Abstract: Disclosed are an optical input/output device and an opto-electronic system including the same. The device includes a bulk silicon substrate, at least one vertical-input light detection element monolithically integrated on a portion of the bulk silicon substrate, and at least one vertical-output light source element monolithically integrated on another portion of the bulk silicon substrate adjacent to the vertical-input light detection element. The vertical-output light source element includes a III-V compound semiconductor light source active layer combined with the bulk silicon substrate by a wafer bonding method.

Abstract: Provided is a wavelength division device. The wavelength division device includes input arrayed waveguides, an input circular grating coupler connected to one ends of the input arrayed waveguides and configured to refract first light having a plurality of wavelengths and output the refracted first light to each of the one ends of the input arrayed waveguides as plurality of second light, and an output star coupler connected to the other ends of the input arrayed waveguides and configured to receive the plurality of second light from the other ends of the input arrayed waveguides and output optical signals that are divided for each wavelength. The input circular grating coupler includes a plurality of circular gratings.

Abstract: Provided is an optical modulator including an optical waveguide and an optical modulation part integrated on the optical waveguide that is clad in oxide silicon and has silicon as core by using a bulk silicon wafer in place of an silicon-on-insulator (SOI) used for a typical optical waveguide and optical modulator and using complementary metal oxide semiconductor (CMOS) and thermal oxide film formation processes, and a fabrication method thereof.

Abstract: Provided is a wavelength combiner including a slab waveguide; an output waveguide extended from the slab waveguide in a first direction; and at least one rib waveguide disposed at an interval horizontally from the output waveguide and extended from the slab waveguide in the first direction, wherein the rib waveguide is tapered in the first direction.

Abstract: An optical coupling device comprises an optical fiber block including a first block part and a second block part contacting with one side of the first block part, an optical fiber penetrating the optical fiber block and having an end surface exposed at a bottom surface of the optical fiber block, a semiconductor chip disposed below the optical fiber block and having an optical input/output element disposed on a top surface of the semiconductor chip to correspond with the end surface of the optical fiber, and a planarization layer disposed on the top surface of the semiconductor chip and having a recess region. A bottom surface of the first block part has a higher level than that of the second block part. The bottom surface of the second block part contacts with a bottom of the recess region. The optical fiber is optically coupled with the optical input/output element.

Abstract: An optical coupling device comprises an optical fiber block including a first block part and a second block part contacting with one side of the first block part, an optical fiber penetrating the optical fiber block and having an end surface exposed at a bottom surface of the optical fiber block, a semiconductor chip disposed below the optical fiber block and having an optical input/output element disposed on a top surface of the semiconductor chip to correspond with the end surface of the optical fiber, and a planarization layer disposed on the top surface of the semiconductor chip and having a recess region. A bottom surface of the first block part has a higher level than that of the second block part. The bottom surface of the second block part contacts with a bottom of the recess region. The optical fiber is optically coupled with the optical input/output element.

Abstract: Provided is a germanium-on-insulator substrate. The germanium-on-insulator substrate includes a bulk silicon substrate, an oxide film which is disposed on the bulk silicon substrate and has a first region exposing a portion of the bulk silicon substrate, a silicon layer which covers a portion of the top surface of the oxide film and does not cover the first region, a germanium layer which contacts the bulk silicon substrate exposed through the first region and is disposed on the oxide film, and an insulating layer which covers the oxide film and the silicon layer and exposes the top surface of the germanium layer.

Abstract: Provided is a wavelength combiner including a slab waveguide; an output waveguide extended from the slab waveguide in a first direction; and at least one rib waveguide disposed at an interval horizontally from the output waveguide and extended from the slab waveguide in the first direction, wherein the rib waveguide is tapered in the first direction.

Abstract: Provided is a photodetector including a substrate, a first doped region on the substrate, a second doped region having a ring structure, wherein the second doped region is provided in the substrate, surrounds the first doped region and is horizontally spaced apart from a side of the first doped region, an optical absorption layer on the first doped region, a contact layer on the optical absorption layer, a first electrode on the contact layer, and a second electrode on the second doped region.

Abstract: Provided is an optical modulator including an optical waveguide and an optical modulation part integrated on the optical waveguide that is clad in oxide silicon and has silicon as core by using a bulk silicon wafer in place of an silicon-on-insulator (SOI) used for a typical optical waveguide and optical modulator and using complementary metal oxide semiconductor (CMOS) and thermal oxide film formation processes, and a fabrication method thereof

Abstract: Provided is a flat-top mode generating device. The flat-top mode generating device includes an input waveguide, a double-tapered structure connected to the input waveguide, and an input star coupler connected to the double-tapered structure. The double-tapered structure includes a first part having a first height hat is equal to that of each of the input waveguide and the input star coupler, and a second part disposed in the first part on the plane and having a second height that is less than the first height, the second part being tapered from the input star coupler toward the input waveguide.

Abstract: Provided are an optical coupler and an optical device including the same. The optical coupler includes: a substrate; a buffer layer on the substrate; and an optical coupling layer including a horizontal mode expander layer and a vertical mode expander layer, wherein the horizontal mode expander layer expands in one direction on the buffer layer, and wherein the vertical mode expander layer adjusts a stepped difference between the horizontal mode expander layer and a plurality of optical transmission devices having different diameters or sectional areas and connected to both sides of the horizontal mode expander layer, and the vertical mode expander layer is disposed on a side of the horizontal mode expander layer to minimize optical loss between the plurality of optical transmission devices.

Abstract: Provided is a method of fabricating a semiconductor laser. The method includes: providing a semiconductor substrate including a first region and a second region; forming a silicon single crystal layer in the second region of the semiconductor substrate by using a selective epitaxial growth process; forming an optical coupler by using the silicon single crystal layer; and forming a laser core structure including a germanium single crystal layer in the first region of the semiconductor substrate by using a selective epitaxial growth process.

Abstract: Provided is a silicon-wafer-based germanium semiconductor photodetector configured to be able to provide properties of high gain, high sensitivity, and high speed, at a relatively low voltage. A germanium-based carrier multiplication layer (e.g., a single germanium layer or a germanium and silicon superlattice layer) may be provided on a silicon wafer, and a germanium charge layer may be provided thereon, a germanium absorption layer may be provided on the charge layer, and a polysilicon second contact layer may be provided on the absorption layer. The absorption layer may be configured to include germanium quantum dots or wires.

Abstract: Provided are an optical coupler and an arrayed-waveguide grating structure including the same. The coupler includes a lower clad layer, a core comprising a slab waveguide region disposed on one side of the lower clad layer and a ridge waveguide region disposed on the other side of the lower clad layer, and an upper clad disposed on the core, wherein the ridge waveguide region comprises a self-focusing region configured to focus an optical signal provided form the slab waveguide region and thus to prevent scattering of the optical signal.

Abstract: Provided are an optical coupler and an optical device including the same. The optical coupler includes: a substrate; a buffer layer on the substrate; and an optical coupling layer including a horizontal mode expander layer and a vertical mode expander layer, wherein the horizontal mode expander layer expands in one direction on the buffer layer, and wherein the vertical mode expander layer adjusts a stepped difference between the horizontal mode expander layer and a plurality of optical transmission devices having different diameters or sectional areas and connected to both sides of the horizontal mode expander layer, and the vertical mode expander layer is disposed on a side of the horizontal mode expander layer to minimize optical loss between the plurality of optical transmission devices.

Abstract: Provided is a vertical-cavity surface-emitting laser (VCSEL). The VCSEL includes a silicon substrate, a lower reflective layer disposed on the silicon substrate, a light generation laser disposed on the lower reflective layer, and an upper reflective layer disposed on the light generation layer. The lower reflective layer, the light generation layer, and the upper reflective layer may include a III-V semiconductor light source-active layer monolithically integrated on a first impurity layer by wafer bonding.

Abstract: An optical device module includes a substrate, an interlayer insulating layer on the substrate, an optical waveguide on the interlayer insulating layer, an optical device on the optical waveguide, and a prism disposed between the optical device and the optical waveguide. The prism has a refractive index greater than a refractive index of the optical waveguide.

Abstract: An interface circuit configured to transmit and receive signals between electronic devices is provided.

Abstract: Provided are an optical connector capable of improving optical alignment efficiency and an optical device having the same. The connector may include a body having a top surface and a bottom surface facing each other, through holes penetrating the body to connect the top and bottom surfaces, and alignment keys provided on at least side surface of the body to be parallel to the through holes.