Spi Lasers UK Limited

University of Southampton

Pirelli Cavi E Sistemi S.p.a.

Trumpf Laser Gmbh

Southampton Photonics Limited

Spl Lasers UK Limited

Michael Kevan Durkin

Morten Ibsen

Michael Nickolaos Zervas

Anatoly Borisovich Grudinin

Lars Johan Albinsson Nilsson

Paul William Turner

Dave Neil Payne

Mikhail Nickolaos Zervas

Richard Ian Laming

David Neil Payne

Malcolm Paul Varnham

Christophe Andre Codemard

Valeria Gusmeroli

Paulo Almeida

Mikhail Nicholaos Zervas

Fabio Ghiringhelli

Jayanta Kumar Sahu

Stephen Roy Norman

Louise Mary Brendan Hickey

Ricardo Feced

Andrew Michael Gillooly

Andy Piper

Stewart Thomas Ingram

Sebastien Georges Desmoulins

Anatoly Borisovich Grundinin

Motoren Ibsen

Apparatus for providing optical radiation (), which apparatus comprises an optical input (), a coupler (), a first semiconductor amplifier (), a controller (), a preamplifier (), a power amplifier () and an output fibre (), wherein: the optical input () is for receiving input optical radiation (); the optical input () is connected in series to the coupler (), the first semiconductor amplifier (), the preamplifier (), the power amplifier (), and the output fibre (); the apparatus being characterized in that: the first semiconductor amplifier () comprises a waveguide () having a low reflecting facet (); the first semiconductor amplifier () is in a double pass configuration such that the low reflecting facet () is connected to both the optical input () and the preamplifier () via the coupler (); and the controller () is configured to cause the waveguide () of the first semiconductor amplifier () to operate in saturation thereby enabling the first semiconductor amplifier () to reduce non-linear effects in the preamplifier (), the power amplifier (), and the output fibre ().

Apparatus for providing optical radiation

Apparatus for optical isolation, which apparatus comprises a laser (), a beam delivery system (), and an output port (), wherein: the beam delivery system () comprises an optical isolator () and an optical fibre (); the laser () is defined by a peak power (); the laser () emits laser radiation () at a signal wavelength (); the laser radiation () is coupled from the laser () to the output port () via the beam delivery system (); and the optical fibre () comprises an optical waveguide () defined by a core (), a cladding (), a mode field area () at the signal wavelength (), a length (), and a Raman wavelength (); and the apparatus being characterised in that: the Raman wavelength () is longer than the signal wavelength (); the beam delivery system () attenuates the laser radiation () at the signal wavelength () such that the power of the laser radiation () emitted by the laser () is more than the power of the laser radiation () at the output port (); the apparatus does not include a pump for pumping the laser radiation () at the signal wavelength () as the laser radiation () propagates along the optical fibre (); the optical isolator () has greater backward optical isolation () and greater forward transmission () at the signal wavelength () compared to the Raman wavelength (); and the optical fibre () comprises a suppressing means () for suppressing stimulated Raman scattering.

Apparatus and method for optical isolation

An optical amplifier includes at least one pump source and an optical fiber cable which includes an amplifying optical fiber and a pump optical fiber that are defined by respective lengths. The amplifying optical fiber and the pump optical fiber are coated with a common coating along a portion of their respective lengths, and the fibers are in optical contact with each other along a coating length within the common coating. The common coating has a refractive index which is lower than a refractive index of a cladding material of the pump optical fiber. The fibers are made substantially from glass. The amplifying optical fiber includes a core and a cladding, and is doped with a rare earth dopant. The pump optical fiber is defined by a first end and a second end, the first end of the pump optical fiber being connected to the pump source.

Multi-fibre arrangement for high power fibre lasers and amplifiers

Laser apparatus () comprising a reference source (), a reference fiber (), and at least one laser diode (), wherein the reference fiber () comprises a core () having a refractive index nand a first cladding () having a refractive index n, the first cladding () is surrounded by a second cladding () having a refractive index n, the refractive index nis greater than the refractive index n, the refractive index nis greater than the refractive index n, the laser diode () emits laser radiation () that is guided through the first cladding () of the reference fiber (), the reference source () emits reference radiation () that has a predetermined wavelength &#x3bb;(), the reference radiation () is guided through the core () of the reference fiber () to the laser diode (), and the reference radiation () that is guided through the core () of the reference fiber () to the laser diode () has a power () at the predetermined wavelength &#x3bb;(), which power is greater than an injection locking threshold of the laser diode.

Laser apparatus

An optical fiber arrangement has at least two optical fiber sections, each optical fiber section defining an outside longitudinally extending surface. The outside longitudinally extending surfaces are in optical contact with each other. The invention further provides for an amplifying optical device have an optical fiber arrangement as just described, and a pump source. The amplifying optical device is configured such that the pump source illuminates the amplifying optical fiber. A amplifying arrangement is also disclosed. The amplifying arrangement includes a plurality of amplifying optical devices as just described, and each amplifier also has at least one input fiber and a first multiplexer connected to the input fiber. Each amplifier is configured such that at least one of the amplifying optical fibers is connected to the first multiplexer. The amplifying arrangement also has a second multiplexer connected to each of the first multiplexers.

In one embodiment, a photo-darkening resistant optical fiber includes a waveguide having a numerical aperture less than 0.15. The waveguide includes a core having a refractive index nand a pedestal having a refractive index n, and wherein the fiber includes a first cladding having a refractive index nsurrounding the pedestal, wherein nis greater than n, nis greater than n. The core includes silica, a concentration of alumina of between approximately 0.3 to 0.8 mole percent, a concentration of phosphate of substantially 15 mole percent, a concentration of ytterbium substantially in the range 20000 to 45000 ppm. The pedestal can include silica, phosphate and germania. The core can have substantially zero thulium dopant.

Apparatus for filtering optical radiation at an operating wavelength (), which apparatus comprises a grating () written into a waveguide (), and which grating () has a first end (), a second end (), a first bandwidth (), a maximum re-flectivity (), a first group delay variation () defined with respect to the first end (), and a second group delay variation () defined with respect to the second end (), wherein the first and second group delay variations (), () are with respect to the first bandwidth (), the maximum reflectivity () is greater than 50%, the first group delay variation () is between 0.1 ps and 100 ps, and the second group delay variation () is between 0.1 ps and 100 ps.

Apparatus for filtering optical radiation at an operating wavelength

An optical fibre arrangement has at least two optical fibre sections, each optical fibre section defining an outside longitudinally extending surface. The outside longitudinally extending surfaces are in optical contact with each other. The invention further provides for an amplifying optical device have an optical fibre arrangement as just described, and a pump source. The amplifying optical device is configured such that the pump source illuminates the amplifying optical fibre. A amplifying arrangement is also disclosed. The amplifying arrangement includes a plurality of amplifying optical devices as just described, and each amplifier also has at least one input fibre and a first multiplexer connected to the input fibre. Each amplifier is configured such that at least one of the amplifying optical fibres is connected to the first multiplexer. The amplifying arrangement also has a second multiplexer connected to each of the first multiplexers.

Multi-fibre arrangements for high power fibre lasers and amplifiers

An optical waveguide grating if formed in a waveguide of nominally uniform diameter. A grating characteristic is varied at positions along the grating in a substantially inverse relationship to the diameter of the waveguide at those positions.

Fabricating optical waveguide gratings and/or characterising optical waveguides

Methods and apparatus for creating a Bragg grating in an optical waveguide having an optical fiber on which the Bragg grating is defined, the Bragg grating having an actual response which closely approximates a desired response. The Bragg grating comprises a plurality of lines, each line being defined by a respective strength, and each line having a relative displacement from adjacent lines. The Bragg grating is designed using a serial iterative response. The serial iterative process can be used to calculate the strength and the line spacing of at least some of the lines. The serial iterative process can further be a function of a coupling function, which is a function of the strength and line spacing of the lines of the grating. A moving window can be used to limit the number of reflections in the impulse response which is used to calculate the next serial line spacing. The serial iterative process can further be a function of the group velocity of light in the optical fiber, the reflectivity of the grating, and the dispersion response of the grating.

Optical fiber grating

A method of fabricating a chirped optical fibre grating so that the grating has a predetermined desired wavelength-dependent response across an operational bandwidth comprises apodising the grating so that a degree of apodisation at a longitudinal position along the grating corresponds to the desired response at the optical wavelength reflected at that longitudinal position along the grating.

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Worcestershire, United Kingdom

Michael Kevan Durkin