The disclosure describes vacuum cell assemblies that integrate a vacuum envelope with a photonic integrated circuit (PIC). Walls of the vacuum envelope are coupled to the PIC, such as through anodic bonding, so that the PIC forms at least one wall of the vacuum envelope and provides an optically accessible medium and surface for transmitting and distributing light into various cavities of the vacuum envelope through one or more nonplanar waveguides. A surface of the PIC may include a material that is compatible with a material of the walls of the vacuum envelope, such as a silicon-based vacuum envelope bonded to a silicon nitride or amorphous silicon surface of the PIC. Each waveguide may include a bridge structure that forms a planar surface for tightly bonding with the vacuum envelope and preserves properties of the transmitted light between opposing sections of the waveguide.

An embodiment is an optical connection element including a first waveguide core and a second waveguide core on a substrate, the first waveguide core and the second waveguide core configured to propagate a signal light and a resin-curing light, and a mode field conversion portion provided at one end of the first waveguide core, wherein the second waveguide core covers at least the mode field conversion portion on the substrate, and a refractive index of the first waveguide core is higher than a refractive index of the second waveguide core.

An embodiment is an optical connection element including a first waveguide core and a second waveguide core on a substrate, the first waveguide core and the second waveguide core configured to propagate a signal light and a resin-curing light, and a mode field conversion portion provided at one end of the first waveguide core, wherein the second waveguide core covers at least the mode field conversion portion on the substrate, and a refractive index of the first waveguide core is higher than a refractive index of the second waveguide core.

A cavity substrate may have a directional optoelectronic transmission channel. The cavity substrate includes a support frame, a first dielectric layer on a first surface of the support frame, and a second dielectric layer on a second surface of the support frame. The support frame, the first dielectric layer and the second dielectric layer constitute a closed cavity having an opening on one side in the length direction of the substrate, a first circuit layer is arranged on the inner surface of the first dielectric layer facing the cavity, an electrode connected with an optical communication device is arranged on the first circuit layer, the electrode is electrically conducted with the first circuit layer, a second circuit layer is arranged on the outer surfaces of the first dielectric layer and the second dielectric layer, and the first circuit layer and the second circuit layer are communicated through a via column.

A cavity substrate may have a directional optoelectronic transmission channel. The cavity substrate includes a support frame, a first dielectric layer on a first surface of the support frame, and a second dielectric layer on a second surface of the support frame. The support frame, the first dielectric layer and the second dielectric layer constitute a closed cavity having an opening on one side in the length direction of the substrate, a first circuit layer is arranged on the inner surface of the first dielectric layer facing the cavity, an electrode connected with an optical communication device is arranged on the first circuit layer, the electrode is electrically conducted with the first circuit layer, a second circuit layer is arranged on the outer surfaces of the first dielectric layer and the second dielectric layer, and the first circuit layer and the second circuit layer are communicated through a via column.

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.

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 optical fiber includes a glass fiber including: a core and a cladding; and a coating resin layer coating the glass fiber in contact with the glass fiber; wherein the coating resin layer has a primary resin layer coating the glass fiber in contact with the glass fiber and a secondary resin layer coating the primary resin layer, the primary resin layer contains a cured product of a first resin composition containing a photopolymerizable compound and a phosphine oxide-based photopolymerization initiator, the secondary resin layer contains a cured product of a second resin composition containing a photopolymerizable compound and a phosphine oxide-based photopolymerization initiator, and an amount of the phosphine oxide-based photopolymerization initiator remaining unreacted in the coating resin layer is 0.5 mass % or less.

A beam splitter arrangement for an optoelectronic sensor, an optoelectronic sensor having such a beam splitter arrangement, and a method of beam splitting in an optoelectronic sensor are provided, wherein the beam splitter arrangement has at least one input for coupling first transmitted light beams having first transmitted light pulses into the beam splitter arrangement. At least one beam splitter splits the first transmitted light beams into a plurality of second transmitted light beams having second transmitted light pulses. The beam splitter arrangement further has a plurality of outputs for decoupling the second transmitted light beams from the beam splitter arrangement, with the number of outputs being greater than the number of inputs. Optical compression paths that compress the second transmitted light pulses such that a second pulse length of the second transmitted light pulses is shorter than a first pulse length of the first transmitted light pulses are arranged downstream of at least one beam splitter.

A method to form a three-dimensional photonic crystal template with a gradient structure involves irradiating a photoresist composition of a thickness of at least 15 μm from at least four laser beams to yield a periodic patterned with a percolating matrix of mass in constructive volumes of a cured photoresist composition and destructive volumes of voids free of condensed matter where the proportion of constructive volume displays a gradient from the irradiated surface to the substrate after development. For a given light intensity, photoinitiator concentration in the photoresist composition, and a given thickness, by irradiating for a relatively short period, a three-dimensional photonic crystal template displaying a gradient having greater constructive volume proximal the air interface forms and a relatively long irradiation period results in a gradient having greater constructive volume proximal the substrate.