Abstract: An apparatus comprising means for: causing illumination of different areas of a sample with an optical frequency imaging beam at different positions at different times, wherein adjacent positions are configured to cause the corresponding areas to at least partially overlap; receiving signals indicative of back-scattering of the optical frequency imaging beam from the sample at the different times; and processing the received signals to obtain an image of the sample, wherein processing the received signals compensates for phase variations between the different positions at the different times using a matched filter derived from a scattering model of the sample.

Abstract: The present disclosure is directed to imaging LiDARs monolithic integration of focal plane switch array LiDARS with CMOS electronics. The CMOS wafer contains electronic circuits needed to control the focal plane array, e.g., digital addressing circuits and MEMS drivers, as well as circuits to amplify and process the detected signals, e.g., trans-impedance amplifiers (TIA), multi-stage amplifiers, analog-to-digital converters (ADC), digital signal processing (DSP), and circuits to communicate with external systems. Methods of use are also provided.

Abstract: An apparatus comprising means for: causing illumination of different areas of a sample with an optical frequency imaging beam at different positions at different times, wherein adjacent positions are configured to cause the corresponding areas to at least partially overlap;receiving signals indicative of back-scattering of the optical frequency imaging beam from the sample at the different times; and processing the received signals to obtain an image of the sample, wherein processing the received signals compensates for phase variations between the different positions at the different times using a matched filter derived from a scattering model of the sample.

Abstract: Various example embodiments for supporting forward error correction (FEC) in a communication system are presented. Various example embodiments for supporting FEC in a communication system may include selection of a FEC setting (e.g., an amount of puncturing and/or shortening of a FEC code, a FEC code, or the like) for a communication channel from a transmitter to a receiver based on channel characteristic information of the communication channel from the transmitter to the receiver (e.g., transfer function information, channel loss information, noise characteristic information, error information (e.g., bit error rate, error modeling, or the like), or the like). Various example embodiments for supporting FEC in a communication system, based on selection of a FEC setting for a communication channel based on channel characteristic information of the communication channel, may be applied within various types of communication systems, including various types of wired and/or wireless communication systems.

Abstract: The present invention aims to provide a cyclosporine external preparation showing improved transdermal absorbability of cyclosporine. The present invention provides an external preparation containing cyclosporine and a ketone.

Abstract: Pilot-aided digital coherent reception of high-order QAM signal detection using a continuous short pilot preamble and subsequent pilot symbols that are periodically distributed with payload data resulting in low-complexity and fast-convergence signal detection for continuous mode coherent reception of high-order QAM signals. A digital signal processor is configured to demodulate a transmitted data stream from digital stream of measurements of light mixtures produced in a receiver for coherent optical communications in response to receiving modulated optical carriers. The digital signal processor includes one circuit stage for providing corrections to the digital stream to compensate first effects on the light mixtures due to a frequency shift of a local optical oscillator of the receiver and another circuit stage for correcting the digital stream to compensate for second effects on the light mixtures due to polarization dependent channel modification of the modulated optical carriers.

Abstract: A coherent optical receiver in which the channel equalizer and the clock-recovery circuit are connected in a nested-loop configuration, wherein the channel estimate generated by the equalizer is used to adjust the phase of the clock signal generated by the clock-recovery circuit. The channel equalizer can be implemented using a bank of time-domain or frequency-domain FIR filters. In an example embodiment, the clock-recovery circuit is configured to track the phase rotation corresponding to the equalized signals in a frequency-dependent manner; track the phase rotation in the channel equalizer either in a frequency-dependent manner or based on the mean signal delay therein; and adjust the phase of the clock signal based on an effective difference between these two phase rotations. The clock-recovery circuit enhances the clock tone by applying a Fourier transform to the squared absolute values of the equalized signals outputted by the channel equalizer.

Abstract: A coherent optical receiver in which the channel equalizer and the clock-recovery circuit are connected in a nested-loop configuration, wherein the channel estimate generated by the equalizer is used to adjust the phase of the clock signal generated by the clock-recovery circuit. The channel equalizer can be implemented using a bank of time-domain or frequency-domain FIR filters. In an example embodiment, the clock-recovery circuit is configured to track the phase rotation corresponding to the equalized signals in a frequency-dependent manner; track the phase rotation in the channel equalizer either in a frequency-dependent manner or based on the mean signal delay therein; and adjust the phase of the clock signal based on an effective difference between these two phase rotations. The clock-recovery circuit enhances the clock tone by applying a Fourier transform to the squared absolute values of the equalized signals outputted by the channel equalizer.

Abstract: Pilot-aided digital coherent reception of high-order QAM signal detection using a continuous short pilot preamble and subsequent pilot symbols that are periodically distributed with payload data resulting in low-complexity and fast-convergence signal detection for continuous mode coherent reception of high-order QAM signals. A digital signal processor is configured to demodulate a transmitted data stream from digital stream of measurements of light mixtures produced in a receiver for coherent optical communications in response to receiving modulated optical carriers. The digital signal processor includes one circuit stage for providing corrections to the digital stream to compensate first effects on the light mixtures due to a frequency shift of a local optical oscillator of the receiver and another circuit stage for correcting the digital stream to compensate for second effects on the light mixtures due to polarization dependent channel modification of the modulated optical carriers.

Abstract: We disclose a lidar system that includes a modulator-based probe-light generator and a coherent optical receiver. The probe-light generator uses tunable carrier-suppressed single-sideband modulation to generate frequency-chirped optical pulses for the optical-probe beam directed at the target. The coherent optical receiver uses a homodyne detection scheme in which a split portion of the optical-probe beam is used as an optical local oscillator signal for detecting a corresponding optical beam reflected by the target. The resulting electrical RF signals generated by the receiver can be processed, e.g., using a disclosed signal-processing method, to determine one or both of the distance to the target and the velocity of the target.

Abstract: An apparatus includes an electronic digital signal processor having electrical inputs for receiving a first sequence of measurements of values of a transmitted modulated optical carrier received in a coherent optical receiver and having electrical outputs for a stream of determined transmitted data values demodulated therein from the first sequence. The electronic digital signal processor has first circuitry to determine phase offsets of received pilot values from the first sequence. Additionally, the electronic digital signal processor has second circuitry to correct phase offsets of received ones of the data values from the determined phases of pilot values and data values being temporally interleaved in the transmitted modulated optical carrier. A system and a method are also included.

Abstract: A coherent optical receiver having an analog electrical circuit connected to combine the outputs of multiple photodetectors to generate an electrical output signal from which the data encoded in a received modulated optical signal can be recovered in a robust and straightforward manner. In an example embodiment, the analog electrical circuit includes one or more transimpedance amplifiers connected between the photodetectors and the receiver's output port. The coherent optical receiver may include a dual-polarization optical hybrid coupled to eight photodiodes to enable polarization-insensitive detection of the received modulated optical signal. The signal processing implemented in the analog electrical circuit advantageously enables the use of relatively inexpensive local-oscillator sources that may have relaxed specifications with respect to linewidth and wavelength stability.

Abstract: An apparatus includes an electronic digital signal processor having electrical inputs for receiving a first sequence of measurements of values of a transmitted modulated optical carrier received in a coherent optical receiver and having electrical outputs for a stream of determined transmitted data values demodulated therein from the first sequence. The electronic digital signal processor has first circuitry to determine phase offsets of received pilot values from the first sequence. Additionally, the electronic digital signal processor has second circuitry to correct phase offsets of received ones of the data values from the determined phases of pilot values and data values being temporally interleaved in the transmitted modulated optical carrier. A system and a method are also included.

Abstract: An apparatus includes an optical receiver that includes a processor. The receiver is configured to direct a digital-electrical representation of a received symbol value of a pulse-amplitude modulated signal to a frequency-domain processing path of the processor and to a time-domain processing path of the processor. The processor is configured to compute, in the frequency-domain processing path, a first product of the received symbol value and a first coefficient, and to compute a second product of the received symbol value and a second coefficient. The processor is further configured to compute, in the time-domain processing path, an estimated error metric based on the first and second products, and to determine an updated first coefficient and an updated second coefficient based on said error metric. The processor is further configured to equalize a subsequent received symbol using the updated coefficients.

Abstract: The present invention is intended to provide a cyclosporine external preparation that improves transdermal absorption of cyclosporine. The present invention provides an external preparation containing cyclosporine, ethanol, and a fatty acid monoester.

Abstract: We disclose an optical add-drop multiplexer that can apply different routing operations to different subcarriers of a data frame. In an example embodiment, the digital signal processor (DSP) of the optical add-drop multiplexer carries out subcarrier-specific add, drop, and pass-through operations in the electrical frequency domain, which enables the DSP to only partially unwrap the pass-through subcarriers, thereby at least partially avoiding some of the more processing-power-hungry DSP operations and reducing the sub-wavelength routing latency accordingly. Also disclosed is an example data-frame structure that can be used to provide subcarrier-specific routing instructions to the optical add-drop multiplexer.

Abstract: A coherent optical receiver that is capable of obtaining separate estimates of the I/Q phase imbalances caused by the front-end circuits of the receiver and transmitter. In an example embodiment, the receiver's I/Q imbalance is estimated using equalization coefficients of a first digital equalizer located upstream from the carrier-recovery module in the train of digital-signal processing implemented at the receiver, whereas the transmitter's I/Q imbalance is estimated using equalization coefficients of a second digital equalizer located downstream from the carrier-recovery module. The receiver DSP can then use the first estimate to carry out signal processing that reduces adverse effects of the receiver's I/Q imbalance on data recovery at the receiver. The receiver can also provide the estimate of the transmitter's I/Q phase imbalance to the transmitter, which can then perform digital signal pre-distortion directed at compensating that I/Q imbalance at the transmitter.

Abstract: We disclose a lidar system that includes a modulator-based probe-light generator and a coherent optical receiver. The probe-light generator uses tunable carrier-suppressed single-sideband modulation to generate frequency-chirped optical pulses for the optical-probe beam directed at the target. The coherent optical receiver uses a homodyne detection scheme in which a split portion of the optical-probe beam is used as an optical local oscillator signal for detecting a corresponding optical beam reflected by the target. The resulting electrical RF signals generated by the receiver can be processed, e.g., using a disclosed signal-processing method, to determine one or both of the distance to the target and the velocity of the target.

Abstract: We disclose an optical add-drop multiplexer that can apply different routing operations to different subcarriers of a data frame. In an example embodiment, the digital signal processor (DSP) of the optical add-drop multiplexer carries out subcarrier-specific add, drop, and pass-through operations in the electrical frequency domain, which enables the DSP to only partially unwrap the pass-through subcarriers, thereby at least partially avoiding some of the more processing-power-hungry DSP operations and reducing the sub-wavelength routing latency accordingly. Also disclosed is an example data-frame structure that can be used to provide subcarrier-specific routing instructions to the optical add-drop multiplexer.

Abstract: An optical receiver includes an equalizer to generate a plurality of equalization coefficients corresponding to a plurality of frequencies of an optical signal received by the optical receiver. The equalizer zeroes out a first subset of the equalization coefficients corresponding to a first subset of the plurality of frequency components and applies a second subset of non-zero equalization coefficients to the first signal. The optical receiver may also include a chromatic dispersion compensator to generate inverse chromatic dispersion coefficients corresponding to the plurality of frequency components, and to zero out a first subset of the inverse chromatic dispersion coefficients corresponding to the first subset of the plurality of frequency components and further to apply a second subset of non-zero inverse chromatic dispersion coefficients to a second optical signal.