A novel apparatus for bonding of two polished substrates includes a plasma source in a ultra-high vacuum (UHV) chamber and a wafer-guiding element to control and guide wafers in the UHV chamber, where after a plasma activation process the wafers are guided and pressed against each other to form a covalent bond between wafer surfaces. The plasma activation process involves deposition of mono-layer or sub-monolayer metallic atom on the surface of substrates. After deposition of metallic layers, a high-force actuation presses the wafers and forms a covalent bond between the wafers. Then, the bonded wafer pair is ion-sliced or thinned to form single crystalline optical thin film. An annealing process oxidizes the deposited metallic layers and produces optically-transparent single crystalline thin film. An optical waveguide may be fabricated by this thin film while utilizing an electro-optic effect to produce optical modulators and other photonic devices.

A novel apparatus for bonding of two polished substrates includes a plasma source in a ultra-high vacuum (UHV) chamber and a wafer-guiding element to control and guide wafers in the UHV chamber, where after a plasma activation process the wafers are guided and pressed against each other to form a covalent bond between wafer surfaces. The plasma activation process involves deposition of mono-layer or sub-monolayer metallic atom on the surface of substrates. After deposition of metallic layers, a high-force actuation presses the wafers and forms a covalent bond between the wafers. Then, the bonded wafer pair is ion-sliced or thinned to form single crystalline optical thin film. An annealing process oxidizes the deposited metallic layers and produces optically-transparent single crystalline thin film. An optical waveguide may be fabricated by this thin film while utilizing an electro-optic effect to produce optical modulators and other photonic devices.

An optical element includes an optical waveguide layer. The optical waveguide includes a periodic structure of grooves. The optical waveguide layer has a layer-thickness equal to or greater than 1.5 m and is made of material selected from a group consisting of Ta2O5, Al2O3, LiNbO3, LiTaO3, AlN, GaN, SiC, and Yttrium aluminum garnet (YAG). (D/0.5)2.5 is satisfied where D indicates the depth of groove; and indicates the pitch of the arranged grooves in the periodic structure. The unit of is identical to the unit of D.

A novel apparatus for bonding of two polished substrates includes a plasma source in a ultra-high vacuum (UHV) chamber and a wafer-guiding element to control and guide wafers in the UHV chamber, where after a plasma activation process the wafers are guided and pressed against each other to form a covalent bond between wafer surfaces. The plasma activation process involves deposition of mono-layer or sub-monolayer metallic atom on the surface of substrates. After deposition of metallic layers, a high-force actuation presses the wafers and forms a covalent bond between the wafers. Then, the bonded wafer pair is ion-sliced or thinned to form single crystalline optical thin film. An annealing process oxidizes the deposited metallic layers and produces optically-transparent single crystalline thin film. An optical waveguide may be fabricated by this thin film while utilizing an electro-optic effect to produce optical modulators and other photonic devices.

An optical device is described. At least a portion of the optical device includes ferroelectric non-linear optical material(s) and is fabricated utilizing ultraviolet lithography. In some aspects the at least the portion of the optical device is fabricated using deep ultraviolet lithography. In some aspects, the short range root mean square surface roughness of a sidewall of the at least the portion of the optical device is less than ten nanometers. In some aspects, the at least the portion of the optical device has a loss of not more than 2 dB/cm.

An optical device is described. At least a portion of the optical device includes ferroelectric non-linear optical material(s) and is fabricated utilizing ultraviolet lithography. In some aspects the at least the portion of the optical device is fabricated using deep ultraviolet lithography. In some aspects, the short range root mean square surface roughness of a sidewall of the at least the portion of the optical device is less than ten nanometers. In some aspects, the at least the portion of the optical device has a loss of not more than 2 dB/cm.

An optical element includes an optical waveguide layer. The optical waveguide includes a periodic structure of grooves. The optical waveguide layer has a layer-thickness equal to or greater than 1.5 m and is made of material selected from a group consisting of Ta2O5, Al2O3, LiNbO3, LiTaO3, AlN, GaN, SiC, and Yttrium aluminum garnet (YAG). (D/0.5)2.5 is satisfied where D indicates the depth of groove; and indicates the pitch of the arranged grooves in the periodic structure. The unit of is identical to the unit of D.

An example method of forming a deterministic thin film from a crystal substrate is described herein. The method can include implanting ions into a surface of the crystal substrate to form a thin film crystal layer, and bonding the crystal substrate and a handle substrate to form a bilayer bonding interface between the crystal substrate and the handle substrate. The method can also include exfoliating the thin film crystal layer from the crystal substrate, patterning the thin film crystal layer to define a deterministic thin film, etching one or more trenches in the thin film crystal layer, etching the bilayer bonding interface via the one or more trenches, and releasing the deterministic thin film from the handle substrate.

An optical device includes: a substrate; and at least two optical waveguides formed on the substrate and facing a multiplexed portion on the substrate in a light propagation direction, wherein in a cross section perpendicular to the light propagation direction, an angle formed between the substrate and a side surface of one optical waveguide, which faces the other optical waveguides, is set to ?, and an angle formed between the substrate and a side surface of one optical waveguide, which does not face the other optical waveguides, is set to ?, satisfying ?<?, wherein ??90?, and ??90?. Therefore, light propagating through the at least two optical waveguides tends to propagate between the optical waveguides when approaching the multiplexed portion. As a result, the light transmission loss during multiplexing light can be reduced.

An optical device, including a substrate and a plurality of optical waveguide paths formed on the substrate and having slab portions with different thicknesses.