Abstract: An apparatus, e.g. an optical device, includes an optical transmitter and a mixer. The transmitter is configured to transmit a plurality of optical data channels that each include at least one spectral component at a same frequency. The mixer is configured to combine a first data channel with a second data channel. The combining is such that first and second optical channels output by the optical transmitter each include contributions from the first and second data channels at the same frequency.

Abstract: An apparatus and a method for accurately detecting Loss of Optical Power (LOS) by noise power cancellation effect and optical power is measured at two output ports of an athermal periodic filter, wherein one output port in the optical frequency domain, is aligned with the signal channels of an input WDM signal (on-grid port), whereas the second output port is aligned complementary to the first output port (off-grid port). In a preferred embodiment, the apparatus computes the ratio of the measured optical powers at the two output ports of the periodic filter, and comparing them to a threshold value that is determined from the overall common-mode rejection ratio (CMRR) of the detection apparatus. In an alternative embodiment, the apparatus additionally compares the optical power measured at the on-grid port to a threshold power that is determined from system design parameters.

Abstract: A method of optically equalizing a multi-level (amplitude or phase) optical signal through the effect of an optical equalizer wherein the optical equalizer (OEQ) is placed at either a transmission end or a receiver end of the optical communications link and a tap delay characteristic of the OEQ need not be determined by symbol spacing, rather it may advantageously be adjusted to desirably compensate non-linear mapping performed in the modulation process or simultaneous operation on a plurality of wavelength division multiplexed (WDM) channels.

Abstract: An apparatus and a method for accurately detecting Loss of Optical Power (LOS) by noise power cancellation effect and optical power is measured at two output ports of an athermal periodic filter, wherein one output port in the optical frequency domain, is aligned with the signal channels of an input WDM signal (on-grid port), whereas the second output port is aligned complementary to the first output port (off-grid port). In a preferred embodiment, the apparatus computes the ratio of the measured optical powers at the two output ports of the periodic filter, and comparing them to a threshold value that is determined from the overall common-mode rejection ratio (CMRR) of the detection apparatus. In an alternative embodiment, the apparatus additionally compares the optical power measured at the on-grid port to a threshold power that is determined from system design parameters.

Abstract: A method of optically equalizing a multi-level (amplitude or phase) optical signal through the effect of an optical equalizer wherein the optical equalizer (OEQ) is placed at either a transmission end or a receiver end of the optical communications link and a tap delay characteristic of the OEQ need not be determined by symbol spacing, rather it may advantageously be adjusted to desirably compensate non-linear mapping performed in the modulation process or simultaneous operation on a plurality of wavelength division multiplexed (WDM) channels.

Abstract: This invention provides a new architecture for a communication system between head-ends and end-users which expands bandwidth and reliability of the communication system. A mux-node receives communication signals from a head-end and forwards the received communication signals to one or more mini-fiber nodes. The connection to the head-end is via a small number of optical fibers and the connections to each of the mini-fiber nodes may be via one or more optical fibers that may provide full duplex communication. The head-end may communicate with the mux-node using digital or digital and analog signals. The mini-fiber nodes may combine the signals received from the head-end with loop-back signals used for local media access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and transmitted to the mux-node.

Abstract: This invention provides a new architecture for a communication system between head-ends and end-users which expands bandwidth and reliability of the communication system. A mux-node receives communication signals from a head-end and forwards the received communication signals to one or more mini-fiber nodes. The connection to the head-end is via a small number of optical fibers and the connections to each of the mini-fiber nodes may be via one or more optical fibers that may provide full duplex communication. The head-end may communicate with the mux-node using digital or digital and analog signals. The mini-fiber nodes may combine the signals received from the head-end with loop-back signals used for local media access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and transmitted to the mux-node.

Abstract: A system and method for increasing transmission distance and/or transmission data rates using tedons and an encoding scheme to reduce the number of ones in a data signal is described. The method for increasing transmission distance and transmission data rate of a fiber optical communications link using tedons comprises the steps of encoding a data signal to be transmitted using an encoding scheme that reduces a number of ones in said data signal, transmitting said encoded data signal over said fiber optical communications link, receiving said encoded data signal and decoding said encoded data signal.

Abstract: A multi-pump phase modulator apparatus and operating method uses only one phase modulator to eliminate SBS without degrading idler(s). The single phase modulator phase modulates multiple pump signals to form multiple phase modulated pump signals using a modulation signal having a modulation period. A delay apparatus delays a first wavelength group by the modulation period relative to other wavelength groups. A combiner combines the delayed first wavelength group with the other wavelength groups to form a combined modulated multiple pump signal. In one embodiment a multi-pump phase parametric apparatus comprises the multi-pump phase modulator apparatus combined with a parametric apparatus to generate an amplified input signal and one or more idlers. Other embodiments of the multi-pump phase conjugator apparatus are used as part of an Optical Switch, Sampler, Tributary Extractor, and Regenerator.

Abstract: Link robustness, chromatic dispersion and polarization mode dispersion (PMD) immunity can be improved in fiber optical system by using a method for receiving an optical double sideband signal over an optical fiber system, comprising the steps of splitting the received optical double sideband signal into an upper sideband signal and a lower sideband signal, photodetecting the upper sideband and the lower sideband, equalizing the photodetected upper sideband signal and the lower sideband signal, and combining the equalized upper sideband signal with the equalized lower sideband signal. While PMD compensation is envisioned as a major application, one may also use the method and system for chromatic dispersion compensation or dispersion slope compensation in high bit rate systems, i.e. using dispersion compensation fiber (DCF) for coarse compensation and diversity receiver with electrical equalizer for fine tuning.

Abstract: Methods and apparatus are provided for transmitting alternate-polarization phase-shift-keyed data. The output of a laser is modulated to optically encode electronic data using phase shift keying (PSK) to generate an optical signal. An alternate polarization PSK (APol-PSK) signal is generated by alternating the polarization of the optical signal using a modulator such that successive optical bits have substantially orthogonal polarizations.

Abstract: A method of multiple-band switching using a multi-pump fiber parametric switch is demonstrated. The switching architecture combines parametric band amplification, wavelength conversion and selective signal conjugation, enabled by temporal control of at least one pump of the multi-pump parametric device. The switching speed of the present invention is limited by the rise time of the controlled pump(s).

Abstract: The apparatus and method according to the present invention includes a semiconductor laser-modulator which is used to simultaneously generate optical pulses and encode data. The optical data output from the laser-modulator are soliton pulses in RZ format suitable for transmission in long distance optical communications.