Abstract: An apparatus comprises: a photonic integrated circuit comprising an optical phased array, a first focusing element at a fixed position relative to the optical phased array and configured to couple an optical beam to or from the optical phased array, and a second focusing element at a fixed position relative to the first focusing element and configured to couple the optical beam to or from the first focusing element. At least one of the first or second focusing element is externally coupled to the photonic integrated circuit, and the first and second focusing elements have different effective focal lengths.

Abstract: An apparatus comprises: a photonic integrated circuit comprising an optical phased array, a first focusing element at a fixed position relative to the optical phased array and configured to couple an optical beam to or from the optical phased array, and a second focusing element at a fixed position relative to the first focusing element and configured to couple the optical beam to or from the first focusing element. At least one of the first or second focusing element is externally coupled to the photonic integrated circuit, and the first and second focusing elements have different effective focal lengths.

Abstract: An apparatus includes: an optical phased array (e.g., on a photonic integrated circuit), a focusing element, which can be at a fixed position relative to the optical phased array and configured to receive an optical beam from the optical phased array, and a steering element, which can be at a fixed position relative to the focusing element and configured to transmit the optical beam received from the focusing element. In some implementations, at least one of the focusing element or the steering element is externally coupled to the photonic integrated circuit.

Abstract: An artificial saturable absorber uses additive pulse mode-locking to enable pulse operation of an on-chip laser operation. Four different artificial saturable absorbers are disclosed. The first includes an integrated coupler, two arms each containing some implementation of the end-reflector, and a phase bias element in one arm. The second includes an integrated directional coupler, two integrated waveguide arms, and another integrated coupler as an output. The third includes an integrated birefringent element, integrated birefringent-free waveguide, and integrated polarizer. And the fourth includes a multimode waveguide that allows for different modes to propagate in such a way that the difference in the spatial distribution of intensity causes a nonlinear phase difference between the modes.

Abstract: An artificial saturable absorber uses additive pulse mode-locking to enable pulse operation of an on-chip laser operation. Four different artificial saturable absorbers are disclosed. The first includes an integrated coupler, two arms each containing some implementation of the end-reflector, and a phase bias element in one arm. The second includes an integrated directional coupler, two integrated waveguide arms, and another integrated coupler as an output. The third includes an integrated birefringent element, integrated birefringent-free waveguide, and integrated polarizer. And the fourth includes a multimode waveguide that allows for different modes to propagate in such a way that the difference in the spatial distribution of intensity causes a nonlinear phase difference between the modes.