Abstract: A frequency conversion device, including a source of a pump beam of electromagnetic radiation of a first wavelength, and an array of mutually spaced semiconductor islands including at least one III-V semiconductor compound and configured so that the pump beam of electromagnetic radiation of the first wavelength incident upon the semiconductor islands and electromagnetic radiation of a second wavelength incident upon the semiconductor islands cause the semiconductor islands to emit electromagnetic radiation of a third wavelength different to the first and second wavelengths by at least one of a sum frequency generation process and a difference frequency generation process, wherein the semiconductor islands are supported by a transparent support such that the support is substantially transparent to radiation of the third wavelength, wherein at least the radiation of the third wavelength passes through the transparent support.

Abstract: A frequency conversion device, including a source of a pump beam of electromagnetic radiation of a first wavelength, and an array of mutually spaced semiconductor islands composed of at least one III-V semiconductor compound and configured so that the pump beam of electromagnetic radiation of the first wavelength incident upon the semiconductor islands and electromagnetic radiation of a second wavelength incident upon the semiconductor islands cause the semiconductor islands to emit electromagnetic radiation of a third wavelength different to the first and second wavelengths by at least one of a sum frequency generation process and a difference frequency generation process; wherein the semiconductor islands are supported by a transparent support such that the support is substantially transparent to radiation of the third wavelength, wherein at least the radiation of the third wavelength passes through the transparent support.

Abstract: A frequency conversion device and method is disclosed. In one aspect, a frequency device includes an array of mutually spaced semiconductor islands composed of at least one III-V semiconductor compound. The semiconductor islands are configured so that electromagnetic radiation of a first wavelength incident upon the semiconductor islands causes them to emit electromagnetic radiation of a second wavelength shorter than the first wavelength by a nonlinear frequency conversion process. The frequency device further includes a transparent support supporting the semiconductor islands. The transparent support is substantially transparent to radiation of the second wavelength, so that at least the radiation of the second wavelength passes through the transparent support.

Abstract: A frequency conversion device and method is disclosed. In one aspect, a frequency device includes an array of mutually spaced semiconductor islands composed of at least one III-V semiconductor compound. The semiconductor islands are configured so that electromagnetic radiation of a first wavelength incident upon the semiconductor islands causes them to emit electromagnetic radiation of a second wavelength shorter than the first wavelength by a nonlinear frequency conversion process. The frequency device further includes a transparent support supporting the semiconductor islands. The transparent support is substantially transparent to radiation of the second wavelength, so that at least the radiation of the second wavelength passes through the transparent support.

Abstract: The present invention relates to the field of phase measurement, particularly optical phase measurement. In one form, the invention relates to a method and device for measuring the phase between distinct signals by converting phase variations between the signals into amplitude variations. In one embodiment the invention provides a method of arranging the structure of a two-dimensional or three-dimensional crystal to measure the phase between signals, comprising the steps of (i) providing a respective waveguide for each signal and (ii) providing a micro-cavity array arranged to provide a resonance output in response to the phase of the signals. The invention has application to a wide range of apparatus and devices across many industries including communications, food technology, pharmacology, medicine and biology.

Abstract: A single-mode optical device, including a first region, and a second region laterally disposed about the first region, and including an absorbing layer and an isolation layer between the absorbing layer and the first region, wherein the thickness of the isolation layer is selected to control optical loss from the first region to the absorbing layer in the second region and thereby to attenuate one or more high order lateral optical modes of the device. The one or more high order lateral optical modes are attenuated relative to the fundamental lateral mode to provide the device with a high kink power. The device can be a 980 nm ridge diode laser where the thickness of an oxide insulating layer around the ridge is selected to control optical losses into a gold contact layer and thereby attenuate the first order lateral mode, providing the laser with a kink power of at least about 250 mW.

Abstract: A diode laser having a plurality of layers including a thin (e.g., about 0.3 ?m or less) p-type cladding layer, the plurality of layers having a substantially asymmetric refractive index profile with respect to the layer growth direction to produce an optical field distribution with a larger fraction of the distribution in n-type layers than in p-type layers of the laser. The layers can be configured to produce a ridge diode laser having an internal loss less than about 3 cm?1, and able to generate an approximately 980 nm laser beam with a transverse divergence of about 28° or less, and a spot size of about 0.8 ?m or more.

Abstract: A method of disordering a quantum well heterostructure, including the step of irradiating the heterostructure with a particle beam, wherein the energy of the beam is such that the beam creates a substantially constant distribution of defects within the heterostructure. The irradiating particles can be ions or electrons, and the energy is preferably such that the irradiating particles pass through the heterostructure. Light ions such as hydrogen ions are preferred because they are readily available and produce substantially uniform distributions of point defects at relatively low energies. The method can be used to tune the wavelength range of an optoelectronic device including such a heterostructure, such as a photodetector.

Abstract: A diode laser formed by a plurality of layers including n-type layers and p-type layers, the plurality of layers having a substantially asymmetric refractive index profile with respect to the layer growth direction so as to generate an optical field distribution with a larger fraction in n-type layers than in p-type layers, and configured to generate a beam with a divergence of less than about 28° in the growth direction. The layers include an active layer for generating the optical field, a trap layer for attracting the optical field, and a separation layer between the active layer and the trap layer for repelling the optical field. The laser can be configured to have an internal loss of about 1.2 cm?1 or less, and to generate a laser beam with a spot size of at least about 1.1 ?m and a divergence of approximately 13° in the growth direction. If the length of the laser is at least about 1 mm, the threshold current density of the laser can be less than about 400 A cm?2.

Abstract: A diode laser having a plurality of layers including a thin (e.g., about 0.3 &mgr;m or less) p-type cladding layer, the plurality of layers having a substantially asymmetric refractive index profile with respect to the layer growth direction to produce an optical field distribution with a larger fraction of the distribution in n-type layers than in p-type layers of the laser. The layers can be configured to produce a ridge diode laser having an internal loss less than about 3 cm−1, and able to generate an approximately 980 nm laser beam with a transverse divergence of about 28° or less, and a spot size of about 0.8 &mgr;m or more.

Abstract: A single-mode optical device, including a first region, and a second region laterally disposed about the first region, and including an absorbing layer and an isolation layer between the absorbing layer and the first region, wherein the thickness of the isolation layer is selected to control optical loss from the first region to the absorbing layer in the second region and thereby to attenuate one or more high order lateral optical modes of the device. The one or more high order lateral optical modes are attenuated relative to the fundamental lateral mode to provide the device with a high kink power. The device can be a 980 nm ridge diode laser where the thickness of an oxide insulating layer around the ridge is selected to control optical losses into a gold contact layer and thereby attenuate the first order lateral mode, providing the laser with a kink power of at least about 250 mW.

Abstract: A diode laser formed by a plurality of layers including n-type layers and p-type layers, the plurality of layers having a substantially asymmetric refractive index profile with respect to the layer growth direction so as to generate an optical field distribution with a larger fraction in n-type layers than in p-type layers, and configured to generate a beam with a divergence of less than about 28° in the growth direction. The layers include an active layer for generating the optical field, a trap layer for attracting the optical field, and a separation layer between the active layer and the trap layer for repelling the optical field. The laser can be configured to have an internal loss of about 1.2 cm−1 or less, and to generate a laser beam with a spot size of at least about 1.1 &mgr;m and a divergence of approximately 13° in the growth direction. If the length of the laser is at least about 1 mm, the threshold current density of the laser can be less than about 400 A cm−2.