A technique is described for the simultaneous measurement of the difference in the normal components of strain and of the shear strain in luminescent III-V material from the degree of polarization (DOP) of photoluminescence. This technique for the measurement of shear strain and of the difference in the normal components of strain in InP was calibrated by applying known external loads on the bars of InP with V grooves etched into the bars and by fitting the experimental results to two-dimensional finite-element simulations. Fits to the difference in the normal components of strain (as opposed to stress) yielded significantly smaller residues. On this basis we conclude that the DOP of luminescence is proportional to the difference in the normal components of strain.

The residual strain fields resulting from laser micromachining of grooves in indium phosphide with femtosecond and nanosecond light pulses are analyzed using a spatially resolved degree-of-polarization photoluminescence technique. Significant differences in the geometry of the strain patterns are observed in grooves machined by femtosecond and nanosecond pulses. For the specific conditions investigated, the sign of the degree of polarization signal is opposite in the two cases indicating that areas under tension in femtosecond machined samples are under compression in nanosecond machined samples and visa versa. The experimental data are compared with results from a finite element model.

In this paper we report a novel fabrication technique for silicon photonic waveguides with sub-micron dimensions. The technique is based upon the Local Oxidation of Silicon (LOCOS) process widely utilised in the fabrication of microelectronics components. This approach enables waveguides to be fabricated with oxide sidewalls with minimal roughness at the silicon/SiO2 interface. It is also sufficiently flexible to enable the depth of the oxidised sidewall to be varied to control the polarisation performance of the waveguides. We will present preliminary results on submicron waveguide fabrication and loss characteristics (less than 1 dB/cm), as well as effects of varying waveguide width on modal properties of the waveguides. We consider the ease of fabrication, as well as the quality of the devices produced in preliminary experimental fabrication results, and compare the approach to the more conventional requirements of high resolution photolithographically produced waveguides. We also discuss preliminary optical results, as measured by conventional means. Issues such as the origins of loss are discussed in general terms, as are the fabrication characteristics such as waveguide wall roughness and waveguide profile. We will discuss further work that will help to establish the potential of the technique for future applications

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