Slab-coupled Waveguide Research Articles

Robust slab-coupled buried-rib semiconductor laser with high fibre coupling efficiency

A robust, single transverse mode slab-coupled buried-rib waveguide laser by combining the concept of slab-coupled waveguide and the technique of diluted waveguide is demonstrated. The large mode size and near-circular mode profile result in high fibre coupling efficiency and improved alignment tolerance.

A real-index guided InGaAlP visible laser diode with a small beam astigmatism

A real-index guided InGaAlP visible laser diode with a small beam astigmatism has been developed. The structure, fabrication process, and optical properties of the laser are described. The laser is characterized by a slab-coupled waveguide structure with self-aligned current confinement. The laser was fabricated with a two-step metalorganic chemical vapor deposition (MOCVD) process. The laser exhibited stable fundamental transverse mode oscillation with a threshold current as low as 40 mA and a lasing wavelength of 670 nm. As a result of real-index guiding, a small beam astigmatism less than 2 mu m has been achieved. The laser exhibited a stable operation for 2000 h under 3 mW at 30 degrees C. >

Analysis of unbounded dielectric waveguides using the surface integral equations method

The surface integral equations method, capable of treating a guiding structure composed of bounded homogeneous dielectric cylinders, is generalised to treat unbounded (in a transverse plane) waveguides in integrated optics, such as the slab-coupled waveguide. The approximation made in the present method is to truncate associated infinite integrations. Justification of such a truncation is given.

Single-mode optical waveguides and phase modulators in the InP material system

The characteristics of several different single-mode optical waveguides in the InP material system are discussed. Slab-coupled rib waveguides in GaInAsP ( \lambda_{gap} \approx 1 \mu m) epitaxial layers grown on InP have shown propagation losses as low as 1.7 cm-1at 1.3 μm and 2.7 cm-1at 1.15 μm. Oxide-confined InP rib guides fabricated using a lateral overgrowth technique have losses of about 1.5 cm-1at 1.15 μm. Three-guide couplers have been made by fabricating three parallel oxide-confined guides in close proximity. InP p+-n-n+ guides capable of modulating TE-polarized radiation have been fabricated using epitaxial techniques and Be-ion implantation. By measuring the phase difference between the TE-like and TM-like modes as a function of applied voltage, an estimate of the r 41 electrooptic coefficient in InP at 1.3 μm that is in good agreement with a previously reported value was obtained. Guides of this type should find use as the active components in InP switches and interferometers.

Correction to "Analysis of the guided modes in slab-coupled waveguides using a variational method"

Correction to "Analysis of the guided modes in slab-coupled waveguides using a variational method"

Analysis of the guided modes in slab-coupled waveguides using a variational method

The waveguiding properties of the slab-coupled waveguides (i.e., the optical stripline and the rib waveguide) are investigated by the vector variational method. The slab-coupled waveguides are low-loss optical waveguides which are easy to fabricate and design. In this paper, the propagation constants and the field intensity distributions of the slab-coupled waveguides are presented, and the effects on the wave-guiding properties caused by changing their geometrical parameters are discussed. The results obtained by employing the variational method are compared with those obtained by using other methods.

A directional coupler with large waveguide separation

We discuss experimental results of a directional coupler, fabricated by ion implantation through a conventionally produced photoresist mask into fused quartz. The waveguides are 5 μm wide and separated by 5 μm. Though the separation is very large the coupling length is about 4 mm at λ = 676 nm. This can be explained by a special waveguide type similar to slab-coupled waveguides which causes a high field penetration of the guided wave into the surrounding. The dependence of the coupler on various technological parameters is given and the use as a frequency selective element is experimentally demonstrated.

Slab-Coupled Waveguides

The slab-coupled waveguide, consisting of a dielectric rod lying on a slab that in turn covers a substrate, is a multidielectric waveguide that includes such special cases as the single-material fiber, the rib waveguide, and the strip-loaded film guide. These guides have recently become known as potentially useful either for long-distance optical transmission or for integrated optics. Simple, closed-form, approximate solutions have been found to describe the following properties of the guide: number of modes, their field configurations and propagation constants, numerical aperture, requirements for single-mode operation, field penetration in the slab, tolerance to curvature of the guide axis, dispersion, and impulse response.