摘要:
It is disclosed an optical coherent receiver for an optical communication network. The optical coherent receiver is configured to receive a modulated optical signal and to process it for generating an in-phase component and a quadrature component. The optical coherent receiver comprises a power adjuster in turn comprising a multiplying unit and a retroactively connected digital circuit. The multiplying unit is configured to multiply the in-phase and quadrature components by in-phase and quadrature gains, respectively, thereby providing power-adjusted in-phase and quadrature components. The digital circuit is configured to compute: a common gain indicative of a sum of the powers of the power-adjusted in-phase and quadrature components; a differential gain indicative of a difference between the powers of the power-adjusted in-phase and quadrature components; and the in-phase and quadrature gains as a product and a ratio, respectively, between the common gain and the differential gain.
摘要:
A method of determining a chromatic dispersion of an optical channel is proposed. The method comprises different steps. An optical signal that is transmitted via an optical transmission channel is received. The optical signal is sampled , such that a first set of sampling data is obtained. For the first set of sampling data, a frequency analysis via a spectral transform is carried out, such that a frequency component at a first frequency and frequency component at a second frequency is determined. The second frequency is chosen such that it differs from the first frequency by the symbol rate of the optical signal. Furthermore, a phase shift of a spectral density is determined, wherein the spectral density is based on the determined frequency components at the first frequency. Finally, a chromatic dispersion value of the optical transmission channel is determined based on the determined phase shift.
摘要:
It is disclosed a digital filter configured to receive a sequence of samples, in particular to receive in parallel N samples per clock cycle, and to calculate a sum of L consecutive samples of the sequence. The digital filter comprises an integrating circuit and a differentiating circuit. The integrating circuit calculates two integrals of the sequence, up to the first sample and up to the last sample of the L consecutive samples, respectively. The differentiating circuit calculates the sum as a difference between the two integrals. The integrating circuit comprises: a cumulative sum module calculating a cumulative sum of the last sample and preceding samples received within the current clock cycle; a register storing a delayed integral calculated on samples received before the current clock cycle; and an addition module calculating the integral of the sequence up to the last sample by adding the cumulative sum and the delayed integral.
摘要:
It is disclosed a coherent optical receiver configured to receive a modulated optical signal and to generate an in-phase component and a quadrature component. The optical coherent receiver comprises a phase skew compensator in turn comprising a first digital circuit and a second digital circuit retroactively connected between an output and a control input of the first digital circuit. The first digital circuit provides a compensated in-phase component as a sum of the in-phase component multiplied by a first gain and the quadrature component multiplied by a second gain, and a compensated quadrature component as a sum of the in-phase component multiplied by a third gain and the quadrature component multiplied by a fourth gain. The second digital circuit computes the first, second, third and fourth gain as functions of an estimated cross-correlation between the compensated in-phase component and the compensated quadrature component.