Abstract: A WDM transmitter comprising an array of M pump lasers multiplexed by an M×N multiplexer, in the form of a coupler, and used to feed an array of N optically pumped fiber lasers emitting at wavelengths ?1, ?2, . . . ?N. The parameter M determines the number of pump lasers as well as the number of inputs of the pump-multiplexing coupler and can be smaller or equal to parameter N that determines the number of optically pumped lasers. The fiber laser outputs are passed through N isolators before entering N modulators were the signals are monolithically modulated. The outputs of the modulators are passed through an array of N tunable attenuators. Finally all the individual channel outputs are recombined into a single output in a combiner. The output will typically lead to an optical network. The proposed architecture may also be used for optical amplifiers, especially fiber-based optical amplifiers.

Abstract: A method of fabricating a band-processing optical fibre filter having a center wavelength &lgr;0′, the method comprises (i) radius-reducing a mismatched multi-core optical fibre having a core phase matching wavelength (before radius reduction) of &lgr;0 and a radius (before radius reduction) of a0, to a reduced radius Ra0, where R=&lgr;0′/&lgr;0; and (ii) providing light input and output connections to a section of the radius-reduced multi-core fibre so that input light is launched into one of the cores of the multi-core fibre section and output light emerges from one of the cores of the multi-core fibre section.

Abstract: A method of optical pulse propagation via a dispersive optical fibre, the method comprising the steps of: launching the optical pulses into the fibre at a pulse intensity sufficient to provide non-linear dispersion compensation during propagation through a first portion of the fibre; and providing a counter-chirping device to substantially compensate for the dispersion of a remaining, second portion of the fibre.

Abstract: A WDM transmitter comprising an array of M pump lasers multiplexed by an M×N multiplexer, in the form of a coupler, and used to feed an array of N optically pumped fiber lasers emitting at wavelengths &lgr;1, &lgr;2, . . . &lgr;N. The parameter M determines the number of pump lasers as well as the number of inputs of the pump-multiplexing coupler and can be smaller or equal to parameter N that determines the number of optically pumped lasers. The fiber laser outputs are passed through N isolators before entering N modulators were the signals are monolithically modulated. The outputs of the modulators are passed through an array of N tunable attenuators. Finally all the individual channel outputs are recombined into a single output in a combiner. The output will typically lead to an optical network. The proposed architecture may also be used for optical amplifiers, especially fiber-based optical amplifiers.

Abstract: A method of an apparatus for compensating optical non-linearity in optical devices and transmission systems. Two second order interactions are cascaded in phase-mismatched second harmonic generation to accumulate a non-linear phase shift of a fundamental wave. The non-linear phase shift can be set to provide a desired amount of non-linearity compensation. Compensation takes place in a compensating medium having a negative effective non-linear refractive index at the design operating conditions of the compensating medium. Compensators incorporating these principles may be incorporated as passive or active components in optical transmitters, repeaters or receivers. Active components may be tuned by varying the operating condition of the compensating medium, for example by controlling temperature or applied stress.

Abstract: Neodymium-doped fluoroaluminate optical glass has a composition: 35 to 45 mol % AlF3; 5 to 30 mol % RF2, where R is selected from the group consisting of Ca, Mg, Sr and Ba; 5 to 25 mol % MF, where M is selected from the group consisting of Na, Li, K and Rb; and 0.001 to 10 mol % dopant.

Abstract: A method of optical pulse propagation via a dispersive optical fibre, the method comprising the steps of: launching the optical pulses into the fibre at a pulse intensity sufficient to provide non-linear dispersion compensation during propagation through a first portion of the fibre; and providing a counter-chirping device to substantially compensate for the dispersion of a remaining, second portion of the fibre.

Abstract: An optical fibre amplifier, laser or superluminescent source, consisting of a chalcogenide glass matrix hosting trivalent rare earth ions and which is doped with oxide in the form of a metallic oxide. The device utilizes the properties of the added oxide to improve the fabrication and efficiency of optical waveguide sources, in particular for applications around 1.3 &mgr;m. Specifically, the oxide broadens the wavelength range for pump absorption, broadens the wavelength range for light emission, increases the device efficiency through a change in lifetime of certain laser levels and modifies properties of the glass to prevent crystallization during fiber fabrication. The device exploits the intentional addition of oxide to improve amplifier, laser, glass and fiber properties.

Abstract: Tin-doped photosensitive optical glass is disclosed, together with applications of the glass in fabricating waveguides and waveguide devices such as Bragg gratings.

Abstract: An optical fiber comprises a glass core having a core refractive index; a glass primary cladding at least partially surrounding said core, said primary cladding having a primary cladding refractive index lower than said core refractive index; a glass secondary cladding at least partially surrounding said primary cladding, said secondary cladding having a secondary cladding refractive index lower than said core refractive index but higher than said primary cladding refractive index; said glass of said core and said glass of at least part of said primary cladding containing one or more photosensitizing dopants.

Abstract: The core of a low phonon energy glass optical fibre is doped with trivalent Dysprosium ions for application as an efficient optical fibre amplifier operating around 1.3 .mu.m. The device utilises the transition .sup.6 H.sub.9/2 -.sup.6 F.sub.11/2 to .sup.6 H.sub.15/2. The low phonon energy (high quantum efficiency) glasses include mixed halides, chalcogenides and chalcohalides. Improvements in efficiency can be achieved by co-doping of the fibre core with Eu.sup.3+ and/or Tb.sup.3+ ions.

Abstract: An optical fiber has a cladding glass layer surrounding a glass core, in which a region (preferably annular) of the optical fiber partially overlapping the cladding and/or the core is formed of photosensitive glass.

Abstract: An optical fibre distributed feedback laser comprises an amplifying optical fibre (50) operable to provide optical gain at a lasing wavelength, in which a diffraction grating (30) is disposed on at least a portion of the amplifying optical fibre to provide distributed optical feedback for sustaining lasing action at the lasing wavelength.