39results about "Optical transmission" patented technology

A receiver of an optical communication system includes an organic photoelectric conversion device configured to convert optical signals received from a transmitter into an electrical signal; and a demodulator configured to input the electrical signal to a trained artificial neural network and demodulate the electrical signal based on an output of the trained artificial neural network.

This application relates to the field of optical communication technologies, and in particular, to an optical module, an optical communication device, and an optical communication system. Costs can be reduced, functions can be added, and an occupied volume can be reduced based on a service function and at least one operation and maintenance function. The optical module may include a control unit, a laser service driving circuit, an optical transmitting unit, and a first optical receiving unit. The control unit determines a target mode of the optical module from a plurality of working modes, and controls to output a target signal corresponding to the target mode to the laser service driving circuit. The plurality of working modes include at least one of an OTDR mode and a service mode. The laser service driving circuit outputs a laser signal to the optical transmitting unit based on the target signal. When the target mode is the OTDR mode, the first optical receiving unit receives and transmits, to the control unit, a second OTDR signal returned in an optical fiber. A first OTDR signal and the second OTDR signal are used to perform optical signal transmission analysis.

An optical transmission system includes a first optical transmission device that transmits an OSC (Optical Supervisory Channel) light to an optical transmission line, and a second optical transmission device that receives for receiving the OSC light from the optical transmission line. The first optical transmission device includes a first controller that detects a transmission line disconnection before communication with the OSC light is established in the optical transmission line, based on a first detection method, and a second optical transmission device including a second controller that detects a transmission line disconnection after the communication with the OSC light is established in the optical transmission line, based on a second detection method different from the first detection method.

A method for reconstructing a first information stream and a second information stream, the method includes receiving, by an optical receiver, a received multiplexed optical signal that is a transmitted optical signal that passed through a polarization and phase rotating medium, the transmitted multiplexed optical signal being generated by using at least one transmitter phase-modulated periodical pilot signal, and by allocating a first polarization to the first information stream and a second polarization that differs from the first polarization to the second information stream; and processing the received multiplexed optical signal to provide a first reconstructed information stream and a second reconstructed information stream, wherein the processing comprises using at least one receiver phase-modulated periodical pilot signal that is associated with the at least one transmitter phase-modulated periodical pilot signal.

Adjustment of one of more control parameters of a section (10) of an optical fiber network is accomplished by applying one or more control algorithms using estimated data. The estimated data are derived (4) from measurements (2) of optical signals in the section and from knowledge of the section. The estimated data is a function of optical nonlinearity and of amplified spontaneous emission. Alternately, multiple receivers (64) are comprised in a flexible coherent transceiver (54) of a multi-span optical fiber network, each receiver operative to handle communications on a respective channel. The multiple receivers measure optical characteristics. For each receiver, the optical characteristics include optical nonlinear interactions on the respective channel, the optical nonlinear interactions being at least partially dependent from one span (56) to another span (56). An optical power of a signal on each of the multiple channels is adjusted as a function of the optical characteristics.

A slave station device including: a superposition unit that is capable of superposing a main signal and a master station control signal by an electrical domain superposition method in which the main signal and the master station control signal for controlling a master station device connected to the slave station device are converted into an optical signal after multiplexing and an optical domain superposition method in which the main signal is modulated into an optical signal and then optically modulated by the master station control signal, and superposes the main signal and the master station control signal by any one of the electrical domain superposition method and the optical domain superposition method; and a control unit that controls the superposition method by the superposition unit on the basis of a slave station control signal indicating the superposition method received from the master station device.

A transmission apparatus causes a digital-to-analog conversion unit to perform digital-to-analog conversion on transmission signals pre-equalized by using a compensation filter, then converts electrical signals into optical signals, and outputs the optical signals. A receiving apparatus converts the received optical signals into received electrical signals, then performs analog-to-digital conversion, and demodulates the received signals. A scale estimation unit calculates a slope near an amplitude 0 in a correlation between an amplitude distribution of the pre-equalized transmission signals and an amplitude distribution of the received signals. A scale unit scales amplitude of the received signals on the basis of the calculated slope. A coefficient estimation unit calculates a filter coefficient of the compensation filter on the basis of the pre-equalized transmission signals and the scaled received signals. An output amplitude level determination unit determines output levels of the transmission signals from the digital-to-analog conversion unit on the basis of a correlation between distributions of amplitudes of non-pre-equalized and pre-equalized transmission signals.

In one embodiment, an apparatus is configured to perform obtaining a received signal from a plurality of Optical Network Units, ONUs connected to the OLT, wherein the received signal includes at least a desired signal originating from a first ONU; determining a magnitude of the desired signal based on the received signal; adjusting an equalizer based on the magnitude of the desired signal; equalizing the received signal using the equalizer such that an equalized signal corresponding to an estimate of desired signal is obtained; and providing the equalized signal for further processing.

The invention is applied to an optical network of the type comprising an optical transmitter [110, Fig. 1], such as an optical line termination (OLT), connected by a first optical fibre to an optical

The embodiment of the application discloses a kind of optical signal sending method, pilot receiver and transmitter, belong to optical communication technical field.The method comprises the following steps: modulating first pilot signal on the first polarization state of optical signal;Modulate the second pilot signal on the second polarization state of optical signal;Wherein, the phase of first pilot signal and the phase of second pilot signal are different;Output modulated optical signal;Using the application, the interference of pilot signal transferred to other wavelength optical signal in the above Raman power transfer effect can be weakened.

An optical transmission device includes a light output unit that outputs OSC (Optical Supervisory Channel) light, a calculator that calculates a tilt amount of a tilt occurring in a pseudo light in an optical transmission line connecting the optical transmission device and another optical transmission device facing the optical transmission device when establishing communication between the optical transmission device and the another optical transmission device based on the OSC light and the pseudo light including a wavelength band of a signal light repeated by the optical transmission device, and a controller that controls output of the pseudo light based on the tilt amount.

An optical transmission system includes a first optical transmission device and a second optical transmission device facing each other via an optical transmission line. The first optical transmission device includes a first optical outputter that outputs first OSC light, a first pseudo light source that outputs first pseudo light including a wavelength band of first signal light, and a first transmitter that transmits first multiplexed light obtained by multiplexing the first OSC light and the first pseudo light toward the second optical transmission device. The second optical transmission device includes a second optical outputter that outputs second OSC light, a second pseudo light source that outputs second pseudo light including a wavelength band of second signal light, and a second transmitter that transmits second multiplexed light obtained by multiplexing the second OSC light and the second pseudo light toward the first optical transmission device.

The present application provides a driver amplifier circuit. The driver amplifier circuit includes a nonlinear differential amplifier and a nonlinear resistor connected across the output terminals of the differential amplifier. The nonlinear resistor has a resistance value that increases as the magnitude of the differential voltage across the nonlinear resistor increases. A transmitter may include the driver amplifier.

The optical transmission system (10) of the present invention includes N directly modulated lasers that convert N-channel first electrically modulated signals into N-channel optically modulated signals and transmit them, N photodetectors that receive the N-channel optically modulated signals and convert them into N-channel second electrically modulated output signals, and at least one of a first MIMO equalizer (108) that performs an equalization process on the N-channel first electrically modulated signals to compensate for crosstalk between the N-channel first electrically modulated signals, and a second MIMO equalizer (108) that performs an equalization process on the N-channel second electrically modulated signals to compensate for crosstalk between the N-channel second electrically modulated signals, and uses matrix coefficients based on an impulse response for the equalization process. As a result, the present invention can provide an optical transmission system capable of reducing crosstalk and achieving good BER characteristics.

Techniques are described for providing a hybrid compensation of chromatic dispersion in optical networks to reduce power consumption by coherent receivers. In some examples, a controller may receive a chromatic dispersion value of an optical signal from a coherent receiver integrated with a receiver optical network device. The controller may compare the chromatic dispersion value with a threshold. The controller may, in response to determining that the chromatic dispersion value satisfies the threshold, perform at least one of: configure a switch connected to a dispersion compensation module (DCM) with a state to provide access to the DCM to compensate the chromatic dispersion value of the optical signal, or adjust a phase response of a filter of a coherent transmitter to compensate the chromatic dispersion value of the optical signal.

An optical transmitter includes: a modulation signal generator that generates a modulation signal that is a digital signal in which a first pilot symbol signal having a first symbol period and a second pilot symbol signal having a second symbol period are inserted into data to be transmitted; and an optical modulator that generates modulated light by modulating CW light from a CW light generator, and an optical receiver includes: an optical coherent detector that receives polarization-multiplexed modulated light into which the first pilot symbol signal and the second pilot symbol signal are inserted, coherently detects the received modulated light; and a reception-side digital signal processor including a frequency difference compensator that calculates a phase difference using the first pilot symbol signal and the second pilot symbol signal adjacent to the first pilot symbol signal, and compensates a frequency of the received digital signal.

The objective is to provide an optical transmission system and optical transmission device that improves the intensity of OSC (Optical Supervisory Channel) light. [Solution] The optical transmission system includes a first optical transmission device and a second optical transmission device facing each other via an optical transmission path, wherein the first optical transmission device has a first optical output unit that outputs first OSC light, a first pseudo-light source that outputs first pseudo-light including the wavelength band of first signal light, and a first transmitting unit that transmits first combined light obtained by combining the first OSC light and the first pseudo-light toward the second optical transmission device, and the second optical transmission device has a second optical output unit that outputs second OSC light, a second pseudo-light source that outputs second pseudo-light including the wavelength band of second signal light, and a second transmitting unit that transmits second combined light obtained by combining the second OSC light and the second pseudo-light toward the first optical transmission device.

A method (400) for overlapping spectrum amplification includes receiving an optical signal (102) and splitting the optical signal into a first split signal (102a) having a first wavelength band (λa) and a second split signal (102b) having a second wavelength band (λb). The splitting results in a band gap (G) between the first wavelength band and the second wavelength band. The method further includes delaying the first split signal by a threshold period of time relative to the second split signal and combining the first split signal and the second split signal, resulting in a combined signal (104) having the first wavelength band and the second wavelength band without the band gap therebetween. The path difference between the first split signal along the first signal path (P1) and the second split signal along the second signal path (P2) is within a threshold multipath interference compensation range.

Aspects of the disclosure provide a device and method of adjusting received signals to correct for errors resulting from mode mixing in a multimode fiber (20,410,510) using an optical phased array (OPA) photonic integrated circuit (PIC) (112, 132, 500a, 500b) based device. The method including receiving, at an OPA PIC (112, 132, 500a, 500b), a first signal from the multimode fiber (20,410.510); receiving, at the OPA PIC (112, 132, 500a, 500b), a plurality of control wavelengths, wherein each of the plurality of control wavelengths is encoded with a distinct spatial mode and wherein the first signal and the plurality of control wavelengths are co-propagating signals; determining, by one or more processors (512,512b) of the OPA PIC (112, 132, 500a, 500b), a cross-coupling matrix based on the control wavelengths, the cross-coupling matrix being indicative of errors in the first signal; and adjusting, by the one or more processors (512,512a, 512b) of the OPA PIC (112, 132, 500a, 500b), the first signal based on the cross-coupling matrix.

A transmission apparatus causes a digital-to-analog conversion unit to perform digital-to-analog conversion on transmission signals pre-equalized by using a compensation filter, then converts electrical signals into optical signals, and outputs the optical signals. A receiving apparatus converts the received optical signals into received electrical signals, then performs analog-to-digital conversion, and demodulates the received signals. A scale estimation unit calculates a slope near an amplitude 0 in a correlation between an amplitude distribution of the pre-equalized transmission signals and an amplitude distribution of the received signals. A scale unit scales amplitude of the received signals on the basis of the calculated slope. A coefficient estimation unit calculates a filter coefficient of the compensation filter on the basis of the pre-equalized transmission signals and the scaled received signals. An output amplitude level determination unit determines output levels of the transmission signals from the digital-to-analog conversion unit on the basis of a correlation between distributions of amplitudes of non-pre-equalized and pre-equalized transmission signals.

The objective is to provide an optical transmission device and optical transmission system that reduces the tilt amount of pseudo-light. [Solution] The optical transmission device is an optical transmission device that relays signal light and includes an optical output unit that outputs OSC (Optical Supervisory Channel) light, a calculation unit that calculates the amount of tilt generated in the pseudo-light in the optical transmission path connecting the optical transmission device and the other optical transmission device when establishing communication between the optical transmission device and the other optical transmission device based on the OSC light and pseudo-light including the wavelength band of the signal light, and a control unit that controls the output of the pseudo-light based on the amount of tilt.

A coherent optical reception device includes a coherent receiver that receives signal light in which an AMCC signal is superimposed on a main signal, converts the signal light into an analog electric signal, and outputs an in-phase component and a quadrature-phase component of a reception signal for each polarization state, and a polarization combiner that performs polarization combining on the in-phase component and the quadrature-phase component of the reception signal output from the coherent receiver for each polarization state and outputs the reception signal as an AMCC signal identification reception signal that is the reception signal used for identification of the AMCC signal and a main signal identification reception signal that is the reception signal used for identification of the main signal.

In some embodiments, an apparatus includes a first optical transceiver. The first optical transceiver includes a set of optical transmitters, an optical multiplexer operatively coupled to the set of optical transmitters, and a variable optical attenuator operatively coupled to the optical multiplexer. The variable optical attenuator is configured to receive a control signal from a controller of the first optical transceiver and modulate a signal representing control information with an output from the optical multiplexer. The control information is associated with the control signal and for a second optical transceiver operatively coupled to the first optical transceiver.

Techniques are described for implementing an out-of-band communication channel used to exchange control channel information in sub-carrier-based optical communication systems. In an example implementation, a transmitter includes a laser operable to supply an optical signal, a digital signal processor operable to supply first electrical signals based on first data input to the digital signal processor and second data input to the digital signal processor, digital-to-analog conversion circuitry operable to output second electrical signals based on the first electrical signals, modulator driver circuitry is operable to output third electrical signals based on the second electrical signals, and an optical modulator operable to supply first and second modulated optical signals based on the third electrical signals. The first modulated optical signal includes a plurality of optical subcarriers carrying user data. The second modulated optical signal is polarization modulated based on the second data.

An optical transmitter (100) is provided with: a modulation signal generation unit (110) that generates a modulation signal that is a digital signal in which a first pilot symbol signal comprising a first symbol period and a second pilot symbol signal comprising a second symbol period are inserted into the data to be transmitted; and an optical modulation unit (130) that modulates CW light from a CW light generation unit (140) on the basis of the modulation signal converted to an analog signal by a digital / analog conversion unit (120) to generate modulated light into which the first pilot symbol signal and the second pilot symbol signal are inserted. An optical receiver (200) is provided with: a coherent detection unit (210) that receives polarization-multiplexed modulated light into which the first pilot symbol signal comprising the first symbol period and the second pilot symbol signal comprising the second symbol period are inserted, and outputs an analog electrical signal by coherent detection of the received modulated light; and a reception-side digital signal processing unit (240) having a frequency difference compensation unit (247) that calculates a phase difference using the first pilot symbol signal inserted into the received polarization-multiplexed modulated light and the second pilot symbol signal adjacent to the first pilot symbol signal having been extracted from the digital signal from an analog / digital converter unit (230), and compensates for the frequency of the received digital signal.

An optical signal transmission device and method based on digital predistortion in a symbol domain is provided. The optical signal transmission device includes: a memory; and a processor coupled to the memory to control execution of a process to: perform digital predistortion processing on a symbol sequence of a signal to be transmitted to obtain a digital predistortion processed signal; perform short-pulse shaping processing on the digital predistortion processed signal to obtain a short-pulse shaping processed signal, wherein a memory length introduced by the short-pulse shaping processing is less than or equal to a memory length of the optical transmitter; and generate and transmit an optical signal based on the short-pulse shaping processed signal.

Systems and methods are provided for implementing a hollow core fiber-based line-system with an out-of-band optical supervisory channel. A first transponder, located at a first location, transmits optical data traffic at a first wavelength range to a second transponder, at a second location, over at least one hollow core fiber ("HCF") cable communicatively coupling the first and second transponders over a fiber path distance that is at least 60 kilometers. The first transponder further transmits an optical supervisory channel ("OSC") signal at a second wavelength to the second transponder over the at least one HCF cable. The OSC signal corresponds to diagnostic data associated with transmission of the optical data signal and / or associated with operation of a system including the first and second transponders. The second wavelength is separate from the first wavelength range by at least a threshold wavelength separation.

The disclosed system and method are designed for monitoring optical performance, comprising: receiving an optical channel signal, wherein the optical channel signal is superimposed with a tuning point (PT) signal; operating a local oscillator (LO) including a tunable laser in a coarse scan mode and a fine scan mode, and generating different LO signals depending on the mode in which the LO is operating; merging the optical channel signal with at least one LO signal generated by the LO to generate a merged optical signal; detecting the merged optical signal and converting the merged optical signal into an electrical signal; amplifying the electrical signal; converting the amplified electrical signal into a digital signal; processing the digital signal and extracting channel-specific information included in the PT signal; calculating channel power based on the channel-specific information; and maintaining a management table.

Proposed is a technology for compensating for the performance of a transmitter using a pre-distortion method in an optical communication system, wherein a signal sending apparatus may include a transceiver, and at least one controller operably connected to the transceiver, wherein the at least one controller is configured to receive a digital signal, to modulate the digital signal into a PAM signal, to provide the PAM signal to a signal receiving apparatus, to obtain a distortion coefficient value from the signal receiving apparatus, to perform a nonlinear pre-distortion on PAM signals on the basis of the distortion coefficient value, and to provide a result signal generated on the basis of the nonlinear pre-distortion to the signal receiving apparatus.

The objective is to provide optical transmission systems and devices that improve safety before optical communication via OSC (Optical Supervisory Channel). [Solution] The optical transmission system includes a first optical transmission device that transmits OSC light to an optical transmission path and a second optical transmission device that receives the OSC light from the optical transmission path, wherein the first optical transmission device has a first control unit that detects a transmission path interruption before the OSC light is transmitted in the optical transmission path based on a first detection method, and the second optical transmission device has a second control unit that detects a transmission path interruption after the OSC light is transmitted in the optical transmission path based on a second detection method different from the first detection method.