Abstract: An optical waveguide adapter assembly comprises a solid core optical waveguide extending between a free end and a coupled end and having a solid waveguiding core with an associated first optical mode field size; a hollow core optical waveguide extending between a free end and a coupled end and having a hollow waveguiding core with an associated second optical mode field size; and an optical mode field adapter extending between a first end and a second end and having a waveguiding core configured to change an optical mode field of a waveguided optical signal substantially between the first optical mode field size at the first end of the optical mode field adapter and the second optical mode field size at the second end of the optical mode field adapter, the first end of the optical mode field adapter joined to the coupled end of the solid core optical waveguide to provide optical coupling between the waveguiding core of the solid core optical waveguide and the waveguiding core of the optical mode field adapter

Abstract: An optical fibre assembly comprises a hollow core optical waveguide comprising a hollow core surrounded by a structured arrangement of longitudinally extending capillaries providing an inner cladding surrounded by an outer cladding; a diagnostic solid core optical waveguide comprising a solid core surrounded by a cladding, and extending substantially parallel to the hollow core optical waveguide; and a jacket surrounding both the hollow core optical waveguide and the solid core optical waveguide and forming a common mechanical environment for the hollow core optical waveguide and the solid core optical waveguide. The optical fibre assembly may be or may comprise or be included in an optical fibre cable, and may be used in a method for testing hollow core optical waveguides.

Abstract: An optical fibre assembly comprises a hollow core optical waveguide comprising a hollow core surrounded by a structured arrangement of longitudinally extending capillaries providing an inner cladding surrounded by an outer cladding; a diagnostic solid core optical waveguide comprising a solid core surrounded by a cladding, and extending substantially parallel to the hollow core optical waveguide; and a jacket surrounding both the hollow core optical waveguide and the solid core optical waveguide and forming a common mechanical environment for the hollow core optical waveguide and the solid core optical waveguide. The optical fibre assembly may be or may comprise or be included in an optical fibre cable, and may be used in a method for testing hollow core optical waveguides.

Abstract: A method of processing glass filament comprises: providing a length of glass filament from which a portion is to be separated from the remainder of the filament; directing energy onto the filament in order to cause a decrease in a width of the filament at a desired location for separation of the portion; and causing relative longitudinal movement between the portion and the remainder of the filament to separate the portion from the remainder of the filament at the desired location.

Abstract: An optical waveguide adapter assembly comprises a solid core optical waveguide extending between a free end and a coupled end and having a solid waveguiding core with an associated first optical mode field size; a hollow core optical waveguide extending between a free end and a coupled end and having a hollow waveguiding core with an associated second optical mode field size; and an optical mode field adapter extending between a first end and a second end and having a waveguiding core configured to change an optical mode field of a waveguided optical signal substantially between the first optical mode field size at the first end of the optical mode field adapter and the second optical mode field size at the second end of the optical mode field adapter, the first end of the optical mode field adapter joined to the coupled end of the solid core optical waveguide to provide optical coupling between the waveguiding core of the solid core optical waveguide and the waveguiding core of the optical mode field adapter

Abstract: An optical fibre assembly comprises a hollow core optical waveguide comprising a hollow core surrounded by a structured arrangement of longitudinally extending capillaries providing an inner cladding surrounded by an outer cladding; a diagnostic solid core optical waveguide comprising a solid core surrounded by a cladding, and extending substantially parallel to the hollow core optical waveguide; and a jacket surrounding both the hollow core optical waveguide and the solid core optical waveguide and forming a common mechanical environment for the hollow core optical waveguide and the solid core optical waveguide. The optical fibre assembly may be or may comprise or be included in an optical fibre cable, and may be used in a method for testing hollow core optical waveguides.

Abstract: Apparatus for combining laser radiation (1) 5 which apparatus comprises a seed laser (2), a splitter (3), a plurality of amplifier chains (4), a reference amplifier chain (7), detection means (5). demodulator means (6), and phase control means (12), wherein each of the amplifier chains (4) comprises at least one optical amplifier (11), optical radiation (17) emitted from the seed laser (2) is split into the plurality of amplifier chains (4) by the splitter (3).

Abstract: Apparatus for combining laser radiation (1) 5 which apparatus comprises a seed laser (2), a splitter (3), a plurality of amplifier chains (4), a reference amplifier chain (7), detection means (5). demodulator means (6), and phase control means (12), wherein each of the amplifier chains (4) comprises at least one optical amplifier (11), optical radiation (17) emitted from the seed laser (2) is split into the plurality of amplifier chains (4) by the splitter (3).

Abstract: A wavelength of an optical source is monitored by first and second adjacent detectors on a common base. A bulk reflective component has first and second partially reflective surfaces that respectively direct first and second portions of energy from the source to the first and second detectors. A wavelength discriminator is positioned between the first detector and first surface. An optical isolator downstream of the reflective component prevents radiation from the source and exiting the component from being coupled to the detectors and back to the source.

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: 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: A known configuration for detecting changes in wavelength of light from a laser device comprises a beam splitter for directing incident light thereupon towards a first photodiode via an optical filter and a second photodiode spaced relatively far apart from the first photodiode, thereby increasing an overall package size for the laser device in combination with a wavelength locker. The present invention overcomes this problem by disposing the first photodiode (114) adjacent the second photodiode (116) and employing an optical diffractive element (108) to direct, along distinct optical paths, light towards each of the first photodiode (114) and the second photodiode (116).

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: The invention relates to a method and a device for wavelength stabilisation of an optical source, particularly in Wavelength Division Multiplexing (WDM) systems. The device comprises a laser source (2), an interference filter (10), an array (14) of photodetectors (40,46), means (4) for controlling the wavelength of the laser, and a comparator (22). The interference filter (10) is illuminated (9) with optical radiation from the laser source (2) and projects a pattern of interference fringes (11) on the photodetector array (14). The pattern (11) changes according to the wavelength &lgr; of optical radiation received (9) by the interference filter (10). At least two of the photodetectors (40,44) are used to generate corresponding signals (20,30), each of said signals varying depending on the intensity of the interference fringes (11) at the corresponding photodetector (40,46).

Abstract: An optical device includes an optical waveguide with a block that is fusion spliced to one end. The block has a refractive index approximately equal to the effective refractive index of the waveguide and is of such a length that substantially all the light exiting the waveguide propagates directly to the end of the block remote from the waveguide.

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.

Abstract: Embodiments of the present invention provide optical fibre microlenses having anamorphic focusing means which have a major axis which is not perpendicular to the longitudinal axis of the optical fibre. In particular, a wedge-shaped optical fibre microlens whose tip is skewed with respect to the longitudinal axis of the optical fibre, is described. Such optical fibre microlenses find particular application in coupling light from semiconductor lasers having asymmetrical output radiation patterns, since they increase the coupling efficiency and reduce the level of back reflection from the microlens to the laser. This is of particular importance for semiconductor lasers used to pump optical fibre amplifiers.

Abstract: A packaged optical amplifier assembly includes an erbium doped silica based optical amplifying fiber (330) co-pumped and counter-pumped by a pair of laser diodes (336) as optical pumps. The optical pumps (336) are each coupled to an end (332, 340) of the fiber (330) by reflection from a dichroic mirror (328), the optical signal being collimated and arranged to propagate unguided between the input (306) and the first end (332), and the second end (340) and the output (346), and optical pump light from each optical pump (336) being collimated and arranged to propagate unguided between the optical pump (336) and the end of the fiber (332, 340) to which it is coupled.