Abstract: A method, an optical node, and an optical network include a power controller configured to bring channels in-service in parallel over multiple cascaded optical nodes quickly, efficiently, and in a non-service affecting manner. The method, node, and network utilize multiple states of a control loop that maintains a stable response in downstream optical nodes as channels are added in parallel. Further, the power controller is configured to operate independently alleviating dependencies on other power controllers and removing the need for coordination between power controllers. The method, node, and network provide efficient turn up of dense wave division multiplexing (DWDM) services which is critical to optical layer functionality including optical layer restoration.

Abstract: An optical transmission device that receives a wavelength division multiplexed optical signal obtained by dividing an optical packet signal and performing wavelength multiplexing and that transmits via an optical switch the received wavelength division multiplexed optical signal includes an optical power level measurement unit configured to measure respective optical power levels of respective optical signals of wavelengths included in the wavelength division multiplexed optical signal, and a routing information determinator configured to determine routing information of the wavelength division multiplexed optical signal on the basis of the measured optical power levels.

Abstract: An optical access network comprises optical network units connected to a node. A monitoring unit determines information indicative of energy consumption at the optical network unit over a period of time. An optical network unit can operate in operating states/modes which differ in their energy consumption. Monitoring unit can determine the information by determining a time that an optical network unit spends in the different operating states/modes. Monitoring unit can use a state machine at the node which represents the optical network unit. An optical network unit can locally record time spent in states/modes and forward this to the monitoring unit. An optical network unit can locally monitor energy consumption and forward this to the monitoring unit. An operational parameters of the access network can be modified based on the information determined by the monitoring unit.

Abstract: An optical line terminal (OLT) includes an optical receiving assembly and a processor (4). A current mirror (1), a current-voltage conversion circuit (2) and a switching circuit (3) are connected in sequence between the optical receiving assembly and the processor (4). An energy storage circuit connected to ground is connected between the switching circuit (3) and the processor (4). The optical receiving assembly generates a response current according to the optical signal received. The current mirror (1) processes the current and then transmits it to the current-voltage conversion circuit (2). The conversion circuit (2) converts the current into a voltage signal and transmits the voltage signal to the switching circuit (3). The switching circuit (3) transmits the voltage signal outputted by the conversion circuit (2) to the energy storage circuit. The voltage signal is sampled and held by the energy storage circuit and then outputted to the processor (4).

Abstract: An optical packet switching apparatus includes (i) an optical packet switch for switching the route of an inputted optical packet signal and outputting the inputted optical packet signal, (ii) an input-side packet density monitoring unit for detecting the packet density of optical packet signals inputted to the optical packet switch, (iii) a first input-side optical amplifier provided on an input side of the optical packet switch, (iv) a first input-side variable optical attenuator (VOA) provided posterior to the optical amplifier, (v) a storage for storing the gain characteristics in relation to the packet density at the first input-side optical amplifier, and (vi) an input-side VOA control unit for controlling the attenuation by the first input-side VOA in such a manner as to compensate for the gain fluctuations due to the variations in the packet density at the first input-side optical amplifier, based on the packet density and the gain characteristics.

Abstract: A detection system for monitoring the intensity of a stream of modulated pulses, the system comprising a controller configured to provide a control signal to a component outputting modulated pulses the control signal controlling the level of modulation for each pulse exiting the component and a detector configured to measure the intensity of the pulses in the stream of pulses exiting the component outputting modulated pulses, wherein the detector comprises a gated detector, the controller being configured to send a gating signal to said detector, wherein said gating signal varies the gain of the detector with the control signal, such that pulses with a selected modulation level can be detected.

Abstract: A detection device is electrically connected to a controlled device through a power line and configured for detecting a power condition of the controlled device. The detection device at least includes a power detection module, a processing unit, and an infrared transmitter. The power detection module is configured for detecting an input current transmitted through the power line from the controlled device and converting the input current to an output voltage signal. The processing unit is configured for receiving the output voltage signal and determining the power condition of the controlled device based on a voltage level of the output voltage signal. The infrared transmitter is configured for transmitting an infrared signal based on the determined result of the processing unit to switch the controlled device such that the controlled device performs a corresponding operation. Further, a detecting method is also disclosed.

Abstract: A wavelength division multiplexer terminal with a multiplexer arrangement with a first switching matrix, and a demultiplexer arrangement with a second switching matrix allows flexibility for connection transceivers to ports of the wavelength division multiplexer and wavelength division demultiplexer respectively. Optical monitoring receivers are connected upstream the wavelength division multiplexer and downstream the wavelength division demultiplexer for managing and supervising connections.

Abstract: There are disclosed techniques for power control in an Optical Network Unit (ONU) of a Passive Optical Network (PON). In one embodiment, the supply of power to an optical transmitter is controlled in accordance with information defining a plurality of transmission windows during which data can be transmitted from the ONU, in order to achieve the following: (1) to provide power to the optical transmitter beginning at a predetermined time in advance of a transmission window to ensure a laser in the optical transmitter is ready to begin transmitting the data at the start of the transmission window; and (2) to refrain from providing full power to the optical transmitter between transmission windows when the duration of time between the transmission windows is greater than a predetermined length.

Abstract: A self-characterization optical receiver comprising a tunable filter comprising a first transmission peak and configured to receive an optical signal comprising a plurality of channels at different wavelengths and output one channel at a wavelength corresponding to the first transmission peak, an optical-to-electrical (OE) converter configured to convert the one channel optical signal into an electrical signal, a monitor unit configured to adjust at least one control parameter based upon a power level of the electrical signal, and a control unit configured to adjust a heater bias current based upon control parameters received from the monitor unit, and wherein adjusting the heater bias current shifts the wavelength corresponding to the first transmission peak.

Abstract: In one example, an optical channel monitor includes a tunable filter, a deinterleaver, first and second optical receivers, and a control module. The tunable filter is configured to receive an optical signal having a plurality of channels spaced at a nominal channel spacing. The deinterleaver has an input with an input channel spacing Fi, an even output, and an odd output, the input being connected to an output of the tunable filter. The nominal channel spacing is between about one and two times the input channel spacing Fi. A ?20 dB bandwidth of the tunable filter is between about two and four times the input channel spacing Fi. The first and second optical receivers are coupled to the deinterleaver even and odd outputs, respectively. The control module is coupled to the tunable filter and is configured to tune the tunable filter to a desired center frequency.

Abstract: In one example, an optical channel monitor includes a tunable filter, a deinterleaver, first and second optical receivers, and a control module. The tunable filter is configured to receive an optical signal having a plurality of channels spaced at a nominal channel spacing. The deinterleaver has an input with an input channel spacing Fi, an even output, and an odd output, the input being connected to an output of the tunable filter. The nominal channel spacing is between about one and two times the input channel spacing Fi. A ?20 dB bandwidth of the tunable filter is between about two and four times the input channel spacing Fi. The first and second optical receivers are coupled to the deinterleaver even and odd outputs, respectively. The control module is coupled to the tunable filter and is configured to tune the tunable filter to a desired center frequency.

Abstract: Two or more optical transceivers coupled to each other by an optical link to optimize communication over the optical link. A first transceiver generates electrical data that represents an operational parameter for optimization. The transceiver then converts the electrical data into an optical signal and transmits the optical signal over the optical link to a second transceiver. The second transceiver recovers the electrical data from the optical signal and uses the recovered electrical data to change characteristics of the optical signal transmitted by the second transceiver.

Abstract: An optical coupling system is provided that includes a unitary, or integrally-formed, optical body having lenses formed on its lower end and a diffractive grating formed on its upper end. The unitary optical body is made of a material that is transparent to an operating wavelength of light. Some of the lenses are collimating lenses and some of the lenses are focusing lenses. Diverging light beams emitted by respective laser diodes of a parallel optical transmitter module are incident on the respective collimating lenses, which collimate the respective diverging light beams to produce respective collimated light beams. The respective collimated light beams are then incident on the diffractive grating. The diffractive grating divides each collimated beam into at least a first beam that is transmitted through the grating and a second beam that is reflected by the grating onto the monitor photodiode.

Abstract: An optical receiver includes a converter configured to convert, into an electrical signal, an optical signal including error correction information, the optical signal being received from a transmitting side; a corrector configured to correct an error on the electrical signal, based on the error correction information; a threshold controller configured to control a threshold value discriminating a power of the electrical signal, based on a result of the error correction; a table configured to form therein data of a relationship between the threshold value and a power of an optical noise occurring when the optical signal is amplified within an optical transmission path; and a deriving unit configured to obtain the power of the optical noise corresponding to the threshold value from the table.

Abstract: Electronic devices are provided that communicate over cables and other communications paths that include optical and electrical paths. A cable may include wires for forming an electrical path and one or more optical fibers for forming an optical path. Connectors at one or both ends of the cable may include electrical contacts and an optical coupling structure associated with the optical path. Optical paths may be included in connectors such as tip-ring-sleeve connectors and connectors of other types. Interface circuitry may be included in a connector to convert between optical and electrical signaling schemes. Wavelength-division-multiplexing may be used to support bidirectional communications. Breakout boxes and other equipment may be connected using the cables. Digital signals such as digital noise cancellation signals may be conveyed over the optical paths. Power and other electrical signals may be conveyed over the electrical paths.

Abstract: In one example embodiment, an optoelectronic communications assembly having an optical receiver or an optical transmitter includes an optical interface disposed at an end thereof and through which optical signals are communicated by the optical receiver or optical transmitter. The optoelectronic communications assembly also includes an electronic component and a first electrical interface disposed at the optical interface end of the optical communications assembly and communicatively coupled to the electronic component.

Abstract: A method of analysing an input signal, the method including the steps of: (a) dividing a first input signal into first and second orthogonal signal polarisation components; (b) dividing a second input signal into orthogonal first and second orthogonal local polarisation components; (c) mixing the first orthogonal signal component with the second orthogonal local polarisation component to provide a first mixed signal; (d) mixing the second orthogonal signal component with the first orthogonal local polarisation component to provide a second mixed signal; (e) analysing the first and second mixed signal to determine the polarisation or phase information in the input signal.

Abstract: A fiber optic network reduces distortion present in modulated optical signals received at an optical receiver from an optical transmitter via a fiber optic link. The optical receiver analyzes a received modulated optical signal, where the wavelength of the received signal is periodically varied at the transmitter around a center wavelength over a wavelength range. Based on the analysis, the receiver generates a link transmission curve indicative of the optical power of the received signal over the wavelength range. The network disclosed herein subsequently uses the link transmission curve to reduce the distortion caused by misalignment between the operating wavelength of a transmitter laser and a peak power wavelength at the peak power of the link transmission curve. For example, the transmitter may adjust the laser operating wavelength based on a control signal received from the receiver and generated at the receiver based on the link transmission curve.

Abstract: The present invention discloses a method and a device for detecting a signal power, and belongs to the field of communications. The method includes: when a receiver converts a received receive signal and outputs an output signal, separating a direct current signal and an alternating current signal from the output signal; converting the direct current signal into a first analog voltage signal; converting the alternating current signal into a second analog voltage signal through a transimpedance amplifier TIA; and obtaining a power of the receive signal according to the first analog voltage signal and the second analog voltage signal. The device includes: a first separating module, a first converting module, and an obtaining module. The present invention can improve accuracy of detecting a signal power.

Abstract: A method and a device for an optical power budget in a passive optical network are disclosed in the present invention, wherein said method includes: acquiring a corresponding minimum optical link loss according to a transmission requirement of a passive optical network with a large splitting ratio or long distance (710); selecting an optical transmitter with large power and an optical receiver with high sensitivity as a combination of an optical transmitter of an Optical Line Terminal (OLT) and an optical receiver of an Optical Network Unit (ONU) in an optical link, as well as a combination of an optical receiver of the OLT and an optical transmitter of the ONU in the optical link according to the minimum optical link loss to compose a passive optical network system comprising the OLT, an Optical Distribution Network (ODN), and ONUs connected in sequence (720).

Abstract: The present invention discloses an optical power monitoring method and apparatus.

Abstract: A method of operating a BPSK modulator includes receiving an RF signal at the BPSK modulator and splitting the RF signal into a first portion and a second portion that is inverted with respect to the first portion. The method also includes receiving the first portion at a first arm of the BPSK modulator, receiving the second portion at a second arm of the BPSK modulator, applying a first tone to the first arm of the BPSK modulator, and applying a second tone to the second arm of the BPSK modulator. The method further includes measuring a power associated with an output of the BPSK modulator and adjusting a phase applied to at least one of the first arm of the BPSK modulator or the second arm of the BPSK modulator in response to the measured power.

Abstract: An optical-source monitor images and diffracts received optical signals using an optical device that has a reflective geometry. For example, the optical device may include a diffraction grating on a curved surface, such as an echelle grating. By imaging and diffracting the optical signals, the optical device may couple to the optical signals on different diffraction orders of the optical device (which have different carrier wavelengths) from input optical waveguides to corresponding output optical waveguides. Then, output power monitors may measure the output power levels of the optical signals, and control logic may provide wavelength control signals to optical sources that provide the optical signals based on measured output power levels.

Abstract: A tracking system includes a tracking arrangement including a processor, memory, and at least a first interface port; and one or more optical modules. Each optical module includes a housing having at least one input port, at least a first output port, and at least a first monitoring port. An optical power splitter arrangement and an optical receiver are disposed within the housing. The splitter arrangement splits optical signals received at the input port onto one or more output lines and one or more monitoring lines. The output lines are routed to the output ports and the monitoring lines are routed to the optical receiver. The optical receiver measures the power of optical signals received from the first monitoring line and provides a measurement signal to the first monitoring port of the housing.

Abstract: An optical communication system that connects a plurality of user-side optical line terminating apparatuses (hereinafter referred to as ONUs) to a station-side optical line terminating apparatus (hereinafter referred to as OLT) using a common optical fiber, wherein the ONU as at least a part of the ONUs includes a transceiver having a power saving function for inactivating a transmitting unit while supplying electric power to a receiving unit and a control apparatus that transmits support information of the power saving function to the OLT via the transceiver, and the OLT includes a control apparatus that generates transmission allowance information of upstream communication based on the support information of the power saving function and a transceiver that receives the support information of the power saving function and transmits the transmission allowance information to the ONU.

Abstract: A communication system includes a transmitter that combines and transmits a first signal light and a dummy light having a wavelength different from the first signal light; a first amplifier that amplifies a light transmitted by the transmitter to a constant power; a communication device that separates the dummy light from the light amplified by the first amplifier, has a variable transmittance and allows the separated dummy light to pass through, and combines and transmits the passed dummy light and a second signal light having a wavelength different from the dummy light; a second amplifier that amplifies a light transmitted by the communication device to a constant power; a receiver that receives the second signal light included in the light amplified by the second amplifier; and a controller that controls the transmittance.

Abstract: The embodiments provide an automatic bias control method and apparatus for an optical transmitter. The apparatus includes: a detecting unit configured to monitor output optical power of an I/Q modulator of the optical transmitter; a calculating unit configured to calculate bias voltage indicating values of the I modulator, Q modulator and phase modulator of the I/Q modulator according to the output optical power and known modulation data; and an adjusting unit configured to adjust respectively Direct-Current (DC) bias voltages of the I modulator, Q modulator and phase modulator according to the bias voltage indicating values of the I modulator, Q modulator and phase modulator. With the embodiments, known modulation data are used to realize automatic bias control by monitoring the evenness of distribution of the power of output optical signals of the transmitter in the four quadrants of an I/Q plane.

Abstract: The invention relates to a method for monitoring a passive optical network having a tree-like structure with a main line and a plurality of branches. The method includes transmitting a wake-up signal from an optical line termination (OLT) arranged in the main line to a plurality of monitoring units arranged in the branches. The method also includes detecting the wake-up signal and listening to information requests from the OLT in the monitoring units during a listening time interval after the detection of the wake-up signal. The method further includes transmitting an information request to be received in the listening time interval from the OLT to the monitoring units. The method additionally includes receiving the information request in the monitoring units during the listening time interval, one of the monitoring units which is addressed by the information request transmitting a response message back to the OLT.

Abstract: An apparatus comprising a receiver optical subassembly (ROSA) configured to receive an optical signal, wherein the ROSA comprises an optical-electrical (O/E) converter configured to convert the optical signal into an electrical signal, and a processor coupled to the ROSA and configured to calibrate an O/E converter bias, wherein calibrating the O/E converter bias comprises reading an initial O/E converter dark current measurement, adjusting the O/E converter bias with a voltage step, reading an adjusted O/E converter dark current measurement after the voltage step adjustment, and monitoring an O/E converter dark current change rate by subtracting the initial O/E converter dark current measurement from the adjusted O/E converter dark current measurement.

Abstract: A method and apparatus for performing an automatic power adjustment wherein a signal power level of an optical signal transmitted by an optical transceiver via an s optical span to a far-end device is adjusted automatically in response to a determined span loss of the optical span to achieve a predetermined desired receive signal power level of the optical signal at the far-end device.

Abstract: A method and apparatus for performing an automatic power adjustment wherein a signal power level of an optical signal transmitted by an optical transceiver via an optical span to a far-end device is adjusted automatically in response to a determined span loss of the optical span to achieve a predetermined desired receive signal power level of the optical signal at the far-end device.

Abstract: An optical transmission apparatus includes a reception part for receiving a wavelength division multiplexed (WDM) signal reached via optical amplifiers; a measuring part for measuring an optical power level of each wavelength of the WDM signal received by the reception part; a determination part for determining whether an amount of tilt of the WDM signal calculated based on measurement results of the measuring part is suitable or not; an operation part for calculating the tilt correction amount to be applied to tilt correction processing performed by the optical amplifiers if the amount of tilt of the WDM signal is not suitable; and a notification part for notifying the optical amplifiers of the tilt correction amount.

Abstract: An optical intensity control system for use with an optical switch providing individual signal paths between input and output ports. The system has optical splitters connectable to output multiplexers of the switch and has variable optical intensity controllers (VOICs) for insertion into the individual signal paths to individually control the intensity of optical signals present in the signal paths via intensity control signals. An equalizer connected to the splitters and the VOICs produces an estimate of the optical power of each individual switched optical signal and generates the intensity control signals. The equalizer is adapted to controllably isolate individual switched optical signals. In this way, individual and independent control of the power on each optical channel is provided.

Abstract: An optical receiver system includes a power adjustment device, an optical receiver, and a controller. The power adjustment device adjusts the power of an optical input signal in accordance with adjustment instructions. The optical receiver converts the power-adjusted optical input signal into an electrical signal that corresponds to a desired channel of the optical input signal. The optical receiver includes an electronic amplifier that amplifies the electrical signal using a gain value, and the amplified electrical signal preferably operates around a voltage value Vopt. The controller determines adjustment instructions such that the power adjustment device adjusts the optical input signal to a target optical power level that corresponds to Vopt for the amplified electrical signal, wherein the adjustment instructions are derived from the amplified electrical signal.

Abstract: A level transition determination circuit includes a multi-phase clock generator, an oversampling unit, and a state detection circuit. The multi-phase clock generator is used for receiving an input clock signal and generating S×N clock signals, in which S and N are integers. Each clock signal is synchronized to the input clock signal and has a different delay time. The oversampling unit is used for performing N-times oversampling on M bit periods of the serial input data according to the clock signals, so as to generate M×N sampled values in parallel during the M bit periods. The state detection circuit is used for receiving (M×N)+1 sampled values and generating N detection signals by detecting level transitions between adjacent sampled values of the (M×N)+1 sampled values and the level transition results.

Abstract: An optical transmission apparatus includes a splitter configured to split an input optical signal into a first optical signal and a second optical signal, a signal length determiner configured to determine a signal length of the first optical signal per unit time, an optical power detector configured to detect an optical power of the first optical signal per unit time, a delay unit configured to delay the second optical signal, an optical amplifier configured to amplify the second optical signal delayed by the delay unit, a first excitation light source configured to generate an excitation light to be supplied to the optical amplifier, and a first excitation light power adjustor configured to adjust an optical power of the excitation light to be supplied to the optical amplifier in accordance with the signal length of the first optical signal and the optical power of the first optical signal.

Abstract: An optical transceiver and/or optical network, and methods of monitoring optical transceivers, may be useful for increasing the dynamic range and/or determining the received signal strength and/or link budget of the optical transceiver and/or a different optical transceiver in the optical network. The circuitry generally comprises a photodiode configured to generate a first current responsive to an optical signal, a current mirror configured to produce a second current equal or proportional to the first current, and a nonlinear element configured to produce a first voltage from the first current.

Abstract: An optical module for receiving light according to a digital coherent optical transmission scheme includes two optical fibers, and a monitor PD. The optical signal processing circuit includes a substrate, an optical waveguide layer made up of a core and a clad layer stacked on top of the substrate, and fixtures stacked on top of the clad layer on the one end, and is provided with a light shield member which spans the substrate, the clad layer, and the edge face of the fixture on the edge face of the optical signal processing circuit that faces the monitor PD, and which includes an aperture unit aligned with the given site where the diverted signal light is output.

Abstract: A bidirectional monitor module includes a 2×2 optical coupler configured to output input light that is input from a first port to a second port and drop the input light input from the first port to a third port and also output input light that is input from the second port to the first port and drop the input light input from the second port to a fourth port; an optical output unit configured to output one of light that is dropped and output from the third port and light that is dropped and output from the fourth port; and a monitor unit configured to monitor optical power of the light output from the optical output unit.

Abstract: An ONU includes a power-interruption detecting unit configured to detect power interruption of the ONU, a transmitting and receiving unit capable of being set in a power saving state, and a PON-side control unit configured to notify an OLT of, as power saving return information, a power holding time during occurrence of the power interruption of the ONU and a startup time, which is time until the transmitting and receiving unit returns from the power saving state, and, when the power-interruption detecting unit detects the power interruption, transmit a power interruption notification to the OLT. The OLT includes the PON control unit configured to determine, based on the power saving return information, whether the ONU can transmit the power interruption notification when the power interruption occurs in the power saving state.

Abstract: A system configured to maintain a consistent local-oscillator-power-to-primary-signal-power ratio (LO/SIG ratio).

Abstract: The object of the present invention is to reliably prevent deterioration and failure of reception relevant parts in a transmission apparatus on a reception side without using an attenuator. An output value control method that controls an output value of output information transmitted from each of transmission apparatuses, in which a transmission apparatus transmits the output information having a minimum output value as the output value to the other transmission apparatus, and when the output information does not reach the other transmission apparatus, the transmission apparatus repeats transmission of the output information after increasing the own output value by adding a predetermined value to a previous output value, and then the other transmission apparatus that has received the output information calculates the output value of the transmission apparatus, and notifies the calculated output value of the transmission apparatus as an appropriate output value to the transmission apparatus.

Abstract: Techniques are provided to estimate a distance of one received optical subchannel to one or both of its neighbor (adjacent) subchannels. An optical field comprised of a plurality of subchannels of optical signals at respective wavelengths is received on an optical fiber. Using coherent optical reception in conjunction with analog-to-digital conversion, the received optical field is converted to digital complex valued data. The digital complex valued data is transformed to the frequency domain to produce spectrum data. Using either a peak method or a gap method, a distance or spacing is computed between a subchannel of interest among the plurality of subchannels and at least one neighbor subchannel based on the spectrum data.

Abstract: An optical access network (5) comprises optical network units (10) connected to a node (40). A monitoring unit (35) determines information indicative of energy consumption at the optical network unit (10) over a period of time. An optical network unit (10) can operate in operating states/modes which differ in their energy consumption. Monitoring unit (35) can determine the information by determining a time that an optical network unit spends in the different operating states/modes. Monitoring unit (35) can use a state machine (31) at the node (40) which represents the optical network unit (10). An optical network unit (10) can locally record time spent in states/modes and forward this to the monitoring unit (35). An optical network unit (10) can locally monitor energy consumption and forward this to the monitoring unit (35). An operational parameters of the access network (5) can be modified based on the information determined by the monitoring unit (35).

Abstract: A method includes outputting an optical signal from an optical transmitter; causing the optical signal to propagate through equipment of an optical communication site and to loop back to an optical receiver; measuring optical powers, respectively, based on taps proximate to the optical transmitter and the optical receiver; calculating an optical power loss based on the optical powers measured; determining whether the optical power loss is an acceptable value; and indicating when the optical power loss is not the acceptable value.

Abstract: A communication system and method utilizing an infrared signal emitter communicating a predefined signal, and an infrared signal receiver capable of receiving such predefined signal, distinguishing such predefined signal within a field of view of the infrared signal receiver, and providing output indicating the location of the infrared signal emitter within the field of view of the infrared signal receiver.

Abstract: An optical component includes: a glass capillary; an optical fiber for light to be measured which is inserted into the through-hole of the glass capillary; at least one optical fiber for leak light which is inserted into the through-hole of the glass capillary; and an output optical fiber having one end connected to one end of the optical fiber for light to be measured, wherein light emitted from the output optical fiber enters into the optical fiber for light to be measured from the one end side thereof, and a part of light that has been emitted from the output optical fiber that does not enter into the optical fiber for light to be measured, that is, leak light enters into the optical fiber for leak light from the one end side thereof.

Abstract: An optical transmitter includes: an optical modulator configured to generate an optical signal from a plurality of transmission signals; a crosstalk monitor configured to monitor crosstalk between the plurality of transmission signals by using the optical signal; and a crosstalk canceller configured to correct the plurality of transmission signals based on a result of monitoring by the crosstalk monitor.

Abstract: A circuit, optical transceiver and/or methods for using the same may be useful for determining average power, extinction ratio, and/or modulation amplitude when monitoring an optical transceiver and/or optical network. The circuit generally comprises a photodiode configured to generate a first current responsive to an optical signal, a current mirror coupled to a first terminal of the photodiode, and a detector coupled to a second terminal of the photodiode. The current mirror is configured to produce a second current equal to or proportional to the first current, and the detector is configured to determine a power or amplitude of the optical signal. Further, the present scheme may communicate information using a low speed signal superimposed on or combined with the relatively high speed optical signal.