An isolator includes a first waveguide with a linear shape and a second waveguide with an annular shape on a substrate including a substrate surface, the first waveguide being positioned along the substrate surface. The first waveguide and the second waveguide each include a core and a cladding. The first waveguide includes a first end, a second end, and a port at each of the first end and the second end for input and output of electromagnetic waves. The core of the second waveguide includes a non-reciprocal member in at least a portion of a cross-section intersecting a direction in which the second waveguide extends.

An optical subassembly for non-reciprocal coupling of light from a planar optical waveguide output to an optical fiber includes a carrier configured to support the optical subassembly, an optical fiber fixed to the optical subassembly, a focusing optical system consisting two foci with one focus coincident with the input of optical fiber, an optical isolator to transmit light unidirectionally between two foci, an input boundary provided by the carrier to align the optical subassembly with the planar optical waveguide output. In particular, the optical subassembly is operably configured to provide a low transmission loss for light traveling from the planar optical waveguide output to the optical fiber.

An isolator includes a substrate, a waveguide and an electronic circuit disposed above the substrate, and a non-reciprocal member disposed above the waveguide and the electronic circuit. The non-reciprocal member includes a first portion in contact with the waveguide and a second portion disposed within a predetermined range from the electronic circuit. Non-reciprocity in the second portion is weaker than non-reciprocity in the first portion.

An integrated optical circulator comprising at least two single-fiber bidirectional optical fiber interfaces (1), a refractive element group (2), an optical isolation element group (3), and an optical fiber array (4), wherein the refractive element group (2) and the optical isolation element group (3) are sequentially arranged on a same optical path; an incident signal light from each single-fiber bidirectional optical fiber interface (1) sequentially passes through the refractive element group (2) and the optical isolation element group (3), then is output by a corresponding outgoing optical fiber (43, 44) of the optical fiber array (4); the incident signal light from each incident optical fiber (41, 42) of the optical fiber array (4) sequentially passes through the optical isolation element group (3) and the refractive element group (2), and is output by the corresponding single-fiber bidirectional optical fiber interface (1). Multiple optical circulators are integrated within the volume of a same optical circulator, thereby reducing the volume occupied by optical circulators in an overall device, lowering the overall cost of the device, and improving the convenience of optical path integration.

An isolator includes a substrate having a substrate surface, a waveguide, a groove, a mask, and a non-reciprocal member. The waveguide is disposed above the substrate surface and has a first surface facing the substrate surface, a second surface opposite the first surface, and a side face connecting the first surface to the second surface. The groove includes a bottom portion and a side portion configured to expose at least part of the side face of the waveguide. The mask is disposed above and overlaps at least a region of the second surface of the waveguide, as viewed in a direction normal to the substrate surface. The region of the second surface of the waveguide is in contact with the groove. The non-reciprocal member is disposed in the groove and is in contact with the side face of the waveguide.

A magnetic field sensor comprises a magnetically responsive light propagating component configured to cause a polarization of light propagating inside the component to be rotated in response to an applied magnetic field, wherein the magnetically responsive light propagating component is formed of a bulk material doped with a dopant, the dopant including at least gadolinium, the dopant concentration being at a sufficiently low concentration such that the dopant is uniformly dispersed in the bulk material to provide a high Verdet constant. The magnetic field sensor also comprises a detector, and a polarization-maintaining light input device to couple the light into the magnetically responsive light propagating component. The detector is configured to measure a property of light output from the magnetically responsive light propagating component to determine a change in polarization of the light, the change caused by the presence of a magnetic field.

An integrated photonic circulator is described, an application of which may be deployed on a chip-scale light-detection and ranging (LiDAR) device. The photonic circulator includes a micro-ring resonator waveguide, a heating element, first and second bus waveguides, a magneto-optic substrate, a magneto-optic element, a magnetic ring disposed on a photonic substrate, and a silicon substrate. The first and second bus waveguides are coupled to the micro-ring resonator waveguide, and the micro-ring resonator waveguide is affixed onto a first side of the photonic substrate. The magneto-optic element and the magneto-optic substrate are arranged on the micro-ring resonator waveguide, the magnetic ring is affixed to the magneto-optic substrate, the heating element is affixed to the photonic substrate, the photonic substrate is affixed to the silicon substrate, and the magnetic ring is concentric with the micro-ring resonator.

An architecture for a chip-scale optical phased array-based scanning frequency-modulated continuous wave (FMCW) Light-detection and ranging (LiDAR) device is described. The LiDAR device includes a laser, a transmit optical splitter, an optical circulator, photodetectors, and an optical phased array. The laser, the transmit optical splitter, the optical circulator, the photodetectors, and the optical phased array are arranged as a chip-scale package on a single semiconductor substrate. The laser generates a first light beam that is transmitted to the optical phased array aperture via the transmit optical splitter, the optical circulator, and the optical phased array. A fraction of the first light beam is transmitted to the photodetectors via the transmit optical splitter to serve as the optical local oscillator (LO), the aperture of the optical phased array captures a second light beam that is transmitted to the photodetectors via the optical phased array and the optical circulator.

An apparatus including a light detection and ranging (LiDAR) antenna of an optical phased array includes a silicon-on-insulator substrate including a silicon wire waveguide embedded within the substrate and a grating layer disposed over the substrate. The grating layer includes a silicon nitride layer coating the silicon-on-insulator substrate and including a plurality of etchings formed in a direction perpendicular to a longitudinal axis of the optical phased array and a silicon oxynitride layer coating the silicon nitride layer and filling the etchings. The etchings are relatively thin in the direction of the longitudinal axis of the optical phased array at a first end of the optical antenna and are relatively thick in the direction of the longitudinal axis at a second end. The etchings gradually increase in thickness between the first end of the optical phased array and the second end of the optical antenna.

An isolator includes a first core, a second core, a nonreciprocal member, and a magnetic body. The first core and the second core extend in a first direction and are positioned side by side with a cladding therebetween in a second direction that intersects the first direction. The nonreciprocal member is in contact with at least a part of the second core while being positioned side by side with the second core in the second direction. In a magnetic field generated by the magnetic body in a portion where the nonreciprocal member is positioned, a component in a third direction perpendicular to the first direction and the second direction is greater than any component other than the component in the third direction.