387 results about "Optical signal to noise ratio" patented technology

An apparatus and method for measuring optical signal to noise ratio (OSNR) in a node of an optical data network is disclosed. A peak power level and an average power level are measured for an optical input to an optical detector. The OSNR is determined by selecting an OSNR having the peak power level and the average power level associated with an optical signal traversing an optical path having attenuation and optical amplifier noise.

An optical reception circuit generates optical electric field data by performing coherent reception of an optical signal transmitted via an optical fiber transmission line. An FIR filter filters the optical electric field data so that the optical signal is equalized. A quality monitor unit calculates the average value and the standard deviation value of the amplitude of the optical signal on the basis of the equalized optical electric field data, and further calculates an optical signal-to-noise ratio on the basis of the calculated values.

An OSNR monitor device includes an optical receiver including a delay interferometer which inputs an optical signal in accordance with a given bandwidth and outputs two optical signals and causes the optical signals to interfere with each other and optical detectors which outputs currents in accordance with optical powers of the optical signals output from the interferometer, an optical power monitor configured to obtain the optical powers of the optical signals received by the optical detectors included in the optical receiver, and an OSNR calculator configured to calculate an optical signal-to-noise ratio in accordance with the optical powers obtained from the optical power monitor and the reception bandwidth.

The invention discloses an optical signal to noise ratio (OSNR) detecting method. The method comprises the steps that a wavelength label signal is loaded in an optical signal by a wavelength label loading end, the loading-modulating depth of the wavelength label signal is transmitted to an OSNR detecting end by a wavelength label channel or an optical monitoring channel; the OSNR detecting end obtains the loading-modulating depth of the wavelength label signal loaded in each wavelength optical signal; the wavelength label signal is analyzed to obtain the current modulating depth of the wavelength label signal; and the OSNR value of each wavelength optical signal is obtained according to the loading-modulating depth and the current modulating depth of the wavelength label signal. The invention simultaneously discloses an OSNR detecting system and OSNR detecting equipment. According to the invention, the scheme is suitable for OSNR test of current high-speed-ratio optical signals being 40G, 100G and the like and particularly suitable for the OSNR test of polarization multiplexing optical signals.

A method for determining an optical signal-to-noise ratio penalty as a measure for a quality of an optical signal transmitted via an optical link between a source optical node and a destination optical node in an optical network, the method includes collecting information of the optical link; determining a configuration parameter Pconf of the optical link based on the information of the optical link; adjusting the configuration parameter Pconf to an adjusted configuration parameter P′conf according to linear impairments in the optical link; and determining the optical signal-to-noise ratio penalty based on a non-linear function of the adjusted configuration parameter P′conf, the non-linear function accounting for non-linear impairments in the optical link.

The invention discloses a method for monitoring the OSNR (optical signal to noise ratio) in a high-speed DWDM (dense wavelength division multiplexing) system. The method comprises the following steps: loading a wavelength label for each wavelength optical signal outputted by a sending end, conducting broadband filtering and narrow-band filtering on the optical signal loaded with the wavelength label, measuring the total power of the optical signal by a digital signal processing technology, calculating the power of the alternating component, and calculating the OSNR according to the total power of the optical signal, the power of the alternating component and characteristic parameters of a filter. The invention further discloses a device for monitoring the OSNR in the high-speed DWDM system; and with the application of the method and the device, the defects of an existing interpolation method and an existing palarization multiplexing are overcome, and the OSNR in the high-speed wavelength division multiplexing system is monitored.

The invention discloses a polarization interference-based in-band optical signal-to-noise ratio detection method and device. The method comprises the following steps of: dividing an input optical signal into two beams, of which one beam is used for measuring total power of the optical signal, and the other beam is used for measuring noise power in the optical signal; performing polarization beam splitting on the optical signal to obtain two branches which are perpendicular to each other in the polarization direction; adding time delay in one path of the two branches; combining the optical signals of the two branches together to obtain an optical signal with a polarization state varying along with frequency; adjusting a polarization angle of a polarizer to realize complete destructive interference of some frequency points so as to obtain an optical spectrum comprising noise power information; and calculating the optical signal-to-noise ratio according to the obtained total power of the optical signal and the noise power. According to the method and the device, the OSNR (Optical Signal to Noise Ratio) of the signal in a dynamic optical network and a high-speed optical fiber communication system can be detected, the detection range is 9-35 dB, the detection is not affected by the signal polarization state, optical fiber dispersion and polarization mode dispersion, the method and the device are transparent to a signal modulation format and a transmission rate, and the defects of the conventional OSNR detection method are overcome.

The invention relates to an optical parametric amplifier-based all-optical signal quality monitor, which is used for the online monitoring of optical signal chromatic dispersion, an optical signal to noise ratio and polarization mode dispersion. The monitor comprises a pre-optical amplifier, a semiconductor laser, a coupler, an optical parametric amplifier, an output optical filter and an optical power meter. The semiconductor laser sends out low-power continuous detection light; the continuous detection light and signal light amplified by the pre-optical amplifier are subjected to beam combination by the couple and then injected into the optical parametric amplifier; the optical parametric amplifier transfers the energy of the signal light to the detection light and idle light based on a one-order four-wave mixing effect; and the detection light and the idle light output by the optical parametric amplifier are metered by the optical power meter after passing through the output optical filter. The monitor has the advantages of high response speed, high flexibility, wide working wave band and can respond to the signal rate and modulation format at any time through monitoring; and the monitor is applicable for the online monitoring of quality parameters of signals with the single channel speed of over 100 Gb / s.

An apparatus and method for measuring optical signal-to-noise ratio in optical communications includes (1) a variable optical band-pass filter (VOBPF) that passes the amplified output beam when the beam wavelength is the same as the passing wavelength of the VOBPF; (2) a 1x4 beam distributor for distributing the passing beam of the VOBPF into four streams; (3) a measuring device for measuring Stokes parameters S0, S1, S2, S3 from the four distributed beams; (4) a calculating device for calculating the optical signal power by finding the power of the polarized component of the amplified output beam from the Stokes parameters S1, S2, and S3; (5) a calculating device for calculating the noise power by finding the power of the noise included in the amplified output beam from Stokes parameter S0 and the optical signal power; and (6) a dividing device for calculating the ratioat the passing wavelength.

A method and apparatus for improving the accuracy of in-band OSNR measurements using a conventional polarization extinction or polarization-nulling method. In particular, the severe degradations of the polarization extinction that result from slow and fast polarization fluctuations in the optical signal components during the in-band OSNR measurement are substantially mitigated by rapidly and / or randomly changing the state of polarization prior to conventional polarization control and filtering.

A WDM optical network comprising a plurality of nodes has a first apparatus for optical analysis at the site of a first optical amplifier upstream of the first node, a second apparatus for optical analysis at the site of a second optical amplifier at the downstream output of the first node, and a third apparatus for optical analysis at the site of a third optical amplifier further downstream of the first node, where knowledge of the optical sin to noise ratio (OSNR) is desired. The first, second and third apparatus are for measuring the signal level at frequencies both at and in-between the channel frequencies. The signal levels at the channel frequencies and between the channel frequencies at the first, second and third apparatus are used to derive the OSNR at the third apparatus. This enables the OSNR to be measured accurately at any site in the network, using calculations in which noise shaping of the nodes can be factored in to the calculation of OSNR.