Abstract: The technology described in this document can be used to implement beam steering in optical systems and photonic devices, to provide a nonmechanical beam steering system for projecting optical energy and controlling the direction of the optical energy using a collection of devices and components that are fixed in position to selectively direct light from an array of different optical emitters at different locations.

Abstract: Microwave photonic devices use light to carry and process microwave signals over a photonic link. Light can be used as a stimulus to microwave devices that directly control microwave signals. Previous optically controlled devices suffer from large footprint, high optical power level required for switching, lack of scalability and complex integration requirements, restricting their implementation in practical microwave systems. Disclosed are monolithic optically reconfigurable integrated microwave switches (MORIMSs) built on a CMOS compatible silicon photonic chip. The disclosed scalable micrometer-scale switches provide higher switching efficiency and operate using optical power that is orders of magnitude lower than previous devices. The disclosed devices and techniques provide examples of silicon photonic platforms integrating microwave circuitry.

Abstract: Various technologies described herein pertain to variable gain amplification for a sensor application. A multistage variable gain amplifier system provides variable gain amplification of an input signal. The multistage variable gain amplifier system includes a plurality of amplification stages. The multistage variable gain amplifier system further includes a power detector configured to detect a power level of an input signal received by the multistage variable gain amplifier system. The multistage variable gain amplifier system also includes a controller configured to control the amplification stages based on the power level of the input signal. The multistage variable gain amplifier system can output an output signal such that the amplification stages are controlled to adjust a gain applied to the input signal by the multistage variable gain amplifier system to output the output signal.

Abstract: Various technologies described herein pertain to a time of flight lidar sensor system that uses a coherent detection scheme. The lidar sensor system includes a laser source, a semiconductor optical amplifier, a combiner, and a balanced detector. The laser source emits an input optical signal. The semiconductor optical amplifier receives a first portion of the input optical signal and outputs a modulated optical signal (amplified and modulated). The combiner receives a second portion of the input optical signal and a returned optical signal received responsive to transmission of at least a portion of the modulated optical signal. The combiner coherently mixes the second portion of the input optical signal with the returned optical signal and outputs mixed optical signals. The balanced detector detects the mixed optical signals and generates an output signal (e.g., a differential photocurrent), which can be used to detect a distance to a target.

Abstract: A photonic synthesizer includes a multifrequency optical source to produce a signal of interest from a pair of lasers, which may be self-injection locked chip lasers. The signal is referenced to a high frequency clock using a photonic mixer/divider based on an electro-optical modulator and a relatively slow photodiode. The electro-optical modulator produces optical harmonics from the beams from the pair of lasers, where one harmonic from the first laser beam and one harmonic from the second laser beam beat on the photodiode. A phase locked control signal is generated for controlling the output frequency of one or both of the two lasers. The output signal of the photonic synthesizer is generated using a relatively fast photodiode based on a difference in frequencies of the pair of lasers. The output signal may be a millimeter wave-band signal. The photonic synthesizer can be formed as a photonic integrated circuit (PIC).

Abstract: A photonic synthesizer includes a multifrequency optical source to produce a signal of interest from a pair of lasers, which may be self-injection locked chip lasers. The signal is referenced to a high frequency clock using a photonic mixer/divider based on an electro-optical modulator and a relatively slow photodiode. The electro-optical modulator produces optical harmonics from the beams from the pair of lasers, where one harmonic from the first laser beam and one harmonic from the second laser beam beat on the photodiode. A phase locked control signal is generated for controlling the output frequency of one or both of the two lasers. The output signal of the photonic synthesizer is generated using a relatively fast photodiode based on a difference in frequencies of the pair of lasers. The output signal may be a millimeter wave-band signal. The photonic synthesizer can be formed as a photonic integrated circuit (PIC).

Abstract: Various technologies described herein pertain to variable gain amplification for a sensor application. A multistage variable gain amplifier system provides variable gain amplification of an input signal. The multistage variable gain amplifier system includes a plurality of amplification stages. The multistage variable gain amplifier system further includes a power detector configured to detect a power level of an input signal received by the multistage variable gain amplifier system. The multistage variable gain amplifier system also includes a controller configured to control the amplification stages based on the power level of the input signal. The multistage variable gain amplifier system can output an output signal such that the amplification stages are controlled to adjust a gain applied to the input signal by the multistage variable gain amplifier system to output the output signal.

Abstract: Devices, systems and methods for optical spectroscopy using a Fourier transform that improve measurement speed, and relax the sampling rate and dynamic range requirements compared to conventional techniques, are described. One exemplary method for optical Fourier transform spectroscopy includes receiving a broadband signal, spectrally partitioning the broadband signal to generate a plurality of spectral channel interferograms, computing a one-dimensional Fourier transform of a function of each of the plurality of spectral channel interferograms to generate each of a plurality of channel spectrums, and reconstructing a spectrum of the broadband signal based on the plurality of channel spectrums. Embodiments of the disclosed technology include a free-space channel dispersed Fourier transform spectrometer and an integrated silicon-on-insulator Fourier transform spectrometer.

Abstract: Various technologies described herein pertain to variable gain amplification for a sensor application. A multistage variable gain amplifier system provides variable gain amplification of an input signal. The multistage variable gain amplifier system includes a plurality of amplification stages. The multistage variable gain amplifier system further includes a power detector configured to detect a power level of an input signal received by the multistage variable gain amplifier system. The multistage variable gain amplifier system also includes a controller configured to control the amplification stages based on the power level of the input signal. The multistage variable gain amplifier system can output an output signal such that the amplification stages are controlled to adjust a gain applied to the input signal by the multistage variable gain amplifier system to output the output signal.

Abstract: Various technologies described herein pertain to a time of flight lidar sensor system that uses a coherent detection scheme. The lidar sensor system includes a laser source, a semiconductor optical amplifier, a combiner, and a balanced detector. The laser source emits an input optical signal. The semiconductor optical amplifier receives a first portion of the input optical signal and outputs a modulated optical signal (amplified and modulated). The combiner receives a second portion of the input optical signal and a returned optical signal received responsive to transmission of at least a portion of the modulated optical signal. The combiner coherently mixes the second portion of the input optical signal with the returned optical signal and outputs mixed optical signals. The balanced detector detects the mixed optical signals and generates an output signal (e.g., a differential photocurrent), which can be used to detect a distance to a target.

Abstract: Various technologies described herein pertain to variable gain amplification for a sensor application. A multistage variable gain amplifier system provides variable gain amplification of an input signal. The multistage variable gain amplifier system includes a plurality of amplification stages. The multistage variable gain amplifier system further includes a power detector configured to detect a power level of an input signal received by the multistage variable gain amplifier system. The multistage variable gain amplifier system also includes a controller configured to control the amplification stages based on the power level of the input signal. The multistage variable gain amplifier system can output an output signal such that the amplification stages are controlled to adjust a gain applied to the input signal by the multistage variable gain amplifier system to output the output signal.

Abstract: The technology described in this document can be used to implement beam steering in optical systems and photonic devices, to provide a nonmechanical beam steering system for projecting optical energy and controlling the direction of the optical energy using a collection of devices and components that are fixed in position to selectively direct light from an array of different optical emitters at different locations.

Abstract: Microwave photonic devices use light to carry and process microwave signals over a photonic link. Light can be used as a stimulus to microwave devices that directly control microwave signals. Previous optically controlled devices suffer from large footprint, high optical power level required for switching, lack of scalability and complex integration requirements, restricting their implementation in practical microwave systems. Disclosed are monolithic optically reconfigurable integrated microwave switches (MORIMSs) built on a CMOS compatible silicon photonic chip. The disclosed scalable micrometer-scale switches provide higher switching efficiency and operate using optical power that is orders of magnitude lower than previous devices. The disclosed devices and techniques provide examples of silicon photonic platforms integrating microwave circuitry.

Abstract: Devices, systems and methods for optical spectroscopy using a Fourier transform that improve measurement speed, and relax the sampling rate and dynamic range requirements compared to conventional techniques, are described. One exemplary method for optical Fourier transform spectroscopy includes receiving a broadband signal, spectrally partitioning the broadband signal to generate a plurality of spectral channel interferograms, computing a one-dimensional Fourier transform of a function of each of the plurality of spectral channel interferograms to generate each of a plurality of channel spectrums, and reconstructing a spectrum of the broadband signal based on the plurality of channel spectrums. Embodiments of the disclosed technology include a free-space channel dispersed Fourier transform spectrometer and an integrated silicon-on-insulator Fourier transform spectrometer.