Abstract: A carrier signal extraction system for suppressing and extracting a carrier signal component and transmitting a double sideband component includes a polarized light source for transmitting a polarized light signal output; a polarization modulator with a first input coupled to the polarized light signal output and a second input for adding a modulation signal to the polarized light signal, thereby generating a polarization modulated light output; and a polarizing element having an input coupled to the polarization modulated light output for suppressing and extracting the carrier signal component and preferentially transmitting a double sideband component of the polarization modulated light output.

Abstract: In accordance with an example embodiment of the present invention, an apparatus is provided, comprising a portion of semiconductor comprising an optical transmitter and an optically sensitive structure, wherein the semiconductor is covered with an interference filter at least in a first area comprising at least part of the optical transmitter and a second area comprising at least part of the optically sensitive structure, and wherein the interference filter of the first area is substantially optically separate from the interference filter of the second area.

Abstract: The present invention provides an apparatus for multiplexing a plurality of light waves with different wavelengths. The apparatus includes a laser sub-assembly, a multiplexer sub-assembly, and a receptacle sub-assembly. The laser sub-assembly includes a plurality of lasers for radiating a plurality of light waves of different wavelengths. The plurality of light waves are multiplexed in the multiplexer sub-assembly. The multiplexed light waves are coupled to an optical fiber by the receptacle sub-assembly.

Abstract: An optoelectronic package that employs a spacer tool system to properly align an optical component within the device is disclosed. In one embodiment, the package includes a mounting surface, and an optical component positioned on the mounting surface at a predetermined distance from a reference point. The optical component is positioned at the predetermined distance by a spacer tool, wherein the spacer tool is interposed between the optical component and a spacer tool mount during optical component positioning. The spacer tool is of a length that corresponds with the predetermined distance between the optical component and the reference point.

Abstract: A disclosed apparatus comprises a guiding element and a nonlinear element. The guiding element guides optical input signals, at least one of which is phase-modulated, to an interference area where such signals meet and interfere. The resulting interference signal is nonlinearly discriminated by the nonlinear element to produce an optical output signal that can be amplitude- or phase-modulated according to the phase modulation of the input signals. The invention also includes related methods and photonic logic gates.

Abstract: An apparatus for handling an optical signal includes: an optical transmitting unit transmitting the optical signal from an input locus to an output locus. The optical transmitting unit includes a plurality of optical transmitting sections. Each respective optical transmitting section of the plurality of optical transmitting sections has a respective length and a respective attenuation gradient to establish a respective length-and-attenuation gradient configuration. Each respective optical transmitting section effects attenuation of the optical signal according to its respective length-and-attenuation gradient configuration.

Abstract: A first light feedback element is arranged at an optical distance L1 from a front facet of a semiconductor laser from which an output light is emitted on an optical path of the output light. An i-th light feedback element is arranged at an optical distance Li from the front facet on the optical path of the output light, where i=2 to n, n is a positive integer not less than 2, and Li>L1. L1 and Li satisfies ((M?1)+0.01)<(Li/L1)<(M?0.01), where M is a positive integer not less than 2, satisfying (M?1)<(Li/L1)?M.

Abstract: An optical transmitter produces electromagnetic radiation (e.g., light) of at least one frequency (e.g., at a particular color frequency) by utilizing a resonant structure that is excited by the presence a beam of charged particles (e.g., a beam of electrons) where the electromagnetic radiation is transmitted along a communications medium (e.g., a fiber optic cable). In at least one embodiment, the frequency of the electromagnetic radiation is higher than that of the microwave spectrum.

Abstract: A single wavelength fiber-optic communication system that mixes an Ethernet signal with a radio frequency signal is disclosed. The system includes an Ethernet signal module, a radio frequency signal module, a mixer module and a receiver module. The Ethernet signal module provides an Ethernet signal. The radio frequency signal module provides a radio frequency signal. The mixer module provides an optical mixed signal by means of mixing the Ethernet signal with the radio signal at a single wavelength. The receiver module transforms the optical mixed signal into the radio frequency signal and a digital signal that contains the Ethernet signal.

Abstract: An optical transmitter for an optical communication system is provided. Included in the transmitter is a first optical delay element configured to generate a second optical signal from a first optical signal. A second optical delay element is configured to generate a fourth optical signal from a second optical signal. An optical multiplexer is configured to combine the third and fourth optical signals to produce a fifth optical signal. Also included is an optical modulator configured to alter a pulse width of the fifth optical signal to generate a sixth optical signal. An optical delay controller is configured to control the first optical delay element and the second optical delay element based on the sixth optical signal.

Abstract: The present invention relates generally to an optical CDMA transmission system and method employing differential optical encoding and bipolar decoding. Differential encoding and bipolar decoding may be performed at the bit level, wherein differential phase encoding and decoding occurs on an entire composite signal. Differential encoding and bipolar decoding may also be performed at the chip level, wherein differential phase encoding and decoding occurs on individual spectral components of a given signal.

Abstract: This invention generally relates to an optical filter for a fiber optic communication system. An optical filter may be used, following a directly modulated laser source, and converts a partially frequency modulated signal into a substantially amplitude modulated signal. The optical filter may compensate for the dispersion in the fiber optic transmission medium and may also lock the wavelength of the laser source.

Abstract: A fiber optic communication system comprising: an optical signal source adapted to receive a binary base signal having a bit period T, and generate a first signal, wherein the first signal is frequency modulated; and an optical spectrum reshaper (OSR) adapted to reshape the first signal into a second signal, wherein the second signal is amplitude modulated and frequency modulated; characterized in that: the optical signal source is a laser in which frequency modulation is generated by modulating the loss of the laser cavity. A method for transmitting a signal, comprising: receiving a binary base signal having a bit period T, and generating a first signal, wherein the first signal is frequency modulated; and reshaping the first signal into a second signal, wherein the second signal is amplitude modulated and frequency modulated; characterized in that: the first signal is frequency modulated by using a laser in which frequency modulation is generated by modulating the loss of the laser cavity.

Abstract: A fiber optic communication system is disclosed having an optical signal source adapted to produce an amplitude and frequency modulated signal encoding binary data wherein high intensity 1 bits are red shifted relative to lower intensity 0 bits. The amplitude and frequency modulated signal is transmitted through a semiconductor optical amplifier (SOA), which may operate in saturation. An optical spectrum reshaper (OSR) is adapted to reshape the output of the SOA.

Abstract: A method and an apparatus for pulse-amplitude equalization of rational harmonic mode-locked optical pulses provides modulation voltages greater than a switching voltage of a dual-electorde Mach-Zehnder modulator to electrodes of the Mach-Zehnder modulator, so that rational harmonic mode-locked optical pulses experience the same transmission coefficient through the Mach-Zehnder modulator, to thereby achieve amplitude-equalized rational harmonic mode-locked optical pulse trains.

Abstract: An optical transmitter has a resonance wavelength characteristic that varies with the refractive index of the optical transmitter. The optical transmitter receives a narrow band injected wavelength signal from an incoherent light source. The controller substantially matches a resonant wavelength of the optical transmitter to the wavelength of the injected wavelength signal by changing the refractive index of the optical transmitter to substantially match the resonant wavelength of the optical transmitter and the wavelength of the injected wavelength signal. A detector measures a parameter of the optical transmitter to provide a feedback signal to a controller to determine when the resonant wavelength of the optical transmitter and the wavelength of the injected wavelength signal are substantially matched.

Abstract: Methods and apparatus are described for modulating an optical signal using electroabsorption in conjunction with an optical interferometer. Phase-shift keying modulation can be achieved with lower amplitude modulator drive signals than conventional methods by splitting the signal to be modulated into multiple optical modes and interferometrically combining the modes after modulating at least one of the modes with an EAM. Using the present invention, the extinction ratio performance of ASK can be significantly improved for a given drive voltage or a desired extinction ratio can be achieved with a substantially lower drive voltage. Hence, the elecro-optic bandwidth of EAMs can be enhanced by overcoming the trade-off relationship between extinction ratio and bandwidth. Furthermore, the present invention can be used to generate other modulation formats, such as QPSK or QAM, with much lower drive voltages, thereby reducing the cost and power consumption of the high-speed drive electronics for the modulation.

Abstract: A transmitter on an integrated circuit chip is disclosed that employs a laser, modulator, and a dispersion compensator module and a modulator for overcoming chromatic dispersion and polarization dependent loss effects. With the present invention, the dispersion compensator module is placed on a chip, either integrated or monolithic, for operation with a laser and a modulator without the need to compensate for dispersion within a separate unit that is not part of the chip. The dispersion compensator module can be implemented, for example, with a ring resonator, an etalon or a Mach-Zehnder interferometer. In a first aspect of the invention, the optical transmitter module of the present invention provides a cost-effective solution for upgrading from an existing optical network to a faster optical network, such as upgrading from a 2.5 Gbps to a 10 Gbps network.

Abstract: Monolithic single and/or dual detector structures are fabricated on the emitting surface of a VCSEL and/or on a lens or glass substrate configured to be positioned along the axis of emission of an optical light source. Each monolithic detector structure includes one or two PIN detectors fabricated from amorphous silicon germanium with carbon doping or amorphous germanium with hydrogen doping. The monolithic detectors may additionally include various metallization layers, buffer layers, and/or anti-reflective coatings. The monolithic detectors can be grown on 1550 NM VCSELs used in optical transmitters, including lasers with managed chirp and TOSA modules, to reduce power and real estate requirements of the optical transmitters, enabling the optical transmitters to be implemented in long-reach SFP+ transceivers.

Abstract: A robustly stabilized communication laser can output a multimode optical signal remaining aligned to a coordinate of a dense wavelength division multiplexing (“DWDM”) grid while responding to a fluctuating condition or random event, such as, without limitation, exposure to a temperature fluctuation, stray light, or contamination. Responsive to the fluctuating condition, energy can transfer among individual modes in a plurality of aligned longitudinal modes. Modes shifting towards a state of misalignment with the DWDM coordinate can attenuate, while modes shifting towards a state of alignment can gain energy. Fabrication processes and systems and light management, such as beam steering, epoxy scaffolds, spectral adjustments, mode matching, thermal expansion control, alignment technology, etc. can facilitate nano-scale control of device parameters and can support low-cost fabrication.

Abstract: A signal interface comprises a non-reciprocal device having a first port that accepts a first electrical signal and a second port that accepts a second electrical signal. The non-reciprocal device passes the second electrical signal through the first port without a phase shift and passes the first electrical signal through the second port with a 180 degrees phase shift. An optical modulator receives an optical signal at an optical input port, a second signal at a first and a second electrical input port, the first electrical signal at a third electrical input port, and the phase-shifted first electrical signal from the non-reciprocal device at a fourth electrical input port. The optical modulator transmits the second electrical signal to the first port of the non-reciprocal device without a phase shift and modulates the first electrical signal on the optical signal and providing the modulated optical signal at an optical output port of the optical modulator.

Abstract: An optical device for regenerating an optical clock, including an optical path provided between an input port to which signal light modulated at a frequency fs is supplied and an output port, and an optical loop optically coupled to the optical path. The optical loop includes an optical amplifier for compensating for a loss in the optical loop so that laser oscillation occurs in the optical loop, an adjuster for adjusting the optical path length of the optical loop so that the frequency fs becomes equal to an integral multiple of the reciprocal of a recirculation period of the optical loop, and a nonlinear optical medium for mode-locking the laser oscillation according to the signal light.

Abstract: An optical transmitter has a case. The case houses a laser beam generator, a lens, a cooler, and a high heat conductivity member. The lens concentrates the laser beam generated by the laser beam generator and leads the laser beam to an optical fiber. The high heat conductivity member is arranged between the laser beam generator and the lens and the cooler. The laser beam generator has higher heat conductivity than that of the case. The laser beam generator conveys the heat generated in the laser beam generator to the cooler.

Abstract: A WDM communication system having two optical-frequency comb sources (OFCSs) that are substantially phase-locked to one another, with one of these OFCSs used at a transmitter to produce a WDM communication signal and the other OFCS used at a receiver to produce multiple local-oscillator signals suitable for homodyne detection of the WDM communication signal received from the transmitter. In one embodiment, the transmitter has (i) a first OFCS adapted to generate a first frequency comb and (ii) an optical modulator adapted to use the first frequency comb to generate a WDM communication signal having at least two beacon lines for transmission to the receiver. The receiver has a second OFCS adapted to produce a second frequency comb having the beacon frequencies, with the phases of the corresponding comb lines being locked to the phases of the beacon lines of the received WDM signal.

Abstract: A fiber optic system comprising a modulated signal source coupled to a spectral filtering element characterized in that the bandwidth of the optical spectrum of the signal after the spectral filtering element is reduced relative to the optical bandwidth of the spectrum before the filtering element.

Abstract: An optical communication system which has an optical signal source adapted to receive a base binary signal and produce a first signal, said first signal being frequency modulated; and an optical spectrum reshaper adapted to reshape the first signal into a second signal, said second signal being amplitude modulated and frequency modulated in which the frequency characteristics of said first signal, and the optical characteristics of said optical spectrum reshaper, being such that the frequency characteristics of said second signal are configured so as to increase the tolerance of the second signal to dispersion in a transmission fiber.

Abstract: Systems and methods for encoding information in the topology of superpositions of helical modes of light, and retrieving information from each of the superposed modes individually or in parallel. These methods can be applied to beams of light that already carry information through other channels, such as amplitude modulation or wavelength dispersive multiplexing, enabling such beams to be multiplexed and subsequently demultiplexed. The systems and methods of the present invention increase the number of data channels carried by a factor of the number of superposed helical modes.

Abstract: A fiber optic communication system comprising: an optical signal source adapted to receive a binary base signal having a bit period T, and generate a first signal, wherein the first signal is frequency modulated; and an optical spectrum reshaper (OSR) adapted to reshape the first signal into a second signal, wherein the second signal is amplitude modulated and frequency modulated; characterized in that: the frequency excursion of the first signal is adjusted such that the frequency excursion is substantially equal to the ratio of the bit period of the digital base signal to total dispersion of the transmission fiber, whereby to increase the tolerance of the second signal to dispersion in a transmission fiber.

Abstract: A fiber optic communication system, comprising: an optical signal source adapted to produce a frequency modulated signal; and an optical spectrum reshaper adapted to receive the frequency modulated signal and output a substantially amplitude modulated signal; wherein the optical spectrum reshaper limits the bandwidth of the frequency modulated signal.

Abstract: An optical demodulator and accompanying method(s) that demodulates a DQPSK signal employing a single optical delay interferometer comprising a free-space Michelson interferometer having two optical paths, connected to a 1×2 coupler. Positioned within an arm of the Michelson interferometer is a phase shifter that produces a phase difference of ?/2 between the two paths. The resulting demodulator is compact, reliable, and may be constructed to be substantially immune from undesirable thermal sensitivities.

Abstract: A method and system is provided that is capable of controlling transmit power to achieve a desired OSNR at a receive endpoint. The system utilizes the fact that the aggregate power for a plurality of channels is controllable between a transmission point and a receive point in the network, and uses this characteristic to coarsely adjust transmission powers in the network to achieve desired OSNR results.

Abstract: An all optical network for optical signal traffic has at least a first ring with at least one transmitter and one receiver. The first ring includes a plurality of network nodes. At least a first add/drop broadband coupler is coupled to the first ring. The broadband coupler includes an add port and a drop port to add and drop wavelengths to and or from the first ring, a pass-through direction and an add/drop direction. The first add/drop broadband coupler is configured to minimize a pass-through loss in the first ring and is positioned on the first ring.

Abstract: The infrared LED of an IrDA module transmits IR energy with a peak wavelength (for example, 875 nm) appropriate for IrDA communication. This peak wavelength is lower than is the wavelength (for example, 940 nm) used in ordinary IR remote controls (RC). The IrDA LED does, however, transmit some energy at the wavelength of the peak sensitivity of an RC receiver. When making an IrDA transmission, the IrDA LED is driven with a lower amount of current. When making an RC transmission, the IrDA LED is driven with an increased amount of current such that higher wavelength emissions received by the RC receiver are of adequate power to realize RC communication. A passive circuit is disclosed for automatically increasing IrDA LED current during RC transmissions. The circuit involves an inductor that shunts current around a current-limiting resistor used to limit LED drive current.

Abstract: An optical receiver includes a first light receiving element to convert an optical signal to an electric signal and to output the electric signal from one end. A light receiving element row is connected to the other end of the first light receiving element to supply electric power to the first light receiving element. The light receiving element row includes a plurality of second light receiving elements connected in series.

Abstract: A fiber optic communication system for receiving an electronic digital data signal and transmitting the same, comprising an optical signal source adapted to receive the digital data signal and to produce a frequency modulated optical signal from a directly modulated semiconductor laser; an optical spectrum reshaper adapted to convert the frequency modulated optical signal into an amplitude modulated optical signal; and compensation apparatus for compensating for the adverse effects of the thermal chirp normally induced in the frequency modulated optical signal by modulating the semiconductor laser with the electronic digital data signal.

Abstract: A light-emitting module outputting laser beam emitted from a semiconductor light-emitting element via a lens, the light-emitting module includes a first main plane, a mount portion on the first main plane that mounts the semiconductor light-emitting element, a lens holding portion that holds the lens so that a light axis of the lens corresponds to a reference line crossed at right angles to the first main plane, a semiconductor light-receiving element that receives the laser beam reflected by the lens out of the laser beam emitted from the semiconductor light-emitting element. The semiconductor light-receiving element is positioned on the light axis of the lens and the semiconductor light-emitting element is provided away from the light axis of the lens.