Abstract: Consistent with the present disclosure, data, in digital form, is received by a transmit node of an optical communication system, is processed and then output to drive a modulator. The modulator, in turn, modulates light at one of a plurality of wavelengths in accordance with the received data, forming a plurality of corresponding carriers. The plurality of wavelengths used for the plurality of carriers are spectrally spaced apart by a common, periodic fixed spacing. The plurality of carriers are optically combined with a fixed spacing combiner to form a superchannel. A plurality of superchannels are generated and then multiplexed together onto an optical communication path and transmitted to a receive node. Each superchannel includes a plurality of carriers, each spectrally separated by the same fixed spacing. The plurality of superchannels are spectrally separated by an amount corresponding to the fixed spacing of the plurality of carriers.

Abstract: An optical communication system with tunable sources may include a first optical source configured to supply a first optical signal having a first wavelength and a second optical source configured to supply a second optical signal having a second wavelength. An arrayed waveguide grating may include input waveguides having associated first and second passbands, the first passband being spectrally spaced from the second passband, the first passband including the first wavelength and the second passband including the second wavelength. A control circuit may selectively control the first and second optical sources to supply one of the first and second optical signals to one of the input waveguides, wherein, when the first optical signal is supplied to one of the plurality of input waveguides, the first optical signal is output from the output waveguide, and when the second optical signal is supplied to one of the plurality of input waveguides, the second optical signal is output from the output waveguide.

Abstract: Consistent with one example of the disclosed implementations, a photonic integrated circuit (PIC) may be provided that includes s group of lasers and an arrayed waveguide grating (AWG) disposed on a substrate. Each laser in the group may supply an optical signal, such that each optical signal has a different wavelength. Each laser may be tunable to at least two designated wavelengths, which are separated from one another by a free spectral range (FSR) of the AWG. As a result, the optical signals provided from each laser may be combined by the AWG, regardless of which designated wavelength the optical signals have. Accordingly, a PIC may be provided that has a relatively simple construction but can supply optical signals having tunable wavelengths.

Abstract: Pairs of distributed feedback (DFB) lasers are provided on a substrate. An arrayed waveguide grating (AWG) is also provided on the substrate having input waveguides, each of which being connected to a corresponding pair of DFB lasers. The wavelengths of optical signals supplied from each pair of DFB lasers may be spectrally spaced from one another by a free spectral range (FSR) of the AWG. By selecting either a first or second DFB laser in a pair and temperature tuning to adjust the wavelength, each pair of DFB lasers can supply optical signals at one of four wavelengths, pairs of which are spectrally spaced from one another by the FSR of the AWG. A widely tunable transmitter may thus be obtained.

Abstract: Consistent with the present disclosure, chromatic dispersion is introduced into an optical communication path including multiple segments or spans of dispersion shifted fiber (DSF). The chromatic dispersion generates phase mismatching between optical signals propagating along the optical communication path, i.e., the optical signals are decorrelated, such that mixing products are reduced inmagnitude, and the noise attributable to four wave mixing is correspondingly reduced.

Abstract: A Raman pump may include a dual output laser configured to output two optical signals; a delay interferometer configured to delay a first of the two optical signals to decorrelate the two optical signals from each other; and a combiner configured to combine the delayed first of the two optical signals and a second of the two optical signals to provide a Raman amplification signal.

Abstract: Consistent with the present disclosure, data, in digital form, is received by a transmit node of an optical communication system, and is then provided to a modulator that, in turn, modulates light, received from an optical source at one of a plurality of periodically and preferably minimally spaced wavelengths. The plurality of periodically spaced wavelengths or carriers are grouped together with minimal carrier spacing, to form a superchannel. The carrier spacing between adjacent carriers is determined by detecting a beat frequency of a combined optical signal that includes the outputs of two adjacent optical sources. The beat frequency corresponds to a frequency difference between the outputs of the adjacent carriers. This frequency difference should correspond to a desired carrier spacing between each of the plurality of carriers.

Abstract: A semiconductor optical amplifier module may include a beam splitter to split an optical signal into two polarization optical signals including a first polarization optical signal with a Transverse Magnetic (TM) polarization provided along a first path of two paths, and a second polarization optical signal with a Transverse Electric (TE) polarization provided along a second path of the two paths; a first rotator to rotate the TM polarization of the first polarization optical signal to TE polarization; a first semiconductor optical amplifier to amplify the rotated first polarization optical signal to output a first resultant optical signal; a second semiconductor optical amplifier to amplify the second polarization optical signal; and a second rotator to rotate the polarization of the amplified second polarization optical signal to output a second resultant optical signal; and a beam combiner to combine the first resultant optical signal and the second resultant optical signal.

Abstract: Methods and systems are disclosed including receiving, by circuitry of a node conforming to GMPLS protocol, a signal comprising at least one of an optical signal attribute indicative of parameters of a super-channel, the super-channel including a plurality of optical carriers, each of which having a corresponding one of a plurality of wavelengths and being modulated to carry a corresponding one of a plurality of data streams, the super-channel being provisioned in the optical network as one optical channel, wherein the optical signal attribute is one of: quantity of wavelengths of the super-channel, wavelength center frequency of the super-channel, wavelength modulation of the super-channel, wavelength baudrate of the super-channel, and wavelength FEC type of the super-channel. The node further receiving information indicative of frequency slices in use by the super-channel and calculating, using algorithms conforming to CSPF-TE protocol, a path of a second super-channel.

Abstract: The present disclosure provides a transmission system, apparatus and method to provide for variable channel spacing in multiplexed or combined optical signals for transmission over a network infrastructure. The channel spacing may be monitored and maintained at desired values in order to maximize the channel density under various conditions related to the network infrastructure. The individual carrier frequencies associated with each signal channel of the transmission system may be individually controlled to define the desired channel. The channel spacing may be altered to provide for higher channel densities increasing system capacity, or to provide for lower channel densities improving the overall reach of the transmission system. The channel spacing may be continuously monitored and maintained at desired values allowing for rapid and automated reconfiguration of the transmission system, which may result in maximized capacity and reduced costs.

Abstract: The present disclosure provides a system, apparatus and method to provide for monitoring of characteristics of optical signals, as part of wavelength division multiplexed signals for example, transmitted over a network infrastructure. The characteristics of each optical signal may be monitored and maintained at desired values in order to optimize system performance. A system including a coherent detector, as part of a coherent receiver for example, may be employed to associate each transmitted optical signal with a modulated source. Control signals generated by the system can then be provided to elements of the modulated source to control characteristics, such as optical power, optical frequency, and optical phase, for example, of the transmitted optical signal.

Abstract: A Raman pump may include a dual output laser configured to output two optical signals; a delay interferometer configured to delay a first of the two optical signals to decorrelate the two optical signals from each other; and a combiner configured to combine the delayed first of the two optical signals and a second of the two optical signals to provide a Raman amplification signal.

Abstract: A semiconductor optical amplifier module may include a beam splitter to split an optical signal into two polarization optical signals including a first polarization optical signal with a Transverse Magnetic (TM) polarization provided along a first path of two paths, and a second polarization optical signal with a Transverse Electric (TE) polarization provided along a second path of the two paths; a first rotator to rotate the TM polarization of the first polarization optical signal to TE polarization; a first semiconductor optical amplifier to amplify the rotated first polarization optical signal to output a first resultant optical signal; a second semiconductor optical amplifier to amplify the second polarization optical signal; and a second rotator to rotate the polarization of the amplified second polarization optical signal to output a second resultant optical signal; and a beam combiner to combine the first resultant optical signal and the second resultant optical signal.

Abstract: Methods and systems are disclosed including receiving, by circuitry of a node conforming to GMPLS protocol, a signal comprising at least one of an optical signal attribute indicative of parameters of a super-channel, the super-channel including a plurality of optical carriers, each of which having a corresponding one of a plurality of wavelengths and being modulated to carry a corresponding one of a plurality of data streams, the super-channel being provisioned in the optical network as one optical channel, wherein the optical signal attribute is one of: quantity of wavelengths of the super-channel, wavelength center frequency of the super-channel, wavelength modulation of the super-channel, wavelength baudrate of the super-channel, and wavelength FEC type of the super-channel. The node further receiving information indicative of frequency slices in use by the super-channel and calculating, using algorithms conforming to CSPF-TE protocol, a path of a second super-channel.

Abstract: Consistent with one example of the disclosed implementations, a photonic integrated circuit (PIC) may be provided that includes s group of lasers and an arrayed waveguide grating (AWG) disposed on a substrate. Each laser in the group may supply an optical signal, such that each optical signal has a different wavelength. Each laser may be tunable to at least two designated wavelengths, which are separated from one another by a free spectral range (FSR) of the AWG. As a result, the optical signals provided from each laser may be combined by the AWG, regardless of which designated wavelength the optical signals have. Accordingly, a PIC may be provided that has a relatively simple construction but can supply optical signals having tunable wavelengths.

Abstract: Pairs of distributed feedback (DFB) lasers are provided on a substrate. An arrayed waveguide grating (AWG) is also provided on the substrate having input waveguides, each of which being connected to a corresponding pair of DFB lasers. The wavelengths of optical signals supplied from each pair of DFB lasers may be spectrally spaced from one another by a free spectral range (FSR) of the AWG. By selecting either a first or second DFB laser in a pair and temperature tuning to adjust the wavelength, each pair of DFB lasers can supply optical signals at one of four wavelengths, pairs of which are spectrally spaced from one another by the FSR of the AWG. A widely tunable transmitter may thus be obtained.

Abstract: Consistent with the present disclosure, chromatic dispersion is introduced into an optical communication path including multiple segments or spans of dispersion shifted fiber (DSF). The chromatic dispersion generates phase mismatching between optical signals propagating along the optical communication path, i.e., the optical signals are decorrelated, such that mixing products are reduced inmagnitude, and the noise attributable to four wave mixing is correspondingly reduced.

Abstract: Consistent with the present disclosure, data, in digital form, is received by a transmit node of an optical communication system, is processed and then output to drive a modulator. The modulator, in turn, modulates light at one of a plurality of wavelengths in accordance with the received data, forming a plurality of corresponding carriers. The plurality of wavelengths used for the plurality of carriers are spectrally spaced apart by a common, periodic fixed spacing. The plurality of carriers are optically combined with a fixed spacing combiner to form a superchannel. A plurality of superchannels are generated and then multiplexed together onto an optical communication path and transmitted to a receive node. Each superchannel includes a plurality of carriers, each spectrally separated by the same fixed spacing. The plurality of superchannels are spectrally separated by an amount corresponding to the fixed spacing of the plurality of carriers.

Abstract: Consistent with the present disclosure, data, in digital form, is received by a transmit node of an optical communication system, and is then provided to a modulator that, in turn, modulates light, received from an optical source at one of a plurality of periodically and preferably minimally spaced wavelengths. The plurality of periodically spaced wavelengths or carriers are grouped together with minimal carrier spacing, to form a superchannel. The carrier spacing between adjacent carriers is determined by detecting a beat frequency of a combined optical signal that includes the outputs of two adjacent optical sources. The beat frequency corresponds to a frequency difference between the outputs of the adjacent carriers. This frequency difference should correspond to a desired carrier spacing between each of the plurality of carriers.

Abstract: The present disclosure provides a transmission system, apparatus and method to provide for variable channel spacing in multiplexed or combined optical signals for transmission over a network infrastructure. The channel spacing may be monitored and maintained at desired values in order to maximize the channel density under various conditions related to the network infrastructure. The individual carrier frequencies associated with each signal channel of the transmission system may be individually controlled to define the desired channel. The channel spacing may be altered to provide for higher channel densities increasing system capacity, or to provide for lower channel densities improving the overall reach of the transmission system. The channel spacing may be continuously monitored and maintained at desired values allowing for rapid and automated reconfiguration of the transmission system, which may result in maximized capacity and reduced costs.