Abstract: Methods and devices are provided to facilitate production of optical signals that exhibit reduced crosstalk noise and intersymbol interference. In some configurations, a multi-stage optical interleaver, including a first and a second optical interleaver, is used to process a first and a second set of input optical channels. The composite optical output of the multi-stage interleaver includes the first set of optical channels and the second set of optical channels, where each of the first and second set of input optical channels is processed once by the first optical interleaver and once by the second optical interleaver. As such, the first and second sets of input optical channels are each filtered twice using only two optical interleavers.

Abstract: The disclosure relates to a method for optical frequency-locked multi-carrier generation based on one directly-modulated laser (DML) and one phase modulator (PM) in cascade driven by sinusoidal waveform (at the same or different frequency). When the DML and PM is driven by the same frequency RF signal at 12.5 GHz, adopting this method, 16 optical subcarriers with 12.5-GHz frequency spacing are generated with power difference less than 3 dB. When the DML and PM is driven by the different frequency with DML at 12.5 Ghz and PM at 25 GHz, over 24 optical subcarriers are generated with 12.5-GHz frequency spacing and amplitude fluctuation less than 3 dB. The number of the generated optical subcarriers can be further increased when the driving power for the DML is increased.

Abstract: An optical transmitter determines the transfer function in the reference-based pre-equalization for applying to an optically modulated signal at the transmitter. The determined pre-equalization transfer function is made robust to linewidth inaccuracy of the optical source by performing phase correction during the calculation of the pre-equalization transfer function. The phase correction includes averaging a number of consecutive received phase samples. The determined pre-equalization transfer function is applied to modulated signals prior to the transmission over an optical medium.

Abstract: An optical transmitter transmits a dual polarization optical Nyquist frequency domain multiplexed signal. The signal includes a first polarization component and a second polarization component. Each component comprises multiple subchannels, possibly having different subchannel bandwidths and different modulation schemes. An optical receiver receives the signal and recovers transmitted data.

Abstract: An optical transmitter comprises: first and second sets of optical in-phase and quadrature modulators; an integrable tunable laser assembly; a first polarization beam splitter that is configured to divide the continuous-waveform optical signal into a x-polarized tributary and a y-polarized tributary, each of the x-polarized tributary and the y-polarized tributary is modulated by one of the first and second sets of optical in-phase and quadrature modulators in accordance with the two respective input signals; a second polarization beam splitter that is configured to combine the modulated x-polarized tributary and the modulated y-polarized tributary into one optical signal; and an optical modulator that is configured to modulate the combined optical signal using a driving voltage, wherein the driving voltage has a bias point that is reduced by a predefined offset from a predefined reference voltage level.

Abstract: A heterodyne optical signal detector and method performed thereby, the signal detector including an optical signal spectrum shaper operable to modify the shape of the frequency spectrum of a received optical signal, a laser local oscillator (LO), and polarization beam splitters (PBSs) to divide the signal and the LO into orthogonal components, waveguides in which intermediate frequency (IF) signals are formed, balanced photodetectors (BPDs) arranged to receive the IF signals and operable to convert the IF signals into electric signals, and analog to digital converters (ADCs) that digitize the electric signals.

Abstract: A simplified coherent receiver based on heterodyne detection with only two balanced photo detectors (PD) and two analog-to-digital converters (ADC) is disclosed. The polarization diversity hybrid can be simplified relative to the conventional one. The detected intermediate frequency signals are first down converted to baseband with I/Q separation.

Abstract: An optical signal transmitting system, comprising: an optical transmitter including one or more input terminals and an output terminal; and a temporal polarization interleaver including an input terminal and an output terminal, wherein the output terminal of the optical transmitter is communicatively coupled to the input terminal of the temporal polarization interleaver, wherein: the optical transmitter is configured to receive one or more input signals through its one or more input terminals, generate an output signal using the one or more input signals, the output signal including a x-polarized tributary and a y-polarized tributary that is pulse-to-pulse aligned with the x-polarized tributary, and transmit the output signal to the temporal polarization interleaver; and the temporal polarization interleaver is configured to receive the output signal from the optical transmitter and cause a predefined phase delay to one of the x-polarized tributary and the y-polarized tributary.

Abstract: Methods and devices are provided to facilitate production of optical signals that exhibit reduced crosstalk noise and intersymbol interference. In some configurations, a multi-stage optical interleaver, including a first and a second optical interleaver, is used to process a first and a second set of input optical channels. The composite optical output of the multi-stage interleaver includes the first set of optical channels and the second set of optical channels, where each of the first and second set of input optical channels is processed once by the first optical interleaver and once by the second optical interleaver. As such, the first and second sets of input optical channels are each filtered twice using only two optical interleavers.