Abstract: A method of controlling a transmission signal, includes transmitting a training signal including four polarization states having a given relation; and performing rotation control and transmission power level control of a polarization component of a data signal, based on a rotation control matrix for a polarization state and an inverse-operation control matrix for a power level imbalance, which are estimated from Stokes parameters related to input power level present on a Poincare sphere acquired from the training signal and Stokes parameters related to output power level present on the Poincare sphere.

Abstract: An optical signal-to-noise ratio measurement device includes a measurement unit and a determination unit and measures an optical signal-to-noise ratio of an optical signal including a fixed pattern in a specified cycle. The measurement unit measures an optical signal-to-noise ratio of the optical signal respectively in a plurality of time sections in a measurement period so as to generate a plurality of measured values, a length of the measurement period being the same or substantially the same as a length of the specified cycle. The determination unit selects, from the plurality of measured values generated by the measurement unit, at least one measured value other than a worst measured value in the plurality of measured values, and determines an optical signal-to-noise ratio of the optical signal based on the selected at least one measured value.

Abstract: An imprint apparatus comprises a mold holder configured to move while holding the mold, and a substrate holder including a plurality of suction regions for chucking the substrate and configured to move while holding the substrate. When performing the mold separation, among the plurality of suction regions, a suction force of a suction region at a position where the mold is to be separated from the imprint material is made weaker than a suction force of a suction region on a peripheral side of the substrate than the position where the mold is to be separated, and the mold holder is tilted after at least one of the mold holder and the substrate holder is moved by a predetermined amount so as to widen a gap between the mold and the substrate.

Abstract: An optical signal-to-noise ratio (OSNR) measuring device includes a processor, wherein the processor executes a process. The process includes: converting an optical signal to an electrical signal; first acquiring a signal intensity from the electrical signal; second acquiring a noise intensity of a predetermined frequency band from the electrical signal; performing a digital conversion on the noise intensity; and computing an OSNR of the optical signal based on the signal intensity and the converted noise intensity. The predetermined frequency band is a frequency band including a folding noise that occurs when the digital conversion is performed.

Abstract: There is provided a transmitter configured to transmit a symbol in a constellation, the symbol corresponding to data to be transmitted, the transmitter including a memory in which key information for generating pseudo random numbers are stored, and a processor coupled to the memory and configured to generate a pseudo random number every the symbol, select data patterns every data areas in which information of types of a data pattern are arranged, based on the pseudo random number, so that a distance between the data patterns to be selected is more than a predetermined value on a plane on which the data areas are continuously arranged every a horizontal axis and a vertical axis of the constellation, and determine the symbol to be transmitted, based on the selected data patterns according to a position of a data pattern corresponding to the data to be transmitted in the constellation.

Abstract: An optical transmission apparatus includes a wavelength variable filter whose transmission light wavelength is variable; a receiver that receives light, the light being sent from another optical transmission apparatus and passing through the wavelength variable filter; a transmitter that sends to the another optical transmission apparatus, a utilization permission request for a second wavelength corresponding to a first wavelength of the light received by the receiver, the transmitter sending the utilization permission request as light of the second wavelength and in a form of a tone signal of a predetermined frequency; and a controller that, when receiving from the another optical transmission apparatus, a utilization permission notification of the second wavelength for a sender of the utilization permission request, configures a wavelength of a main signal to the second wavelength, the main signal being sent from the transmitter to the another optical transmission apparatus.

Abstract: A transmission apparatus including: a branch circuit that branches a signal including first data and second data superimposed on the first data into two signals; a limiting amplifier that amplifies one signal in the two signals; a linear amplifier that amplifies another signal in the two signals; a first detector that detects the first data from the amplified one signal; and a second detector that detects the second data from the amplified another signal and the amplified one signal.

Abstract: A transmitter generates a frequency-modulated CW light so as to transmit it to a path. A receiver receives the CW light that has passed through passband filters included in the path. The receiver includes a processor. The processor measures an optical power of the received CW light every time a center frequency of the CW light is changed and transmitted by the transmitter. The processor calculates transmission characteristics of the CW light that has passed through the passband filters, on the basis of an average value of the optical power that corresponds to a center frequency of the CW light and on the basis of an amplitude component that indicates an amount of change in the optical power, the average value and the amplitude component being obtained as a result of the measurement.

Abstract: There is provided an apparatus configured to estimate optical transmission performance in a transmission path of an optical signal, the apparatus including a memory, and a processor coupled to the memory and the processor configured to acquire a first index related to a first transmission performance of an optical signal transmitted through a span group between a first node and an n-th node and a second index related to a second transmission performance of an optical signal transmitted through a span or a span group between the first node and an m-th node, wherein n is an integer of 3 or more, and m is the integer satisfying m<n, and estimate a third index related to a third transmission performance of an optical signal to be transmitted through a span between the m-th node and the n-th node, based on the first index and the second index.

Abstract: An optical signal-to-noise ratio measurement device includes a measurement unit and a determination unit and measures an optical signal-to-noise ratio of an optical signal including a fixed pattern in a specified cycle. The measurement unit measures an optical signal-to-noise ratio of the optical signal respectively in a plurality of time sections in a measurement period so as to generate a plurality of measured values, a length of the measurement period being the same or substantially the same as a length of the specified cycle. The determination unit selects, from the plurality of measured values generated by the measurement unit, at least one measured value other than a worst measured value in the plurality of measured values, and determines an optical signal-to-noise ratio of the optical signal based on the selected at least one measured value.

Abstract: An imprint apparatus molds an uncured resin on a substrate and cures the resin to form a pattern of the cured resin on the substrate. The apparatus includes a mold holding unit that holds the mold, a substrate holding unit that holds the substrate, a deforming unit that deforms the mold held by the mold holding unit into a convex shape toward the substrate, a driving unit that changes an attitude of the mold or the substrate during a releasing operation in which the mold deformed into the convex shape is released from the resin to thereby make the position of a contact region at which the mold is brought into contact with the resin movable, a measuring unit that acquires image information indicating a state of the contact region, and a control unit configured to control the operation of the driving unit based on the image information.

Abstract: A method of controlling a transmission signal, includes transmitting a training signal including four polarization states having a given relation; and performing rotation control and transmission power level control of a polarization component of a data signal, based on a rotation control matrix for a polarization state and an inverse-operation control matrix for a power level imbalance, which are estimated from Stokes parameters related to input power level present on a Poincare sphere acquired from the training signal and Stokes parameters related to output power level present on the Poincare sphere.

Abstract: There is provided a transmitter configured to transmit a symbol in a constellation, the symbol corresponding to data to be transmitted, the transmitter including a memory in which key information for generating pseudo random numbers are stored, and a processor coupled to the memory and configured to generate a pseudo random number every the symbol, select data patterns every data areas in which information of types of a data pattern are arranged, based on the pseudo random number, so that a distance between the data patterns to be selected is more than a predetermined value on a plane on which the data areas are continuously arranged every a horizontal axis and a vertical axis of the constellation, and determine the symbol to be transmitted, based on the selected data patterns according to a position of a data pattern corresponding to the data to be transmitted in the constellation.

Abstract: An optical transmitting device includes: a symbol determining circuit that determines one base from a plurality of bases for each input of plain text corresponding to one symbol and determines a modulation position of the symbol according to the plain text and the base; a shift circuit that randomly shifts the modulation position within a signal identification region set based on the base; and a modulator that modulates light emitted from a light source, according to a shifted position shifted by the shift circuit.

Abstract: An optical level control apparatus includes an input port, an output port, an optical device to assume a state of outputting light inputted to the input port from the output port and a state of not outputting the light inputted to the input port from the output port; a detector to detect an intensity of the light inputted to the input port, and a control unit to detect an input of an optical burst signal to the input port on the basis of a result of detecting the intensity of the light and to control the optical device so that the signal, in which to eliminate a field extending up to an elapse of a period of first time equal to or shorter than laser ON time period of the signal from a head of the signal with its input being detected, is output from the output port.

Abstract: A transmission apparatus including: a branch circuit that branches a signal including first data and second data superimposed on the first data into two signals; a limiting amplifier that amplifies one signal in the two signals; a linear amplifier that amplifies another signal in the two signals; a first detector that detects the first data from the amplified one signal; and a second detector that detects the second data from the amplified another signal and the amplified one signal.

Abstract: A transmission characteristics monitoring device monitors transmission characteristics of an optical transmission path between nodes. The device detects an average power of the frequency modulated optical signal and a slope of the transmission characteristics; generates a slope function that represents a slope of the transmission characteristics between first and second frequencies; generates a corrected power value by adding an integral of the slope function to a first power measurement value detected at the first frequency; calculates the transmission characteristics at the second frequency based on a second power measurement value detected at the second frequency when the difference between the second power measurement value and the corrected power value is smaller than a specified threshold; and calculates the transmission characteristics at the second frequency based on the corrected power value when the difference is greater than the specified threshold.

Abstract: An optical receiver includes: a tunable filter configured to partially transmit a wavelength-multiplexed optical-signal including a first optical-signal having a first wavelength, a second optical-signal having a second wavelength, and a third optical-signal having a third wavelength, with a frequency-modulated signal superimposed on each of the first to third optical-signals; a photo detector configured to detect an optical-power of the wavelength-multiplexed optical-signal transmitted through the tunable filter; and a superimposed signal detector configured to detect the frequency-modulated signal superimposed on the first optical-signal, based on an amplitude-modulated signal according to a variation in the optical-power on a first filter setting where both of the first optical-signal and the second optical-signal transmit through the tunable filter, and an amplitude-modulated signal according to a variation in the optical-power on a second filter setting where both of the first optical-signal and the thir

Abstract: A determination method for determining a pattern of a mold is disclosed. The pattern of the mold is used in imprint processing of forming a pattern on imprint material by performing the steps of pressing the imprint material on a substrate against the pattern of the mold in an atmosphere containing condensable gas to be liquefied due to compression, curing the imprint material, and releasing the mold from the imprint material. A processor calculates a shrinkage amount of the pattern on the imprint material. The pattern on the imprint material shrinks by desorbing condensate liquid, which is produced through liquefaction of the condensable gas between the imprint material and the pattern of the mold in the pressing step and which is dissolved in the imprint material, from the imprint material after completion of the pressing step.

Abstract: There is provided an apparatus configured to estimate optical transmission performance in a transmission path of an optical signal, the apparatus including a memory, and a processor coupled to the memory and the processor configured to acquire a first index related to a first transmission performance of an optical signal transmitted through a span group between a first node and an n-th node and a second index related to a second transmission performance of an optical signal transmitted through a span or a span group between the first node and an m-th node, wherein n is an integer of 3 or more, and m is the integer satisfying m<n, and estimate a third index related to a third transmission performance of an optical signal to be transmitted through a span between the m-th node and the n-th node, based on the first index and the second index.