Shigeaki Ohke

Optical waveguides using GaAs-AlxGa1−xAs multiple quantum well

Abstract For the purpose of using the multiple quantum well structure as an optical waveguide of nonlinear-optical devices, GaAs-Al x Ga 1- x As MQW structure is investigated theoretically. The composition ratios of the composing compound semiconductors can provide flexibility for the design of those devices. The numerically calculated result of the field distributions of the MQW waveguide structures showed that they can be approximated by replacing the MQW core section with a uniform material whose refractive index equals the root-mean-square value of the refractive indices of the MQW core section when the MQW structural (quantum wells and barriers) dimensions are less than ∼ 200 A for the near-infrared region.

Power-Limiting Action of Optical Waveguide Having Negative Nonlinear Claddings

In a three-layer slab optical waveguide with claddings having a negative nonlinear refractive index, power-limiting action along the propagation direction is investigated numerically. Light propagating behavior with power leak in the steady state propagation is demonstrated. Assuming a close-to-available material and structural parameters, a short waveguide structure of this kind is found capable of providing a sufficient power-limiting action.

Waveguiding Characteristics of Optical Waveguide with Claddings Having Negative Nonlinear Refractive Coefficient

Waveguiding characteristics of the optical waveguide with claddings having a negative nonlinear refractive coefficient are investigated theoretically. The relationship between the total light intensity and the effective refractive index is obtained by means of numerical computation based on the multisegmentation procedure. As the result, an anomalous optical power-limiting action of this nonlinear waveguide is revealed.

TM-mode selective filter using a high refractive index lossy layer cladded optical waveguide

This report describes a TM-mode selective filter with GaAlAs-optical waveguides for use in monolithic integrated optics. It has only a high refractive index lossy layer as a cladding layer. As the result of a computation of the eigenvalue equation for a comparatively simple structure, it was found that a TM-mode selective-filter action could be obtained through a proper choice of the material and thickness of the cladding layer.

Keynote address VII possibility of utilization of evanescent surface-wave for optical interconnection thin hollow cylinderical fiber held in air

Summary form only given. To explore the possibility of utilizing the evanescent surface wave propagating on fibers held in air for the purpose of realizing a fiber structure suited for the high bit-rate optical interconnection, a hollow-core cylindrical thin fiber contains no periodic structure within it is examined numerically. It is shown that the fiber having a group velocity close to the vacuum light speed and a relatively low valued GVD can be realized.

Optical Waveguide in GaAs by Drive-in Diffusion Technique

This report describes a technique for forming a thin layer as an optical waveguide in GaAs by a diffusion process alone. The optical waveguide has been fabricated by drive-in diffusion technique using powder-like ZnAs2 as the predeposition source. Since low-surface hole concentration and abrupt step profile are obtained therewith, this technique promises the possibility of forming low-loss waveguides for integrated optics through a comparatively simple process.