Abstract: An optical device having a photonic band gap element operative such that the refractive index can be varied through application of an electrical signal. This enables the manufacture of tuneable lasers, optical add/drop multiplexers and tuneable optical wavelength converters.

Abstract: Controlling or stabilising the lasing wavelength of a source of laser radiation, wherein the source of laser radiation comprises a semiconductor material laser, a substrate to which the laser is mounted, a resonant optical cavity within the semiconductor material, the cavity having an active medium for generating laser radiation and one or more gaps in the semiconductor material within the cavity, wherein the substrate is deformable by the application of a mechanical stress to vary the size of the gap(s) in order to change the optical size of the gap(s) and hence to vary the wavelength of laser radiation generated by the semiconductor laser.

Abstract: A modulator assembly for modulation of light, for use as part of an opto-electronic communication network, has a light modulator assembly comprising a modulator element comprising a modulating medium for modulating the intensity of light passing therethrough. A single electrode applies an electric field across the modulating medium and heats the medium. The medium has an absorption edge at a wavelength dependent on the temperature of the medium and the applied electric field. The electrode heats the modulating medium such that the wavelength of the absorption edge aligns with the wavelength of the light to be modulated.

Abstract: The present invention relates to the control or stabilisation of the lasing wavelength of a source of laser radiation (8), comprising a semiconductor material laser (2), a substrate (4) to which the laser (2) is mounted, a resonant optical cavity (15) within the semiconductor material (16,18,20), the cavity (15) having an active medium (16) for generating laser radiation (8) and one or more gaps (28) in the semiconductor material (16,18,20) within the cavity (15), wherein the substrate (4) is deformable by the application of a mechanical stress (14) to vary the size of said gap(s) (28) in order to change the optical size of said gap(s) and hence to vary the wavelength of laser radiation (8) generated by the semiconductor laser (2).

Abstract: The present invention relates to a modulated light source, in particular for use as part of an opto-electronic communication network. The modulated light source has a laser and an external electro-optic modulator for modulating the intensity of light produced by the laser. A temperature sensor senses the temperature of the laser and the modulator. A control circuit connected to the temperature sensor adjusts the bias on the modulator so that the band edge of the modulator follows the changes in wavelength of the laser as the laser warms up during operation. This avoids the need for a cooling element to keep the temperature of the laser constant.

Abstract: An optical device comprising a photonic band gap element operative such that the refractive index can be varied through application of an electrical signal. This enables the manufacture of tuneable lasers, optical add/drop multiplexers and tuneable optical wavelength converters.

Abstract: This invention relates to a modulator assembly for modulation of light, in particular for use as part of an opto-electronic communication network. The invention provides a light modulator assembly comprising a modulator element comprising a modulating medium, for modulating the intensity of light passing therethrough; and means for applying an electric field across the modulating medium, the modulating medium having an absorption edge at a wavelength dependent upon the temperature of the medium and upon the applied electric field; and means for heating the modulating medium such that the wavelength of the absorption edge aligns with the wavelength of the light to be modulated.

Abstract: The present invention relates to a modulated light source (10), in particular for use as part of an opto-electronic communication network. The modulated light source (10) has a laser (12) and an external electro-optic modulator (16) for modulating the intensity of light produced by the laser (12). A temperature sensor (30) senses the temperature of the laser (12) and the modulator (16). A control circuit connected to the temperature sensor (30) adjusts the bias on the modulator (16) so that the band edge of the modulator follows the changes in wavelength of the laser (12) as the laser (12) warms up during operation. This avoids the need for a cooling element to keep the temperature of the laser (12) constant.