A millimeter-wave communication device includes a coupler, Radio-Frequency (RF) circuitry and a composite right/left-handed metamaterial assembly. The coupler is configured to connect to a waveguide, the waveguide being transmissive at millimeter-wave frequencies and having a given dispersion characteristic over a predefined band of the millimeter-wave frequencies. The RF circuitry is configured to transmit a millimeter-wave signal into the waveguide via the coupler, or to receive a millimeter-wave signal from the waveguide via the coupler, and to process the millimeter-wave signal. The composite right/left-handed metamaterial assembly is formed to apply to the millimeter-wave signal, or to an Intermediate-Frequency (IF) signal corresponding to the millimeter-wave signal, a dispersion compensation that compensates for at least part of the dispersion characteristic of the waveguide over the predefined band.

This disclosure describes devices and methods related to multiplexing optical datasignals. A method may be disclosed. The method may comprise receiving, by a dense wave division multiplexer (DWDM), one or more optical data signals. The method may comprise combining, by the DWDM, the one or more optical data signals. The method may comprise outputting, by the DWDM, the combined one or more optical data signals to a first circulator. The method may also comprise combining, by the WDM, the second optical data signal and one or more third signals, and outputting an egress optical data signal to an optical switch. The method may also comprise outputting, by the optical switch, the egress optical data signal on a primary fiber.

A binary encoder includes an input configured to receive a binary signal, an encoding processor configured to compute a plurality of different variations of the binary signal, combine each of the different variations with a different redundancy sequence to create a plurality of optional output binary sequences, and select one of the optional output binary sequences according to a binary digit prevalence, and an output configured to output the selected binary sequence. A decoder configured to identify a redundancy sequence of a received binary signal to select a transformation function according to the redundancy sequence and to convert the binary signal according to the transformation function.

[Problem] A signal distortion generated when a multi-level modulated optical signal is transmitted through an optical transmission path where optical amplifiers are scattered is suppressed and transmission quality is improved.

[Solution] An optical transmission system 20 includes Tx 21a to Tx 21n configured to transmit a multi-level modulated optical signal 32 to an optical fiber 25, optical amplifiers 26a to 26f configured to amplify the optical signal 32 transmitted through the optical fiber 25, the optical amplifiers 26a to 26f being scattered on the optical fiber 25, and Rx 24a to Rx 24n configured to receive the amplified optical signal 32 via the optical fiber 25. A pre-dispersion compensation unit 27 of each of the Tx 21a to Tx 21n performs pre-dispersion compensation on the transmitted optical signal 32, based on a pre-dispersion compensation ratio for determining a percentage of dispersion compensation to be performed in advance on a wavelength dispersion to be accumulated in the optical fiber 25, with respect to the dispersion compensation to narrow a bandwidth to be widened by the wavelength dispersion during transmission of the optical signal 32 through the optical fiber 25.

Described herein are systems and methods that perform coarse chromatic dispersion (CD) compensation by applying precomputed coarse front-end equalizer (FEE) tap weights to a receiver based on an assumed propagation distance. After a waiting period, the FEE tap weights are applied, and it is determined whether the FEE tap weights cause a decision-directed tracking of channel rotations to satisfy a stability metric. In response to the stability metric not being satisfied, the assumed propagation distance is adjusted and used to obtain updated FEE tap weights. Conversely, if the stability metric is satisfied, a fine CD compensation is performed that comprises maintaining the updated FEE tap weights; performing an iterative least-mean-squared (LMS) error adaption to adjust Back-End Equalizer (BEE) tap weights and obtain updated BEE tap weights; and using the updated BEE tap weights to adjust the FEE tap weights to, ultimately, have the BEE output an equalized data bit stream.

An optical dispersion compensator integrated with a silicon photonics system including a first phase-shifter coupled to a second phase-shifter in parallel on the silicon substrate characterized in an athermal condition. The dispersion compensator further includes a third phase-shifter on the silicon substrate to the first phase-shifter and the second phase-shifter through two 2×2 splitters to form an optical loop. A second entry port of a first 2×2 splitter is for coupling with an input fiber and a second exit port of a second 2×2 splitter is for coupling with an output fiber. The optical loop is characterized by a total phase delay tunable via each of the first phase-shifter, the second phase-shifter, and the third phase-shifter such that a normal dispersion (>0) at a certain wavelength in the input fiber is substantially compensated and independent of temperature.

A frequency chirp correction method for the photonic time-stretch system comprises acquiring the stretching signal, i.e. acquiring the time-domain data after the time-domain stretching. First, the time-domain data of the stretching signal is Fourier transformed to obtain the spectral distribution. The spectral distribution is then convoluted with the first frequency-domain correction factor, and then multiplied with the second frequency-domain correction factor to obtain the modified frequency spectrum. Finally, the modified frequency spectrum is performed by the inverse Fourier transform to obtain the time-domain signal after the frequency chirp correction.

A band division timing adjustment unit aligns timings of a plurality of signals, which are generated by dividing a received signal according to a plurality of frequency bands, in a time domain and combines the plurality of signals for which the timings have been aligned. A chromatic dispersion compensation unit compensates chromatic dispersion of an output signal of the band division timing adjustment unit for each of the plurality of frequency bands.

A receiver is configured to calculate a representation of a received signal conveying symbols at a frequency f.sub.S, the representation comprising non-zero components at frequencies of magnitudes exceeding f.sub.S/2. The receiver calculates a first term comprising a function of a phase difference between the representation at a first pair of frequencies separated by a gap and comprised within a first band of width 2 centered at f.sub.S/2, and a second term comprising a function of a phase difference between the representation at a second pair of frequencies separated by the gap and comprised within a second band of width 2 centered at f.sub.S/2, wherein <2, and wherein the higher frequency of the first pair and the higher frequency of the second pair are separated by the frequency f.sub.S. An estimate of chromatic dispersion in the received signal is calculated based on the first term and the second term.

An optical fiber transmission system and method for using the system are provided. The system may include a span of transmission fiber for transmitting light signals through the optical fiber transmission system. The system may include a dispersion compensating module coupled to the span of transmission fiber. The system may include a switchable module including a set of selectable light signal paths, the set of selectable light signal paths including at least one path through a dispersion compensating element. The system may include a processor coupled to the switchable module for selectively monitoring the set of selectable light signal paths, where the processor is further configured to derive a metric based on the set of selectable light signal paths for controlling the dispersion compensating module.