Abstract:
A distortion compensation circuit compensates for the distortions generated by the dispersion-slope of an optical component and the frequency chirp of an optical transmitter. The dispersion compensation circuitry can be utilized in the optical transmitter, the optical receiver and/or at some intermediate point in a fiber-optic network. One embodiment of the compensation circuit utilizes a primary electrical signal path that receives at least a portion of the input signal and a delay line; and a secondary signal path in parallel to the primary path that receives at least a portion of the input signal and including: an amplifier with an electrical current gain that is proportional to the dispersion-slope of the optical component, an optional RF attenuator, an optional delay line, a "squarer" circuit, and a "differentiator" circuit. Another embodiment of the disclosure performs simultaneous, and independent, compensation of second-order distortions generated by both the dispersion-slope of a first optical component and the dispersion of a second optical component. Other embodiments of the disclosure perform adaptive predistortion for compensation of distortions generated by the dispersion-slope of a first optical component and the dispersion of a second optical component to maintain optimum compensation even if the dispersion properties of the optical components change with time.
Abstract:
A method includes hosting a plurality of transmitter modules with a host module, where the host module includes common circuitry shared by the plurality of pluggable transmitter modules. An apparatus includes a host module; and a plurality of transmitter modules coupled to the host module, where the host module includes common circuitry shared by the plurality of pluggable transmitter modules.
Abstract:
A method includes: receiving a downstream optical signal propagating away from a head end and converting it into an electrical signal; dividing the downstream electrical signal into a downstream high portion and a downstream low portion; diplexing the downstream low portion with an upstream low portion; combining the upstream low portion and an upstream high portion; and transmitting the combined upstream portions as an upstream optical signal propagating toward a head end. An apparatus includes: an optical receiver; an electrical divider coupled to the optical receiver; an electrical diplexer coupled to the divider; an electrical combiner coupled to the diplexer; and an optical transmitter coupled to the combiner.
Abstract:
A method includes modulating a laser that is coupled to a fiber; modulating the laser with a member selected from the group consisting of low frequency thermal modulation or bias modulation to broaden a laser linewidth, increase an SBS threshold and reduce an UN; and modulating the laser with a predistorting modulation selected from the group consisting of phase modulation or amplitude modulation, the predistorting modulation being of equal magnitude but opposite phase as that produced in at least one member selected from the group consisting of the laser or the fiber as a result of the low frequency thermal modulation or bias modulation. An apparatus includes a laser; and a fiber coupled to the laser, wherein the laser is i) modulated ii) modulated with a member selected from the group consisting of low frequency thermal modulation or bias modulation to broaden a laser linewidth, increase an SBS threshold and reduce an UN and iii) modulated with a predistorting modulation selected from the group consisting of phase modulation or amplitude modulation, the predistorting modulation being of equal magnitude but opposite phase as that produced in at least one member selected from the group consisting of the laser or the fiber as a result of the low frequency thermal modulation or bias modulation.
Abstract:
A method includes modulating a laser that is coupled to a fiber; modulating the laser with a member selected from the group consisting of low frequency thermal modulation or bias modulation to broaden a laser linewidth, increase an SBS threshold and reduce an UN; and modulating the laser with a predistorting modulation selected from the group consisting of phase modulation or amplitude modulation, the predistorting modulation being of equal magnitude but opposite phase as that produced in at least one member selected from the group consisting of the laser or the fiber as a result of the low frequency thermal modulation or bias modulation. An apparatus includes a laser; and a fiber coupled to the laser, wherein the laser is i) modulated ii) modulated with a member selected from the group consisting of low frequency thermal modulation or bias modulation to broaden a laser linewidth, increase an SBS threshold and reduce an UN and iii) modulated with a predistorting modulation selected from the group consisting of phase modulation or amplitude modulation, the predistorting modulation being of equal magnitude but opposite phase as that produced in at least one member selected from the group consisting of the laser or the fiber as a result of the low frequency thermal modulation or bias modulation.
Abstract:
A method includes modulating a laser that is coupled to a fiber; modulating the laser with a member selected from the group consisting of low frequency thermal modulation or bias modulation to broaden a laser linewidth, increase an SBS threshold and reduce an UN; and modulating the laser with a predistorting modulation selected from the group consisting of phase modulation or amplitude modulation, the predistorting modulation being of equal magnitude but opposite phase as that produced in at least one member selected from the group consisting of the laser or the fiber as a result of the low frequency thermal modulation or bias modulation. An apparatus includes a laser; and a fiber coupled to the laser, wherein the laser is i) modulated ii) modulated with a member selected from the group consisting of low frequency thermal modulation or bias modulation to broaden a laser linewidth, increase an SBS threshold and reduce an UN and iii) modulated with a predistorting modulation selected from the group consisting of phase modulation or amplitude modulation, the predistorting modulation being of equal magnitude but opposite phase as that produced in at least one member selected from the group consisting of the laser or the fiber as a result of the low frequency thermal modulation or bias modulation.
Abstract:
Methods and apparatus are described for transmitting and receiving data. A method includes a process of transferring data over a coaxial network at a bandwidth above 1000 MHz, wherein the process of transferring data transfers the data between an optical node and a plurality of cable modems of a hybrid fiber-coaxial cable network. An apparatus includes a data transfer system which sends and receives data over a coaxial network at a bandwidth above 1000 MHz, wherein the data transfer system is located at an optical node of a hybrid fiber-coaxial cable network.
Abstract:
Methods, systems and devices are described for a chassis with repositionable plates. An apparatus, including a chassis having a frist module bay with a first plate mounting bracket, a second module bay with a second plate mounting bracket and a repositionable plate that is removably connectable to the first plate mounting bracket and removably connectable to said second plate mounting bracket.
Abstract:
Systems and methods are described for reverse digitized communications. A method includes: providing at least one optical fiber from at least one member selected from the group consisting of a headend and a hub, a minifibernode coupled to said at least one optical fiber, and an electrical conductor coupled to said minifibernode; transforming a forward optical signal from said at least one optical fiber to a forward analog electrical signal on said electrical conductor at said minifibernode; and transforming a reverse analog electrical signal on said electrical conductor to a reverse digital optical signal at said minifibernode. The systems and methods provide advantages because the need for muxnode units is eliminated, the cost of the node units is reduced, the amount of optical fiber is reduced and the reverse bandwidth is increased.
Abstract:
Methods, systems and devices are described relating to a chassis for front and back inserted modules. An apparatus includes a chassis including a first module bay and a second module bay, the first module bay and the second module bay together composing both a forward section and rearward section.