An optical device includes a first waveguide that propagates light in a first direction; and a second waveguide including a first mirror, a second mirror, and an optical waveguide layer. The first mirror extends in the first direction and has a first reflecting surface, and the second mirror extends in the first direction and has a second reflecting surface. The optical waveguide layer is located between the first and second mirrors and propagates the light in the first direction. A forward end portion of the first waveguide is disposed inside the optical waveguide layer. In a region in which the first and second waveguides overlap each other when viewed in a direction perpendicular to the first reflecting surface, at least part of the first waveguide and/or at least part of the second waveguide includes at least one grating whose refractive index varies periodically in the first direction.

A photonic calorimeter converts ionizing radiation dose to heat and includes: a radiation absorber, a temperature compensator disposed within the radiation absorber, a compensation waveguide, a compensation resonator, a compensation resonator, a thermal isolator on which the radiation absorber is disposed and that thermally isolates the radiation absorber from heat loss by thermal transfer due to physical contact by an object, and the temperature compensator changes the optical resonance of the compensation resonator in response to a change in temperature of the radiation absorber due to absorption of the ionizing radiation by the radiation absorber.

The present disclosure relates to an optical waveguide system. The system may include a first waveguide having a core-guide and a material portion surrounding and encasing the core-guide. The core-guide enables a core-guide mode for an optical signal travelling through the core-guide. A second waveguide forms a lossy waveguide on an outer surface of the first waveguide. The construction of the second waveguide is such as to achieve a desired coupling between the core-guide mode and the lossy waveguide to control an energy level of the optical signal travelling through the core-guide.

In one embodiment, a wide-band laser beam is split into a plurality of sub-laser beams, with each sub-laser beam at a discrete wavelength. Each of the sub-laser beams is transmitted simultaneously through an antenna, with each sub-laser beam transmitted at a different angle due to properties of the antenna. Sub-laser beams that reflect of an object are received back at the same, or a different, antenna and passed to a demultiplexor. The demultiplexor passes each sub-laser to a different waveguide based on the discrete wavelength associated with each sub-laser beam. A detector receives the sub-lasers beam through the waveguides, and calculates the positions of various points on the object based in-part on which waveguide each sub-laser beam is received from and the frequency of each sub-laser beam.

A grating coupler having first and second ends for coupling a light beam to a waveguide of a chip includes a substrate configured to receive the light beam from the first end and transmit the light beam through the second end, the substrate having a first refractive index n1, a grating structure having curved grating lines arranged on the substrate, the grating structure having a second refractive index n1, wherein the curved grating lines have line width w and height d and are arranged by a pitch , wherein the second refractive index n2 is less than first refractive index n1, and a cladding layer configured to cover the grating structure, wherein the cladding layer has a third refractive index n3.

A grating coupler having first and second ends for coupling a light beam to a waveguide of a chip includes a substrate configured to receive the light beam from the first end and transmit the light beam through the second end, the substrate having a first refractive index n1, a grating structure having curved grating lines arranged on the substrate, the grating structure having a second refractive index n1, wherein the curved grating lines have line width w and height d and are arranged by a pitch , wherein the second refractive index n2 is less than first refractive index n1, and a cladding layer configured to cover the grating structure, wherein the cladding layer has a third refractive index n3.

A photonic dosimeter accrues cumulative dose and includes: a substrate; a waveguide disposed on the substrate and that: receives a primary input light; transmits secondary input light from the primary input light to a dosimatrix; receives a secondary output light from the dosimatrix; and produces primary output light from the secondary output light; the dosimatrix disposed on the substrate and in optical communication with the waveguide and that: receives the secondary input light from the waveguide; produces the secondary output light that is communicated to the waveguide; and includes an active element that undergoes conversion from a prime state to a dosed state in response to receipt, by the active element, of a dose of radiation; and a cover layer disposed on waveguide and the dosimatrix.

An optical waveguide comprises one or more upstream diffraction gratings in addition to overlapping first and second downstream diffraction gratings. The one or more upstream diffraction gratings include a first upstream diffraction grating configured to receive display light and to release the display light expanded along a first axis. The first and second downstream diffraction gratings are configured to receive the display light expanded along the first axis and to cooperatively release the display light further expanded along a second axis. The first downstream diffraction grating is arranged on a planar face of the optical waveguide and is further configured to further expand along the first axis the display light expanded along the first axis.

A grating coupler having first and second ends for coupling a light beam to a waveguide of a chip includes a substrate configured to receive the light beam from the first end and transmit the light beam through the second end, the substrate having a first refractive index n1, a grating structure having curved grating lines arranged on the substrate, the grating structure having a second refractive index n1, wherein the curved grating lines have line width w and height d and are arranged by a pitch , wherein the second refractive index n2 is less than first refractive index n1, and a cladding layer configured to cover the grating structure, wherein the cladding layer has a third refractive index n3.

An optical waveguide that performs both in-coupling and out-coupling using two diffractive optical elements is provided. Each optical element is a diffraction grating and can be applied to the same or different surface of the optical waveguide. The diffraction gratings overlap to form two overlapping regions. The first overlapping region in-couples light into the waveguide and the second overlapping region out-couples light from the optical waveguide. Because the optical waveguide only uses two gratings, and therefore only has two grating vectors, the optical waveguide is easier to manufacture than optical waveguides with a greater number of grating vectors.