Monitor circuit for monitoring property of optical fiber transmission line and quality of optical signal
AssigneeFujitsu Limited
InventorsShoichiro Oda, Takeshi Hoshida, Hisao Nakashima, Takahito Tanimura
Life of this patent
Estimating the term…
Abstract
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.
Claims13
A monitor circuit used along with an optical reception circuit for performing coherent reception of an optical signal, comprising:
- a digital equalization filter for generating equalized electric field data by filter computation to equalize the optical signal, for electric field data of the optical signal, which is obtained with the coherent reception;
- and
- a quality calculating unit for calculating a quality of the optical signal on the basis of the equalized electric field data.
A monitor circuit used along with an optical reception circuit for performing coherent reception of an optical signal transmitted via an optical fiber transmission line, comprising:
- a digital equalization filter for performing a filter computation to compensate for a property of the optical fiber transmission line, for electric field data of the optical signal, which is obtained with the coherent reception;
- and
- a property detecting unit for detecting the property of the optical fiber transmission line by using at least one parameter for determining a transfer function of the digital equalization filter to compensate for the property.
A monitor circuit used along with an optical reception circuit for performing polarization diversity coherent reception of an optical signal transmitted via an optical fiber transmission line, comprising:
- a plurality of digital equalization filters for performing a computation to compensate for a state change added to the optical signal in the optical fiber transmission line, for a pair of electric field data of the optical signal, which is obtained with the polarization diversity coherent reception;
- and
- a property detecting unit for detecting a property of the optical fiber transmission line according to parameters that are set to compensate for the state change in the plurality of digital equalization filters.
An optical receiver, comprising:
- an optical reception circuit for performing coherent reception of an optical signal;
- a digital equalization filter for generating equalized electric field data by filter computation to equalize the optical signal, for electric field data of the optical signal, which is obtained with the coherent reception;
- and
- a quality calculating unit for calculating a quality of the optical signal on the basis of the equalized electric field data.
An optical receiver, comprising:
- an optical reception circuit for performing coherent reception of an optical signal transmitted via an optical fiber transmission line;
- a digital equalization filter for performing a filter computation to compensate for chromatic dispersion of the optical fiber transmission line, for electric field data of the optical signal, which is obtained with the coherent reception;
- and
- a property detecting unit for detecting a property of the optical fiber transmission line by using parameters set in the digital equalization filter to compensate for the chromatic dispersion.
Dependencies are inferred from the claim text.