Abstract: Systems may include one or more directly modulated laser (“DML”) optical transmitters to transmit optical signals carrying data to one or more optical receivers and include one or more filters designed to reduce the power in lower modulation levels. In various embodiments, the optical receiver includes an optical combiner to combine local oscillator light at a frequency, fLO with the optical data signal, an optical-electrical converter to downconvert the combined LO-optical signal to an electrical signal including four PAM4 frequencies, an electrical filter to attenuate the electrical power in the PAM4 frequencies by differing amounts, rectify and output the electrical signal. Systems may include extinction ratio management and thermal chirp compensation, and may include optical filters designed for chirp management with different laser parameters (? and k) and OMAs with PAM-M format in both optical and electrical domains and for use with quasi-coherent receivers (QCR) and DML transmitters.

Abstract: An asymmetric coherent receiver includes an optical front end configured to split a received optical signal into two paths, wherein the split received optical signal experiences a different optical transfer function in one of the two paths; two photodetectors each configured to detect power one of the split received optical signals in each of the two paths to obtain corresponding electrical signals; and circuitry configured to perform electrical domain extraction of information of each of the corresponding electrical signals from the two paths, wherein the different optical transfer function provides additional information utilized in optical field reconstruction via direct detection.

Abstract: Provided is a system, method, and device for non-invasive hemodynamic measurement of a subject. The method includes identifying vibrational pulses V1 and V2 and vibrations corresponding to cardiac mechanical motion from vibrational cardiography (VCG) data, the VCG data derived from a vibration signal acquired at the surface of the chest of the subject corresponding to cardiac-induced vibrations; determining a vibration feature from the vibration signal; and determining a hemodynamic measurement from the vibration feature.

Abstract: Methods in an optical receiver, for decoding a received M-level pulse-amplitude-modulated, PAM-M, optical signal. An example method comprises, for a first interval, decoding (510) the received PAM-M optical signal using a standard PAM-M decoder with M-1 thresholds, using first sampling times, to obtain a first set of decoded bits, and decoding (520) the received PAM-M optical signal using a duobinary decoder with 2M-2 thresholds, at second sampling times offset from the first sampling times, to obtain second set of decoded bits. The method further comprises calculating (530) first and second error metrics corresponding to the first and second sets of decoded bits, respectively, and selecting (540) the standard PAM-M decoder or the duobinary decoder for subsequent decoding of the received PAM-M optical signal, based on the first and second error metrics.

Abstract: An asymmetric coherent receiver includes an optical front end configured to split a received optical signal into two paths, wherein the split received optical signal experiences a different optical transfer function in one of the two paths; two photodetectors each configured to detect power one of the split received optical signals in each of the two paths to obtain corresponding electrical signals; and circuitry configured to perform electrical domain extraction of information of each of the corresponding electrical signals from the two paths, wherein the different optical transfer function provides additional information utilized in optical field reconstruction via direct detection.

Abstract: An optical modulation apparatus comprises first, second, and third optical modulators arranged so as to collectively modulate light coupled into a first optical input in all three dimensions of the three-dimensional Stokes vector space, to produce an optical output signal. The optical modulation apparatus further comprises a modulating circuit having a digital input configured to N generate first, second, and third modulating signals for driving the first, second, and third optical modulators so as to map digital data to an M-point optical constellation in the optical output signal. The points in the M-point optical constellation are distributed in the three-dimensional Stokes vector space such that the constellation figure of merit for the M-point optical constellation equals at least half of the maximum achievable constellation figure of merit for M points in the three-dimensional Stokes vector space.

Abstract: The disclosure relates to a transceiver operative to transmit and receive optical signals. The transceiver comprises a laser, a power splitter, a dual-polarization in-phase and quadrature modulator, DP-IQM, a first circulator (C1, C3), a second circulator (C2, C4), a first optical polarization controller, PC, a second optical polarization controller and a dual-polarization coherent receiver, DP-CRx. There is provided a system comprising a first transceiver and a second transceiver as described previously. The transceiver requires neither high speed DSP nor high resolution data converters to achieve 50 Gbaud DP-16 QAM, DP standing for dual polarization and QAM standing for quadrature amplitude modulation, yielding 400 Gb/s over 10 km below the 2.2×10?4 KP4 forward error correction (FEC) threshold.

Abstract: An optical modulation apparatus comprises first, second, and third optical modulators arranged so as to collectively modulate light coupled into a first optical input in all three dimensions of the three-dimensional Stokes vector space, to produce an optical output signal. The optical modulation apparatus further comprises a modulating circuit having a digital input configured to N generate first, second, and third modulating signals for driving the first, second, and third optical modulators so as to map digital data to an M-point optical constellation in the optical output signal. The points in the M-point optical constellation are distributed in the three-dimensional Stokes vector space such that the constellation figure of merit for the M-point optical constellation equals at least half of the maximum achievable constellation figure of merit for M points in the three-dimensional Stokes vector space.

Abstract: The disclosure relates to a transceiver operative to transmit and receive optical signals. The transceiver comprises a laser, a power splitter, a dual-polarization in-phase and quadrature modulator, DP-IQM, a first circulator (C1, C3), a second circulator (C2, C4), a first optical polarization controller, PC, a second optical polarization controller and a dual-polarization coherent receiver, DP-CRx. There is provided a system comprising a first transceiver and a second transceiver as described previously. The transceiver requires neither high speed DSP nor high resolution data converters to achieve 50 Gbaud DP-16 QAM, DP standing for dual polarization and QAM standing for quadrature amplitude modulation, yielding 400 Gb/s over 10 km below the 2.2×10?4 KP4 forward error correction (FEC) threshold.

Abstract: A semiconductor waveguide device includes a first semiconductor layer having a first surface, wherein the first surface comprises a first protrusion and a second protrusion collectively forming a first trench in the first semiconductor layer, a second semiconductor layer having a second surface opposing the first surface of the first semiconductor layer, and an insulator layer disposed between and in contact with the first surface and the second surface, wherein the first semiconductor layer, the second semiconductor layer, and the insulator layer form a semiconductor waveguide region, and wherein the first trench is configured to confine a mode of light beam propagation in the semiconductor waveguide region.

Abstract: Disclosed is a transmitter that modulates a single-wavelength laser signal with multi-level amplitude modulation on each of two polarizations, with an additional multi-level inter-polarization phase modulation. In an experimental setup, four-level amplitude modulation is used on each of the two polarizations, and four-phase inter-polarization phase modulation is used. Other numbers of levels may be used, in variations of the disclosed techniques and apparatus. Also disclosed is a corresponding receiver, which includes a DSP algorithm that recovers, simultaneously, the information on the multiple intensities imprinted by the transmitter on each polarization and the information from the multi-level inter-polarization phase modulation.

Abstract: In an optical communication system having flexible transceivers, a transmitter section of one of the flexible transceivers generates a modulated pilot signal whose amplitude or phase or both have been modulated according to a digital code. An optical signal is transmitted from the transmitter section to a receiver section of another of the flexible transceivers. The optical signal conveys data and the modulated pilot signal. The digital code encodes parameter information for the transmitter section and for the receiver section. The receiver section receives the modulated pilot signal, determines the digital code by demodulating the modulated pilot signal, and determines the parameter information from the digital code. The transmitter section and the receiver section adjust their configuration according to the parameter information. The receiver section, while configured according to the parameter information, processes received data or future received data.

Abstract: In an optical communication system having flexible transceivers, a transmitter section of one of the flexible transceivers generates a modulated pilot signal whose amplitude or phase or both have been modulated according to a digital code. An optical signal is transmitted from the transmitter section to a receiver section of another of the flexible transceivers. The optical signal conveys data and the modulated pilot signal. The digital code encodes parameter information for the transmitter section and for the receiver section. The receiver section receives the modulated pilot signal, determines the digital code by demodulating the modulated pilot signal, and determines the parameter information from the digital code. The transmitter section and the receiver section adjust their configuration according to the parameter information. The receiver section, while configured according to the parameter information, processes received data or future received data.

Abstract: Disclosed is a transmitter that modulates a single-wavelength laser signal with multi-level amplitude modulation on each of two polarizations, with an additional multi-level inter-polarization phase modulation. In an experimental setup, four-level amplitude modulation is used on each of the two polarizations, and four-phase inter-polarization phase modulation is used. Other numbers of levels may be used, in variations of the disclosed techniques and apparatus. Also disclosed is a corresponding receiver, which includes a DSP algorithm that recovers, simultaneously, the information on the multiple intensities imprinted by the transmitter on each polarization and the information from the multi-level inter-polarization phase modulation.

Abstract: A method and circuitry is provided to adapt VLSI built-in testing and self-testing to opto-electronic VLSI technology. This method facilitates the testing of lasers, laser drivers, receivers and photodiodes by extending the concepts of scan-chain testing and BER testing. The advantages of this method are most obvious for opto-electronic ASICs that have a large number of VCSELs arranged in a regular fashion, such as an array or a line. Quantitative and qualitative testing is performed with variations to the circuitry.