Abstract: The present invention provides to a novel grating-assisted directional coupler which is capable of appending a nonlinear thin film to a conventional linear grating-assisted directional coupler, to thereby significantly improve coupling efficiency and hence design a structure having optical multistable characteristics, which comprises; a thin film nonlinear optical waveguide with third-order nonlinearity, which having a first thickness; a first linear optical waveguide formed on the thin film nonlinear optical waveguide, which having a second thickness, wherein a linear refractive index of the first linear optical waveguide is more than that of the thin film nonlinear optical waveguide; an optical waveguide grating patterned in equi-distanced on top surface of the nonlinear optical waveguide; and a second optical waveguide formed at a portion which is displaced from top surface of the first linear optical waveguide by a predetermined distance.

Abstract: A structure for a nonlinear grating coupler which is capable of providing a structure that a tapered nonlinear thin film and a linear waveguide grating structure are combined and a nonlinear grating coupler that a stepped nonlinear thin film and a linear optical waveguide grating structure are combined. The structure includes a tapered nonlinear thin film having a third-order nonlinearity, a linear optical waveguide having a refractive index greater than a linear refractive index of a nonlinear thin film formed on the tapered nonlinear thin film, and a grating structure formed on the linear optical waveguide.

Abstract: An improved optical packet address detector which is capable of enabling a high speed packet switching network of 100 Gbps, which includes a glass substrate having a mirror disposed at the back side thereof; a channel optical waveguide formed on the glass substrate and extended in a predetermined direction; a plurality of grating couplers spaced-apart on the channel optical waveguide for dispersing a packet signal beam passing through the channel optical waveguide into the inside of the glass substrate; an optical absorber attached to one end of the channel optical waveguide for absorbing part of the packet signal beam which is not dispersed by the grating coupler; a reflective lens spaced-apart from the optical absorber by a predetermined distance and formed on the glass substrate for focusing the signal beam dispersed by the grating coupler and reflected by the mirror; and a detector spaced-apart from the reflective lens and formed on the glass substrate for detecting the signal beam passing through the ref

Abstract: A nonlinear Y-junction waveguide structure includes a straight linear waveguide, and a nonlinear waveguide partially joined to the linear waveguide and bent through a desired angle at an output end portion thereof, whereby incident light coming into the linear waveguide travels mainly along the linear waveguide when it has a power lower than a predetermined level while traveling mainly along the nonlinear waveguide when it has a power not lower than the predetermined level. The nonlinear Y-junction waveguide structure has an increased branching angle as compared to the conventional completely-operating optical device and exhibits an abrupt switching phenomenon. Accordingly, it is possible to achieve an easy adjustment of the critical power. In this regard, there is no difficulty in the fabrication of the waveguide structure.

Abstract: An improved parallel optical logic operator provides a path for light to pass through substrates in which a light source and an optical logic device are arranged. An optical logic device operates by transmission of light forwarded to a predetermined direction. This increases integration efficiency of the system by eliminating optical parts for changing the light path. A unit chip includes a laser array for generating a predetermined light in accordance with an electrical signal for a logic process, a laser array substrate on which via holes are formed for passing light, a microlens array for converting the light beam emitted from each laser device of the laser array into a parallel light beam for passing through the via hole, and an optical logic circuit array formed with a combination of an S-SEED which performs a logic function by transmission of the light signal through an optical window in S-SEED.

Abstract: The present invention relates to a manufacturing method of a polymer GRIN lens which is used for focusing light in connections for example between two or more optical fibers and between an optical fiber and a light source in the optical communication field. The manufacturing method of a GRIN lens according to the present invention utilizes a characteristic of polystyrene that its refractive-index is decreased by sulfonation. The method includes polymerizing a sphere or rod made of a directional monomer that is capable of sulfonating like a styrene, together with a cross-linking agent, and a polymerization initiator; swelling the polymerized cross-linked polymer by using a predetermined solvent; and sulfonating the swollen cross-linked polymer using a sulfuric acid. Accordingly, the present method can be easily controlled to obtain the desired refractive-index distribution since the refractive-index distribution is determined by the diffusion of the sulfuric acid as a sulfonation.

Abstract: The present invention discloses an optical back-board interconnection module scheme applying optical technique in a back-board interconnection module scheme for distribution of communication signals among opto-electronic integrated circuit (OEIC) boards of data communication network or computer systems with ultra-high speed.The present invention provides a back-board interconnection scheme having out-coupling uniformity level of optical power of below 1% and total out-coupling efficiency of more than 99%, and a method for designing a focusing grating coupler (FGC) array used as an important component in the back-board interconnection scheme and FGC standard specification obtained by such a method.

Abstract: The present invention relates to planar integration of an optical system. The optical system is an integration of a crossover switching network having several optical elements such as mirrors, lenses, beam splitters etc., spatially separated on a single wafer using an acute-angle prism array disposed on the surface of a substrate in which the optical elements are integrated.