The invention relates to a beam polarization rotator, which comprises: (a) a waveguide having an input facet, an output facet, and four side facets; (b) a core material of the waveguide having a first refractive index; (c) a coating material of the side facets having a refractive index lower than said refractive index of the core material; wherein the waveguide has a cuboid-twisted shape, such that a distal portion of an originally cuboid body is twisted at an angle α about a longitudinal-central axis of the waveguides body, while a proximal portion of the body remains fixed relative to said axis, resulting in said output facet be at an offset orientation angle α relative to the orientation of said input facet.

A LiDAR system has a field of view and includes a polarization-based waveguide splitter. The splitter includes a first splitter port, a second splitter port and a common splitter port. A laser is optically coupled to the first splitter port via a single-polarization waveguide. An objective lens optically couples each optical emitter of an array of optical emitters to a respective unique portion of the field of view. An optical switching network is coupled via respective dual-polarization waveguides between the common splitter port and the array of optical emitters. An optical receiver is optically coupled to the second splitter port via a dual-polarization waveguide and is configured to receive light reflected from the field of view. A controller, coupled to the optical switching network, is configured to cause the optical switching network to route light from the laser to a sequence of the optical emitters according to a temporal pattern.

An integrated waveguide polarizer comprising: a plurality of silicon layers and a plurality of silicon-nitride layers; each of the plurality of silicon layers and each of the plurality of silicon-nitride layers having a first end and an opposite second end, the first end having a wide width and the second end having a narrow width, such that each silicon layer and each silicon-nitride layer have tapered shapes; wherein the pluralities of silicon and silicon-nitride layers are overlapped, such that at least a portion of each silicon-nitride layer overlaps at least a portion of each silicon layer; and a plurality of oxide layers disposed between the pluralities of silicon-nitride and silicon layers, each oxide layer creating a separation spacing between each silicon-nitride and each silicon layers; wherein, when an optical signal is launched through the integrated waveguide polarizer, the optical signal is transitioned between each silicon-nitride layer and each silicon layer.

A three-dimensional photonic integrated structure includes a first semiconductor substrate and a second semiconductor substrate. The first substrate incorporates a first waveguide and the second semiconductor substrate incorporates a second waveguide. An intermediate region located between the two substrates is formed by a one dielectric layer. The second substrate further includes an optical coupler configured for receiving a light signal. The first substrate and dielectric layer form a reflective element located below and opposite the grating coupler in order to reflect at least one part of the light signal.

An optical device includes a light source configured to provide illumination light and a waveguide. The waveguide has an input surface, an output surface distinct from and non-parallel to the input surface, and an output coupler. The waveguide is configured to receive, at the input surface, the illumination light provided by the light source and propagate the illumination light via total internal reflection. The waveguide is also configured to redirect, by the output coupler, the illumination light so that the illumination light is output from the output surface for illuminating a spatial light modulator.

A single-ended output circulator includes a three-core optical fiber head having first, second, and third optical fiber cores; a walk-off crystal having a first surface facing towards the second end of the three-core optical fiber head tube and a second surface facing away from the second end of the three-core optical fiber head tube; a plurality of half-wave plates each having a first surface coupled to the second surface of the walk-off crystal and a second surface facing away from the second surface of the walk-off crystal; a collimating lens having a first end and a second end; a reflection mirror configured to reflect light beams from the collimating lens; an optical prism between the collimating lens and the reflection mirror and configured to transmit a light beam along a propagation direction according to a polarization direction of the light beam; and a polarization rotator.

An optical device for providing illumination light includes an optical waveguide and a plurality of polarization selective elements. The plurality of polarization selective elements is disposed adjacent to the optical waveguide so that a respective polarization selective element receives light in a first direction, and redirects a first portion of the light in a second direction. A second portion, distinct from the first portion, of the light undergoes total internal reflection, thereby continuing to propagate inside the optical waveguide.

Embodiments of the disclosure provide an optical polarizer with a varying vertical thickness, and methods to form the same. An optical polarizer according to the disclosure may include a first waveguide core over a semiconductor substrate. A first cladding material is on at least an upper surface of the first waveguide core. A second waveguide core over the first waveguide core and above the first cladding material. The second waveguide core includes a first segment having a vertical thickness that varies along a length of the first segment. A second cladding material is at least partially surrounding the second waveguide core. Transfer of one of a transverse electric (TE) mode signal and a transverse magnetic (TM) mode signal from the first waveguide core to the second waveguide core occurs between the first segment of the second waveguide core and the first waveguide core.

A silicon photonic device includes a silicon-on-insulator substrate, a waveguide, and a plate. The silicon-on-insulator substrate includes a silicon layer and a silicon dioxide layer. The waveguide is disposed on the silicon-on-insulator substrate. The silicon dioxide layer at least partially overlays the waveguide. The plate exhibits metallic characteristics and is at least partially embedded in the silicon dioxide layer of the silicon-on-insulator substrate. The plate is spaced apart from the waveguide and is configured to mitigate transverse magnetic emission propagating through the waveguide.

A method using femtosecond laser for nano precision preparation. Initial damage nanoholes formed by using femtosecond laser multiphoton excitation are used as a seed structure, and the energy and polarization state of subsequent laser pulses are adjusted in real time, such that uniform and directional optical near-field enhancement is generated near the seed structure and finally the high-precision removal of machined materials is realized. Benefiting from the high localization of near-field spot energy in space, the method uses femtosecond laser pulses having the wavelength of 800 nm to achieve a machining accuracy having the minimum linewidth of only 18 nm, and the linewidth resolution reaches 1/40 of the wavelength; and the method using femtosecond laser for nano precision preparation does not need a vacuum environment, having good air/solution machining compatibility.