Abstract: There is provided a video distribution system, a video distribution method, and a display terminal enabling more reliable video distribution, the video distribution system including: an image acquisition unit that acquires a low-resolution image from a low-resolution camera while acquiring a high-resolution image from a high-resolution camera; an abnormality determination unit that determines whether or not there is an abnormality in any one of a first signal representing the low-resolution image and a second signal representing the high-resolution image; and a transmission control unit that transmits first synthetic images to a display terminal in a case where it is determined that there is no abnormality, the first synthetic images having continuity between the low-resolution image and the high-resolution image, and transmits second synthetic images to the display terminal in a case where it is determined that there is an abnormality, the second synthetic images substantially reproducing continuity by repla

Abstract: Methods and systems for in-band OSNR monitoring include a tunable optical filter to scan a passband of a desired optical channel. The optical power over the passband is measured and digitized to power waveform data. The power waveform data is processed with a digital signal processor to calculate OSNR. Additionally, various implementations accommodate dual polarization modulation formats using a parallel architecture and an alternating sequential architecture.

Abstract: Methods and systems for mitigating spectral offset may use a scanning optical filter to scan different frequencies (or wavelengths) in a signal bandwidth of an optical channel. The maximum optical power value for the optical channel may be accurate determined as well as an effective wavelength corresponding to the maximum optical power value.

Abstract: Methods and systems for in-band OSNR monitoring include a tunable optical filter to scan a passband of a desired optical channel. The optical power over the passband is measured and digitized to power waveform data. The power waveform data is processed with a digital signal processor to calculate OSNR. Additionally, various implementations accommodate dual polarization modulation formats using a parallel architecture and an alternating sequential architecture.

Abstract: Methods and systems for mitigating spectral offset may use a scanning optical filter to scan different frequencies (or wavelengths) in a signal bandwidth of an optical channel. The maximum optical power value for the optical channel may be accurate determined as well as an effective wavelength corresponding to the maximum optical power value.

Abstract: The present disclosure includes a computer-implemented method of correcting a measured optical signal-to-noise ratio (OSNR) comprising receiving an optical signal and measuring OSNR of the optical signal using an interferometric OSNR monitor device. The method also includes applying a correction table to the measured OSNR to generate a corrected OSNR using a controller, the correction table comprising a correction function to counteract an artifact in the measured OSNR. The method also includes storing the corrected OSNR in a non-transitory computer-readable medium. The present disclosure also includes associated devices applying the correction table and methods of generating the correction table.

Abstract: The present disclosure includes a method of determining optical signal-to-noise ratio (OSNR) of a signal, comprising separating one polarization component from a plurality of polarization components in an optical signal, selecting one wavelength from a plurality of wavelengths in the optical signal, delaying a first portion of the one polarization component of the one wavelength of the optical signal, shifting a phase of the first portion by a first amount and the first amount plus pi radians, causing the first portion to interfere with a second portion, measuring a power of the interference of the first and second portions, receiving the power of the interference, and comparing the power of the interference when the phase is shifted by the first amount with the interference when the phase is shifted by the first amount plus pi radians to determine OSNR. The present disclosure also includes associated devices.

Abstract: The present disclosure includes a computer-implemented method of correcting a measured optical signal-to-noise ratio (OSNR) comprising receiving an optical signal and measuring OSNR of the optical signal using an interferometric OSNR monitor device. The method also includes applying a correction table to the measured OSNR to generate a corrected OSNR using a controller, the correction table comprising a correction function to counteract an artifact in the measured OSNR. The method also includes storing the corrected OSNR in a non-transitory computer-readable medium. The present disclosure also includes associated devices applying the correction table and methods of generating the correction table.

Abstract: In an optical amplification apparatus an optical amplifier amplifies an optical signal at set gain. An equalizer changes loss of the amplified optical signal according to wavelengths. A processor controls the equalizer so as to make the equalizer have a loss-wavelength characteristic corresponding to a gain tilt of the optical amplifier which occurs according to the set gain.

Abstract: An optical adding and dropping device includes a drop section including an input port and having a through port and a plurality of drop ports set as output ports, a first multiplexer adapted to multiplex light from the through port and light from a plurality of add ports, and a spectrum foot removing section provided on the input side of the first multiplexer and adapted to remove a foot of a spectrum of light to be inputted from the add ports to the first multiplexer. The optical adding and dropping device can be configured at a low cost while it has adding and dropping functions.

Abstract: An optical network interconnect device interconnects a first WDM network for transmitting a WDM optical signal with first wavelength spacing and a second WDM network for transmitting a WDM optical signal with second wavelength spacing that is wider than the first wavelength spacing. The optical network interconnect device includes a filter to remove a wavelength component which is not used in the second WDM network from an WDM optical signal transferred from the first WDM network to the second WDM network.

Abstract: The present disclosure includes a method of determining optical signal-to-noise ratio (OSNR) of a signal, comprising separating one polarization component from a plurality of polarization components in an optical signal, selecting one wavelength from a plurality of wavelengths in the optical signal, delaying a first portion of the one polarization component of the one wavelength of the optical signal, shifting a phase of the first portion by a first amount and the first amount plus pi radians, causing the first portion to interfere with a second portion, measuring a power of the interference of the first and second portions, receiving the power of the interference, and comparing the power of the interference when the phase is shifted by the first amount with the interference when the phase is shifted by the first amount plus pi radians to determine OSNR. The present disclosure also includes associated devices.

Abstract: A phase shift unit provides a prescribed phase difference (?/2, for example) between a pair of optical signals transmitted via a pair of arms constituting a data modulation unit. A low-frequency signal f0 is superimposed on one of the optical signals. A signal of which phase is shifted by ?/2 from the low-frequency signal f0 is superimposed on the other optical signal. A pair of the optical signals is coupled, and a part of which is converted into an electrical signal by a photodiode. 2f0 component contained in the electrical signal is extracted. Bias voltage provided to the phase shift unit is controlled by feedback control so that the 2f0 component becomes the minimum.

Abstract: A wavelength selective switch includes a wavelength dispersing element, a wavelength converging element, multiple transmission control elements, and a controller. The wavelength dispersing element performs wavelength dispersion of input signal light. The transmission control element divides input signal light into wavelength bands within a channel band and transmits or cuts off the divided input signal light. The wavelength converging element converges signal light having respective wavelengths produced from the transmission control elements for output. The controller controls a transmittance of the transmission control element of at least one of the low and high frequency sides in a channel band.

Abstract: An optical transmitter is provided for transmitting a wavelength multiplexed signal comprising an intensity modulation optical signal and a phase modulation optical signal through a transmission line. The optical transmitter includes a bit time difference given signal generator for generating at least two optical signals having a bit time difference therebetween, from the wavelength multiplexed signal. The optical transmitter further includes a wavelength multiplexed signal output unit to which at least two optical signals are input from the bit time difference given signal generator, and which generates and outputs a wavelength multiplexed signal in which the bit time difference was given between the phase modulation optical signal and the phase modulation optical signal.

Abstract: An OADM in a wavelength division multiplexing transmission system includes a wavelength selection switch that selects a predetermined wavelength from a multiple optical signal obtained by multiplexing a phase modulated signal and an intensity modulated signal and outputs the selected wavelength signal to a predetermined output port. The wavelength selection switch has a different delay for each wavelength of the multiple optical signal. For example, the wavelength selection switch includes a mirror array. Optical paths from the surfaces of mirrors arranged on the mirror array to the diffraction grating are different in the case of adjacent mirrors.

Abstract: An optical transmission apparatus according to the present invention comprises: a plurality of optical modulating sections serially connected to each other via optical fibers; driving sections corresponding to the optical modulating sections; delay amount varying sections that provide variable delay amounts for modulating signals to be input to the driving sections, to adjust timing between drive signals to be provided for the optical modulating sections; temperature monitoring sections that monitor the temperature of each of the optical fibers and the like; and a delay amount control section that controls the delay amount in each of the delay amount varying sections based on the monitored temperatures.

Abstract: In a dispersion compensating apparatus, a reference identifying unit identifies a reference (X dB down) that makes a penalty lower than a predetermined value in accordance with optical signal information and a reference identifying table, and a VIPA plate temperature adjusting unit adjusts a refractive index of a VIPA plate by modifying a temperature of the VIPA plate so that a transmission center wavelength derived from the reference matches the wavelength defined by an ITU-T Grid. If a dispersion compensation value setting unit performs an optimal residual dispersion value search, the VIPA plate temperature adjusting unit determines if a filtering penalty is lower than a predetermined value in accordance with a penalty management table. If the filtering penalty is lower than the predetermined value, temperature adjustment of the VIPA plate is not performed.

Abstract: Where add optical signals have k different bit rates, an add controller is connected to k (<N) of N input ports and sends the add optical signals to the k input ports to perform add control. A drop controller is connected to m (<M) of M output ports and performs drop control on optical signals from the m output ports. The k input ports of an N×M wavelength selective switch and the add controller are connected by k links (L1 to Lk) which have introduced therein dispersion compensators for compensating chromatic dispersions of the add optical signals with the respective bit rates. The add controller selects a link through which an add optical signal is to be passed for dispersion compensation, and sends the signal to the N×M wavelength selective switch via the selected link.

Abstract: A wavelength selective switch includes a wavelength dispersing element, a wavelength converging element, multiple transmission control elements, and a controller. The wavelength dispersing element performs wavelength dispersion of input signal light. The transmission control element divides input signal light into wavelength bands within a channel band and transmits or cuts off the divided input signal light. The wavelength converging element converges signal light having respective wavelengths produced from the transmission control elements for output. The controller controls a transmittance of the transmission control element of at least one of the low and high frequency sides in a channel band.