Abstract: A coherent multi-beam optical phased array for radio-frequency beamforming is provided. The optical phase array includes an optical signal source generating an optical signal, a first set of waveguides connected to the optical signal source and configured to propagate the optical signal, a second set of waveguides, a set of splitters along each of the first set of waveguides configured to split the optical signal, a phase shifter coupled to each of the splitters, each phase shifter being controllable to modify a phase shift of the optical signal, a coupler connected to each of the phase shifters and to one waveguide of the second set of waveguides for introducing the optical signal after shifting, and a photodetector coupled to each waveguide of the second set of waveguides and configured to receive a heterodyne optical signal from the waveguide and generate a corresponding electrical signal.

Abstract: A photonic apparatus for use in radiofrequency beamforming, with support for multiple users, is provided. An optical crossbar array is coupled to a transmit or receive antenna array. Controllable devices such as attenuators or switches operate to produce complex-weighted versions of optical input signals, and the complex weightings are generated in support of beamforming operations. Delay elements can also be provided to compensate for synchronization losses due to different optical path lengths in the array.

Abstract: A method of beamforming by which a signal can be received into an array of channels, each of which is split into a real-part sub-channel and an imaginary part sub-channel. In each sub-channel, optical waves are used to carry the signal via waveguides. Each channel includes a real-part sub-channel where an optical wave is scaled by the real part of a complex number, and an imaginary part sub-channel, where a complementary optical wave is scaled by the complex part of the same complex number. When the complementary optical waves are received at the channel's output, they can be shifted by the phase of the complex number having defined their scaling. By processing a signal with a system operative to perform such method, the application of a different phase to each channel can result in a beamforming of the signal.

Abstract: A photonic device configured to perform matrix vector multiplication operations at high frequencies is provided. The vector being multiplied by the matrix is defined by vector components at specific wavelengths. The device includes a first waveguide and a second waveguide. A series of tunable microring resonators (MRRs) are coupled to the first waveguide and to a respective series of passive delay rings (PDRs), which are coupled to the second waveguide. Each MRR/PDR pair defines a tunable matrix component (tunable weight) for a respective wavelength component of the vector. A series of controllable delay elements (CDEs) such as all-pass filters are coupled to the first waveguide, upstream from the tunable MRRs. Any tuning dependent group delay caused by the MRR/PDR pairs can be compensated by controlling the CDEs such that each wavelength components has substantially a same delay as the other wavelength components.