Abstract: Coded light has been proposed to enable advanced control of light sources and transmit information using light sources. An assignment for the identification frequencies of light sources enables more unique frequencies to be assigned, i.e. more light sources to be uniquely identified in the system. An available frequency band is divided into non-uniform frequency regions and frequencies are selected from a set of uniformly spaced frequencies in the non-uniform frequency regions. A receiver is based on a successive approach and is enabled to analyze higher harmonics of the received light signals. The light contributions are successively estimated group by group.

Abstract: A system and methods are provided for converting a first temporally short and spectrally broad optical pulse into a train of spectrally narrow and distinct optical pulses. This involves receiving, on a first I/O channel, the first optical pulse associated with a plurality of wavelengths and performing wavelength division demultiplexing on the first optical pulse at an optical unit housed on an optical chip to output a plurality of second optical pulses on different ones of a plurality of second I/O channels, each of the second optical pulses associated with a unique wavelength range from the first optical pulse. This also involves receiving the second optical pulses at loop mirrors in the second I/O channels, wherein the second I/O channels are patterned as waveguides in the optical chip and reflecting, at the loop mirrors, the second optical pulses back to the optical unit.

Abstract: Consistent with the present disclosure, data, in digital form, is received by a transmit nodes of an optical communication, and converted to analog signal by a digital-to-analog converter (DAC) to drive a modulator. The modulator, in turn, modulates light at one of a plurality of wavelengths in accordance with the received data. The modulated light is then transmitted over an optical communication path to a receive node. At the receive node, the modulated optical signal, as well as other modulated optical signals are supplied to a photodetector circuit, which receives additional light at one of the optical signal wavelengths from a local oscillator laser. An analog-to-digital converter (ADC) is provided in the receive node to convert the electrical signals output from the photodetector into digital form. The output from the ADC is then filtered in the electrical domain, such that optical demultiplexing of individual channels is unnecessary.

Abstract: In a Wavelength-Division-Multiplexed Passive Optical Network (WDM-PON) utilizing a conventional downstream optical signal reusing method, there is an inventory problem that different optical transmitter types need to be provided for the operation, management, replacement, etc. of a system. A WDM-PON system according to the present invention, includes: a seed light (SL) unit generating a seed light whose wavelength intervals and center wavelengths are adjusted using at least one seed light source; an optical line terminal (OLT) receiving the wavelength-multiplexed seed light from the seed light unit, transmitting a downstream optical signal to a subscriber of the WDM-PON, and receiving a upstream optical signal from the subscriber; and an optical network unit (ONU) receiving the downstream optical signal from the OLT, flattening and modulating the downstream optical signal with upstream data so that the downstream optical signal is reused for carrying upstream data.

Abstract: A substantially 400 Gb/s optical transceiver includes a substantially 400 Gb/s optical transmitter which includes a set of four substantially 100 Gb/s tunable optical transmitters, each transmitting a substantially 100 Gb/s optical signal in a wavelength division multiplexed form over four channel wavelengths selected such that the resulting 16 channel wavelengths are different from each other and are suitable for WDM, and an optical transmission interface including a set of four 1:4 wavelength division demultiplexers which are operative to demultiplex the substantially 100 Gb/s optical signals to produce substantially 25 Gb/s optical signals over each of the 16 different channel wavelengths, and a 16:1 wavelength division multiplexer which is operative to multiplex the substantially 25 Gb/s optical signals of the 16 different channel wavelengths to generate a substantially 400 Gb/s optical signal.

Abstract: Consistent with the present disclosure, data, in digital form, is received by a transmit nodes of an optical communication, and converted to analog signal by a digital-to-analog converter (DAC) to drive a modulator. The modulator, in turn, modulates light at one of a plurality of wavelengths in accordance with the received data. The modulated light is then transmitted over an optical communication path to a receive node. At the receive node, the modulated optical signal, as well as other modulated optical signals are supplied to a photodetector circuit, which receives additional light at one of the optical signal wavelengths from a local oscillator laser. An analog-to-digital converter (ADC) is provided in the receive node to convert the electrical signals output from the photodetector into digital form. The output from the ADC is then filtered in the electrical domain, such that optical demultiplexing of individual channels is unnecessary.

Abstract: A laser system includes an array of lasers that emit light at a number of different, fixed wavelengths. A group of optical transport systems connect to the laser system. Each of the optical transport systems is configured to modulate data signals onto the light from the laser system to create optical signals and transmit the optical signals on one or more optical fibers.

Abstract: In a Wavelength Division Multiplexed (WDM) all-optical network having optical nodes linked together by optical fibers carrying communication channels of separate wave-lengths, a method is applied in order to extend the size of the all-optical network. According to the method, a model is set up for the all-optical network in which a wavelength graph containing vertices and edges represents the physical effects of the nodes and links. After identifying a set of demand, an objective function is calculated expressing the total routing cost and total signal power demand of the channels. The minimum of the objective function returns the signal powers for each channel to be tuned.

Abstract: When using a wavelength multiplexing unit of a wavelength multiplexing optical transmission system in which a wavelength tunable type optical transmitter and a wavelength multiplexer having no wavelength selectivity are combined, undesired light that is not supposed to be flown into a wavelength channel may be mixed therein. A wavelength multiplexing unit includes: transmitters having functions of outputting signal lights of different wavelengths from each other and changing the wavelengths; band-limiting filters provided to each of the transmitters, which have functions of eliminating the lights out of bands from the signal lights outputted from the transmitters, and changing the center wavelengths of the bands; and a wavelength multiplexer including ports capable of inputting the lights of any wavelengths, which inputs signal lights from which the light out of the bands is eliminated by the band-limiting filters and multiplexes the signal lights.

Abstract: A system and a method for optical transmission are provided. The system includes a power combiner, a laser light source, a negative chirp modulator, and multiple transmission units. Each transmission unit corresponds to a frequency band and generates a first output signal in the frequency band based on orthogonal frequency-division multiplexing (OFDM). The frequency bands are not overlapped with each other. The power combiner is coupled to each transmission unit. The power combiner combines each of the first output signals to generate a second output signal. The negative chirp modulator is coupled to the power combiner and the laser light source. The negative chirp modulator performs negative chirp modulation on the laser light source with the second output signal to generate a light signal and outputs the light signal to an optical fiber.

Abstract: A dense wavelength-division-multiplexing (DWDM) system, comprising a plurality of laser transmitters, a wavelength division multiplexer (WDM) optically coupled to the laser transmitters and to an output optical transmission media, a coupler optically coupled to the output optical transmission media, an interferometric filter optically coupled to the coupler but not directly to the output optical transmission media, and a light reflector optically coupled to the interferometric filter and not directly to the output optical transmission media.

Abstract: System for connecting a plurality of digital subscribers to a data network, comprising a local part connected, by an optical fiber link, to a remote part. Said local part comprises a plurality of DSLAM line cards with xDSL over fiber transceiver that, in turn, comprise a plurality of xDSL lines comprising a modified analog front end which comprises an digital-analogue converter to transform a transmitted digital downstream signal into an analogue downstream signal; an oscillator which fixes an oscillation frequency for the xDSL line; a mixer, directly connected to the output to convert the analog downstream signal into the oscillation frequency; and a band pass filter centered at the oscillation frequency which filters the converted analog downstream signal.

Abstract: Methods and apparatuses to provide wavelength locked WDM Passive Optical Networks (“PONs”) are described. A first transceiver transmits a set of optical signals in a first direction along a wavelength channel. A second transceiver transmits another set of optical signals along the same wavelength channel in another direction. The wavelength of the first transceiver is locked using an optical power of the optical signals of the second transceiver. The wavelength of the second transceiver is locked using the optical power of the optical signals of the first transceiver. A WDM MUX/De-MUX is coupled between the first transceiver and the second transceiver. An in-line gain element can be coupled to the WDM MUX/De-MUX to amplify the optical signals. The first transceiver and the second transceiver operate in a saturated gain condition.

Abstract: An optical network unit (ONU) comprising a first optical fiber, a first optical circulator coupled to the first optical fiber, a first seed light injected laser coupled to the first optical circulator, wherein the first optical circulator is positioned between the first seed light injected laser and the first optical fiber, and a second seed light injected laser coupled to the first optical circulator and the first seed light injected laser, wherein the first optical circulator is positioned between the second seed light injected laser and the first optical fiber. Also disclosed is a method comprising receiving a seed light signal, amplifying the seed light signal using seed light injection locking, thereby producing an amplified seed light signal, and producing an optical signal using the amplified seed light signal and seed light injection locking, wherein the optical signal has about the same wavelength as the seed light signal.

Abstract: An external cavity laser array system may be used in a WDM optical system, such as a WDM-PON, for transmitting optical signals at multiple channel wavelengths. The system generally includes a plurality of laser emitters (e.g., gain chips) optically coupled to and separated from respective exit reflectors (e.g., tunable narrow-band reflectors), thereby forming an array of external cavity lasers with extended lasing cavities. The exit reflectors may be distributed Bragg reflectors (DBRs) located in the waveguides in an arrayed waveguide grating (AWG). The laser emitters emit a range of wavelengths including multiple channel wavelengths and the DBRs reflect a subset of channel wavelengths including at least a channel wavelength associated with the laser emitter such that lasing occurs at the subset of channel wavelengths. The AWG then filters the emitted laser light at the associated channel wavelengths.

Abstract: Method, apparatus and systems for a wavelength division multiplexing system operating at O-Band. The system includes a transmitter for wavelength division multiplexing digital O-band optical channels into a multiplexed optical signal, amplifying and transmitting the multiplexed optical signal, a fiber transmission span using constant intensity modulation and semiconductor optical amplification, and a receiver for receiving and amplifying the transmitted multiplexed optical signal and restoring the individual digital O-band optical signals. In an embodiment, the transmission span is a single mode fiber transmission span and in another embodiment includes an optical amplifier module coupled into the fiber transmission span. In another embodiment, the transmission span includes a length of O-band dispersion compensating fiber to reduce four-wave mixing. In another embodiment the system uses wavelength division multiplexing in combination with polarization interleaving.

Abstract: An optical transmitter for an optical communication system includes a light source that outputs optical signals having a plurality of wavelengths, and a wavelength control unit. The wavelength control unit receives an optical signal from the light source, resonates an optical signal having a first wavelength, modulates the optical signal of the first wavelength with a first transmission data signal to obtain an intensity modulated optical signal, and outputs the intensity modulated optical signal. The wavelength control unit may be integrally formed on a semiconductor substrate in which a high thermal conductivity material is used Alternatively, a trench that intercepts external heat may be formed in a boundary surface of the wavelength control unit, and may be filled with a low thermal conductivity material.

Abstract: A multi-wavelength optical transmission system includes a plurality of primary optical transmitters, each being configured to provide directly modulated analog optical signals at non-uniformly spaced apart wavelengths. An optical multiplexer having a plurality of optical input ports receives the analog optical signals from each of the plurality of primary optical transmitters and provides a wavelength division multiplexed signal over an optical fiber coupled at an output thereof. A spare optical transmitter is coupled to an input port of the optical multiplexer and, in response to detecting failure of a failed one of the plurality of primary optical transmitters, is tuned to provide a directly modulated analog optical signal at a spare wavelength that is selected as to be non-uniformly spaced relative to at least some of the non-uniformly spaced apart wavelengths according to tuning data.

Abstract: According to one embodiment, a system for transmitting an optical signal comprises a traffic distribution circuit configured to distribute traffic to a plurality of wavelength division multiplexer (WDM) modules. The system further comprises a first WDM module and a second WDM module. The first and second WDM modules each comprise a plurality of tunable optical transmitters, with each transmitter associated with a different wavelength band of a plurality of wavelength bands. Each transmitter in the first and second WDM modules is also tuned to transmit optical signals in channels included within the associated wavelength band of the transmitter. The first and second WDM modules each comprise a multiplexer configured to combine the optical signals transmitted from the plurality of transmitters into optical signals. The system further comprises a cyclic multiplexer configured to combine the optical signals from the first and second WDM modules into an optical output signal.

Abstract: A fiber output stabilizer according to an aspect of the invention stabilizes output light from a rare-earth doped optical fiber in which at least one kind of a rare-earth element is added to a core. The fiber output stabilizer includes: a monitoring light source that emits monitoring light having a wavelength shorter than that of excitation light exciting the rare-earth element; an optical multiplexer that multiplexes the monitoring light into the excitation light; an optical demultiplexer that demultiplexes the monitoring light passing through the rare-earth doped optical fiber; and a passing light detector that detects light intensity of the monitoring light from the optical demultiplexer.

Abstract: A transmitter for generating, starting from a data-packet traffic at input, flows of information to be conveyed via optical signals with different wavelengths towards a plurality of targets in a communications network, the transmitter including: a destination decoder to identify, for each packet in the input packet traffic, a respective destination target in the plurality of targets; a plurality of emitter modules operating at different wavelengths for converting the electrical signals into optical signals; and a de-multiplexer, which is controlled by the destination decoder and is able to drive the emitter modules by sending selectively to each emitter module the electrical signals corresponding to a given packet of the input packet traffic according to the respective destination target identified by the destination decoder. A serialization module is set upstream of the de-multiplexer for converting the packet traffic into a serial flow of bits.

Abstract: An optical pulse generating device includes a continuous light input unit to which continuous light is input; a pulse input unit to which control pulse light that includes periodic pulses of light is input; and a generating unit that generates pulse light from the continuous light by clipping the continuous light according to a variation of emission intensity of the control pulse light.

Abstract: A system includes an optical line terminal (OLT) that includes an OLT transmitter. The OLT transmitter includes one or more fixed wavelength optical sources that generate an optical signal at a first wavelength, and an optical waveguide that transmits the optical signal at the first wavelength in an optical network.

Abstract: An optical transceiver comprising: an optical transmitter having plurality of light sources controllable to generate optical signals in different optical channels, an output aperture, an optical multiplexer that multiplexes optical signals generated by the light sources and transmits them to exit the transceiver from the output aperture; an optical receiver having a plurality of optical sensors, an input aperture for receiving optical signals in a plurality of optical channels, a demultiplexer that demultiplexes signals received at the input aperture, and directs signals received in different channels to different optical sensors of the plurality of optical sensors; and a QSFP compliant housing that houses the transmitter and receiver.

Abstract: A wavelength-selectable laser device generally includes an array of laser emitters and a filtered external cavity for filtering light emitted from the laser emitters and reflecting different wavelengths back to each of the laser emitters such that lasing occurs at different wavelengths for each of the laser emitters. Each laser emitter includes a gain region that emits light across a plurality of wavelengths including, for example, channel wavelengths in an optical communication system. The filtered external cavity may include a dispersive optical element that receives the light from each of the laser emitters at different angles and passes or reflects different wavelengths of the light at different angles such that only wavelengths associated with the respective laser emitters are reflected back to the respective laser emitters. By selectively emitting light from one or more of the laser emitters, one or more channel wavelengths may be selected for lasing and transmission.

Abstract: Consistent with the present disclosure, data, in digital form, is received by a transmit node of an optical communication system, and converted to an analog signal by a digital-to-analog converter (DAC) to drive a modulator. The modulator, in turn, modulates light at one of a plurality of wavelengths in accordance with the received data forming a plurality of corresponding carriers. The carriers are modulated according to one of a plurality of modulation formats and then optically combined to form a superchannel of a constant maximum capacity, for example. Accordingly, the number of carriers and the bit rate for each carrier remain constant for each modulation format to realize a constant maximum capacity. The superchannel is then transmitted over an optical communication path to a receive node. At the receive node, the superchannel is optically demultiplexed from a plurality of other superchannels.

Abstract: Consistent with the present disclosure, data, in digital form, is received by a transmit node of an optical communication, and converted to analog signal by a digital-to-analog converter (DAC) to drive a modulator. The modulator, in turn, modulates light at one of a plurality of wavelengths in accordance with the received data forming a plurality of corresponding carriers. The plurality of carriers are then optically combined with a fixed spacing combiner to form a superchannel of a fixed capacity. Accordingly, the number of carriers are selected according to a modulation format and symbol rate to realize the fixed capacity, for example. The superchannel is then transmitted over an optical communication path to a receive node. At the receive node, the superchannel is optically demultiplexed from a plurality of other superchannels.

Abstract: Consistent with the present disclosure, data, in digital form, is received by a transmit node of an optical communication system, is processed and then output to drive a modulator. The modulator, in turn, modulates light at one of a plurality of wavelengths in accordance with the received data, forming a plurality of corresponding carriers. The plurality of wavelengths used for the plurality of carriers are spectrally spaced apart by a common, periodic fixed spacing. The plurality of carriers are optically combined with a fixed spacing combiner to form a superchannel. A plurality of superchannels are generated and then multiplexed together onto an optical communication path and transmitted to a receive node. Each superchannel includes a plurality of carriers, each spectrally separated by the same fixed spacing. The plurality of superchannels are spectrally separated by an amount corresponding to the fixed spacing of the plurality of carriers.

Abstract: A signal transmitting device includes a transmitter, a receiver, and four optical fibers. The transmitter includes a first electro-optical converter electro-optically converting original electrical red video signal into optical red video signal in original video signal, a second electro-optical converter electro-optically converting original electrical green video signal into optical green video signal a third electro-optical converter electro-optically converting original electrical blue video signal into optical blue video signal, a parallel/serial converter converting original electrical parallel signal having a lower transfer rate than a transfer rate of the original video signal into original electrical serial signal, and a fourth electro-optical converter electro-optically converting the original electrical serial signal transmitted from the parallel/serial converter into optical serial signal.

Abstract: A system for enabling reconfiguration of a Wavelength Division Multiplexed (WDM) optical communications network. A plurality of channel transmitters are provided for generating respective optical signals within corresponding wavelength channels of the network. A broadband light source generates a broadband continuous wave light having a bandwidth corresponding to a channel band of the network. A wavelength selective switch includes a first switch port connected to receive optical signals from the channel transmitters. A second switch port is connected to receive the broadband continuous wave light from the broadband light source. The wavelength selective switch is configured to comb the broadband continuous wave light into a plurality of narrowband lights respectively corresponding with wavelength channels of the network. A common-OUT port of the wavelength selective switch outputs a WDM signal for transmission through a downstream fiber span of the network.

Abstract: An optical communication system includes logic to communicate using optical channels set outside a fiber zero dispersion zone, and having channel spacing that decreases with increasing distance from the fiber zero dispersion zone.

Abstract: The present invention discloses a transmission device of a low-noise optical signal having a low-noise multi-wavelength light source, a transmission device of broadcast signals using a low-noise multi-wavelength light source, and an optical access network having the same. The present invention uses a low-noise multi-wavelength light source (LMLS) which has sufficiently low noises at respective wavelengths, while being lasing at a multi-wavelength. Noises at respective wavelengths are not increased, even though an output light of such an LMLS passes through a wavelength division multiplexer/demultiplexer (a tunable optical filter or an arrayed waveguide grating (AWG), etc.). When using an LMLS, it is possible to embody an optical access network capable of transmitting optical signals at a high-speed and simultaneously transmitting a multicast signal. Further, when embodying an optical amplifier by using a gain medium for an LMLS, it is possible to obtain gain at a broad band without cross-coupling.

Abstract: Consistent with the present disclosure, an optical receiver is paired with an optical transmitter in a transceiver card or module, for example. During normal operation, the optical transmitter supplies optical signals for downstream transmission on a first optical communication path, and the optical receiver receives additional optical signals from a second optical communication path. During a transmitter monitoring mode (or “loopback”), however, when monitoring of transmitter parameters is desired, an optical switch directs the output or portion thereof from the transmitter to the receiver. The receiver may then supply monitoring data or information to a control or processor circuit, which, in turn, may supply control signals to the transmitter. In response to such control signals, the performance of the transmitter may be optimized, for example, by reducing BER and/or OSNR to a desired level.

Abstract: Coded light has been proposed to enable advanced control of light sources and transmit information using light sources. An assignment for the identification frequencies of light sources enables more unique frequencies to be assigned, i.e. more light sources to be uniquely identified in the system. An available frequency band is divided into non-uniform frequency regions and frequencies are selected from a set of uniformly spaced frequencies in the non-uniform frequency regions. A receiver is based on a successive approach and is enabled to analyze higher harmonics of the received light signals. The light contributions are successively estimated group by group.

Abstract: An optical signal generator includes a splitter, a first modulator, a second modulator, a signal-switching unit and a multiplexer. The splitter splits an optical pulse train into a first pulse train and a second pulse train. The first modulator receives the first pulse train and first data signal, and generates a first modulation signal by performing on-off-keying or phase modulation on the first pulse train based on the strength of the first data signal. The second modulator receives the second pulse train and second data signal, and generates a second modulation signal by performing the on-off-keying or phase modulation on the second pulse train based on the strength of the second data signal. The signal-switching unit delays pulses of the second modulation signal or adjusts a phase of a carrier included in the second modulation signal according to a switching signal. The multiplexer generates an optical modulation signal by multiplexing the first modulation signal and the second modulation signal.

Abstract: An optical device that includes multiple optical modulators having actual operating wavelengths at a given temperature is described. Because of differences between the actual operating wavelengths and target operating wavelengths of the optical modulators, heating elements may be used to thermally tune the optical modulators so that the actual operating wavelengths match corresponding carrier wavelengths in a set of optical signals. Furthermore, control logic in the optical device may assign the optical modulators to the corresponding carrier wavelengths based at least on differences between the carrier wavelengths and the actual operating wavelengths, thereby reducing an average thermal tuning energy associated with the heating elements.

Abstract: An apparatus includes an array of lasers, an array of electrical drivers, and optical filter. Each laser is configured to produce light in a corresponding wavelength-channel, wherein the wavelength-channels of different ones of the lasers are different. The electrical drivers are connected to directly modulate the lasers. Each driver produces a first driving current or voltage to cause a corresponding one of the lasers to be in a first lasing state and produces a different second driving current or voltage to cause the corresponding one of the lasers to be in a different second lasing state. The optical filter is connected to receive light output by the lasers. The optical filter selectively attenuates light from each of the lasers in the first lasing states thereof and to selectively pass light from each of the lasers in second lasing states thereof.

Abstract: A transmissive active channel element is provided in each signal channel of a monolithic multi-channel TxPIC where each channel also includes a modulated source. The active channel element functions both as a power control element for both monitoring and regulating the output channel signal level of each signal channel and as a modulator for channel wavelength tagging or labeling to provide for wavelength locking the modulated sources. The power regulating function is also employed to control the channel signal power outputs of each channel to be uniform across the channel signal array. All of these functions are carried out by a feedback loop utilizing digital signal processing.

Abstract: Photonic integrated circuits (PICs) may include transmit and receive PICs that include individually tunable optical elements. In one implementation, a device may include a number of optical elements that form a number of optical channels. Tuners may be used to modify a property associated with the at least one of the optical elements where the modified properties of the optical elements adjust a frequency grid of the optical channels.

Abstract: When using a wavelength multiplexing unit of a wavelength multiplexing optical transmission system in which a wavelength tunable type optical transmitter and a wavelength multiplexer having no wavelength selectivity are combined, undesired light that is not supposed to be flown into a wavelength channel may be mixed therein. A wavelength multiplexing unit includes: transmitters having functions of outputting signal lights of different wavelengths from each other and changing the wavelengths; band-limiting filters provided to each of the transmitters, which have functions of eliminating the lights out of bands from the signal lights outputted from the transmitters, and changing the center wavelengths of the bands; and a wavelength multiplexer including ports capable of inputting the lights of any wavelengths, which inputs signal lights from which the light out of the bands is eliminated by the band-limiting filters and multiplexes the signal lights.

Abstract: The present invention relates to a wavelength-division multiplexed passive optical network (WDM-PON) which embodies wavelength-independence of wavelength-locked Fabry Perot-Laser Diode (F-P LD).

Abstract: The present invention relates to an optical modulation method and optical modulation system of a wavelength locked Fabry Perot-Laser Diode (FP-LD) by injecting a broadband light source (BLS) using mutual injection of FP-LDs. More specifically, the present invention relates to a novel modulation technology which embodies a wavelength locked FP-LD capable of being used as an economic light source in an optical network based on a wavelength-division multiplexing passive optical network (WDM-PON).

Abstract: A method for transmission of multiple, independent data packages across a single optical fiber utilizing both time division multiplexing and wavelength division multiplexing is described. The method includes transmitting a first data package across the single optical fiber at a first wavelength and transmitting a second data package across the same optical fiber at a second wavelength, in either the same direction or in a direction opposite as the first data package, wherein the second data package transmission may be concurrent with the first data package transmission. the method further includes separating the data package transmissions into two optical paths, filtering the second wavelength from a first of the two optical paths, detecting the first data package at the first wavelength, filtering the first wavelength from a second of the two optical paths, and detecting the second data package data at the second wavelength.

Abstract: A method of optical communication includes generating an amplified optical signal from at least a portion of a first optical signal having a first carrier wavelength, ?1. The amplified optical signal is applied to Brillouin media to stimulate generation of a Brillouin effect signal at a wavelength ?2. The Brillouin effect signal is modulated to produce a second optical signal having a second carrier wavelength, ?2. In one embodiment, the first optical signal is a downstream optical signal and the second optical signal is an upstream optical signal of a passive optical network.

Abstract: Low-cost FP lasers can be implemented in the upstream links of a WDM PON system by configuring them for single-mode operation. In a typical embodiment, an FP laser at a subscriber unit is injection seeded with CW seed light from a DFB laser or an ASE source at a central office to enable single-mode operation of the FP laser. The FP laser is directly modulated and the resulting optical data signal is transmitted upstream to the central office. At the central office, an optical spectrum reshaper/bandpass optical filter is positioned in front of an optical receiver to enhance the extinction ratio of the optical data signal and generate a vestigial sideband. A wavelength locker can also be implemented at the central office to stabilize the wavelength of the master DFB laser and the injection-seeded FP laser.

Abstract: A wavelength division multiplexing transmission system, the system comprising: a plurality of channels at different wavelengths, each channel comprising a transmitter, a receiver, and one or more amplifiers, the system further comprising an encoder for encoding data with a coding, and; a decoder for decoding transmitted data; prioritizing means for prioritizing the data on each channel; monitoring means for monitoring directly or indirectly, raw (uncorrected) bit errors on each channel; power adjusting means for, varying the power on a channel in response to the bit error rate.

Abstract: A method and apparatus is provided for tracking a thermally floating wavelength signal channel grid generated at an optical transmitter (Tx) in an optical transmission system or optical network where the wavelengths of the individual Tx signal channels may move in wavelength due to, for example, changes in ambient temperature at the optical transmitter but the channel spacing between Tx signal channels along the thermally floating Tx wavelength grid remains constant.

Abstract: An apparatus for use in an optical transceiver module that incorporates an integrated multiplexer/demultiplexer for high speed data transfer applications. One example embodiment includes a transmissive block arranged to interface with a transmit optical port, a receive optical port, and a plurality of optical subassemblies. The transmit optical port may transmit a first multiplexed optical signal and the receive optical port may receive a second multiplexed optical signal. Filters may be positioned between the transmissive block and one or more of the optical subassemblies to transmit signals at predetermined wavelengths while reflecting other signals incident thereon.

Abstract: An optical network unit (ONU) comprising a first optical fiber, a first optical circulator coupled to the first optical fiber, a first seed light injected laser coupled to the first optical circulator, wherein the first optical circulator is positioned between the first seed light injected laser and the first optical fiber, and a second seed light injected laser coupled to the first optical circulator and the first seed light injected laser, wherein the first optical circulator is positioned between the second seed light injected laser and the first optical fiber. Also disclosed is a method comprising receiving a seed light signal, amplifying the seed light signal using seed light injection locking, thereby producing an amplified seed light signal, and producing an optical signal using the amplified seed light signal and seed light injection locking, wherein the optical signal has about the same wavelength as the seed light signal.

Abstract: An inline repeater that uses a forward-pumped DRA that can use a pumping light source such as an FBG pumping light source and a fiber laser, which are the most commonly used, and an optical fiber communication system are realized.