Abstract: An optical fiber having an axial direction and a cross section perpendicular to the axial direction, and a method and preform for producing such an optical fiber. The optical fiber is adapted to guide light at a wavelength ?, and includes a core region, an inner cladding region surrounding said core region, and at least one of a first type of feature including a void and a surrounding first silica material. The core, the inner cladding region and the first type of feature extends along said axial direction over at least a part of the length of the optical fiber. The first silica material has a first chlorine concentration of about 300 ppm or less.

Abstract: A wavelength-stabilised narrow-linewidth mode-locked picosecond laser system comprises a laser cavity which includes an amplifier, a mode-locking element, and a fiber Bragg grating which acts as a narrowband reflector. The system includes a mount to which the fiber Bragg grating is mounted under tension, a tension control system to adjust the tension, and a measurement device to provide a measurement output related to a current operating wavelength of the fiber Bragg grating. A microcontroller or other controller wavelength-stabilises the laser by controlling the tension control system responsive to the measured wavelength.

Abstract: A method of making a microstructured optical fiber including loading the core and cladding materials of the fiber with hydrogen and deuterium at a loading temperature; annealing the fiber at a selected temperature Tanneal; pumping the fiber with radiation; and reducing the temperature of the fiber and storing the fiber at the reduced temperature before the step of pumping the fiber; and wherein the method allows the hydrogen and the deuterium to become bound to the core material and the cladding material.

Abstract: A laser device includes a laser configured to generate laser light and a laser control module configured to receive at least a portion of the laser light generated by the laser, to generate a control signal and to feed the control signal back to the laser for stabilizing the frequency, wherein the laser control module includes a tunable frequency discriminating element which is preferably continuously frequency tunable, and where the laser control module is placed outside the laser cavity.

Abstract: A light source including: a pulse generator for providing a first sequence of light pulses, the first sequence of light pulses including a first number of light pulses within a predetermined time period, a manipulator configured to generate a second sequence of light pulses from the first sequence of light pulses, the second sequence of light pulses having a second number of light pulses within the predetermined time period, the second number being different from the first number, and a nonlinear optical element arranged to receive the second sequence of light pulses.

Abstract: A Photonic Crystal Fiber (PCF) a method of its production and a supercontinuum light source comprising such PCF. The PCF has a longitudinal axis and includes a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region includes a plurality of microstructures in the form of inclusions extending along the longitudinal axis of the PCF in at least a microstructured length section. In at least a degradation resistant length section of the microstructured length section the PCF includes hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further includes a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below Th, wherein Th is at least about 50° C., preferably 50° C.<Th<250° C.

Abstract: A supercontinuum source including a pump source and a supercontinuum generator configured for receiving electromagnetic radiation derived from the pump source and for generating supercontinuum radiation, the supercontinuum generator including a nonlinear microstructured optical fibre having a core region comprising silica. The core region includes a dopant selected to reduce light-induced non-bridging oxygen hole centre loss in the nonlinear microstructured optical fibre.

Abstract: An optical source (100) comprising a supercontinuum generation apparatus comprising a pump light source (102), a twisted photonic crystal fibre, PCF, (104) and a wideband quarter-wave retarder (106). The pump light source is arranged to provide circularly polarised pump light. The twisted PCF is arranged to receive the pump light and to convert the pump light into circularly polarised supercontinuum light. The wideband quarter-wave retarder is arranged to convert the circularly polarised supercontinuum light into linearly polarised supercontinuum light. The optical source may additionally comprise a wavelength tunable bandpass optical filter arranged to transmit the linearly polarised supercontinuum light at wavelengths within a selected range.

Abstract: A light source including: a pulse generator for providing a first sequence of light pulses, the first sequence of light pulses including a first number of light pulses within a predetermined time period, a manipulator configured to generate a second sequence of light pulses from the first sequence of light pulses, the second sequence of light pulses having a second number of light pulses within the predetermined time period, the second number being different from the first number, and a nonlinear optical element arranged to receive the second sequence of light pulses.

Abstract: A filter for filtering a broadband beam and in one embodiment a fluorescence measurement system comprising such a filter. The system includes a broadband light source arranged to provide a broadband beam, a first tunable element arranged to filter at least a portion of the broadband beam thereby providing filtered light and a control unit arranged to provide a control signal to the first tunable element. In one embodiment the first tunable element is an acousto-optic filter (AOTF) and the control signal to the AOTF is an acoustic RF signal provided by a Voltage Controlled Oscillator (VCO) arranged so the AOTF provide a high out-of-band suppression.

Abstract: A supercontinuum light source can include a seed laser arranged to provide seed pulses with a pulse frequency Fseed; a pulse frequency multiplier (PFM) arranged to multiply the seed pulses by converting pulses having the pulse frequency Fseed to pump pulses with a pulse frequency Fpump, where Fpump is larger than Fseed; and a non-linear element arranged to receive said pump pulses and convert said pump pulses to pulses of supercontinuum light. The PFM can further include a splitter for splitting pulses into first and second sub beams each having the same pulse frequency, where the PFM is configured such that the sub beams experience different delays; and a combiner for combining said first and second sub beams into a beam having the pulse frequency that is greater than said same pulse frequency. The splitter can have an uneven splitter ratio.

Abstract: A Photonic Crystal Fiber (PCF) a method of its production and a supercontinuum light source comprising such PCF. The PCF has a longitudinal axis and includes a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region includes a plurality of microstructures in the form of inclusions extending along the longitudinal axis of the PCF in at least a microstructured length section. In at least a degradation resistant length section of the microstructured length section the PCF includes hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further includes a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below Th, wherein Th is at least about 50° C., preferably 50° C.<Th<250° C.

Abstract: A light source including: a pulse generator for providing an initial sequence of light pulses, the pulse generator including an optical source for producing optical pulses; a modulator in communication with the optical source for increasing or decreasing the selected number of pulses provided by the pulse generator in the selected time period; first and second optical arms, for propagating, respectively, first and second sequences of light pulses, wherein the first optical arm includes a first manipulator configured to generate the first sequence of light pulses from the initial sequence of light pulses, wherein the light source includes a nonlinear optical element arranged to receive the first sequence of light pulses or the second sequence of light pulses, and an optical switch arranged to switch either the first sequence of light pulses or the second sequence of light pulses for reception by the nonlinear optical element.

Abstract: A supercontinuum source including a pump source and a supercontinuum generator configured for receiving electromagnetic radiation derived from the pump source and for generating supercontinuum radiation, the supercontinuum generator including a nonlinear microstructured optical fibre having a core region comprising silica. The core region includes a dopant selected to reduce light-induced non-bridging oxygen hole centre loss in the nonlinear microstructured optical fibre.

Abstract: A photonic crystal fiber (PCF) assembly including a PCF and at least one ferrule structure. The PCF includes a core region and a cladding region and a first fiber end section with a first fiber end. The ferrule structure is mounted to the first fiber end section. The ferrule structure includes an inner ferrule arrangement and an outer ferrule arrangement surrounding the first fiber end section. The inner ferrule arrangement includes an inner ferrule front section proximally to the first fiber end and an inner ferrule rear section distally to the first fiber end, and each of the sections has an inner diameter and in at least a length thereof fully surrounds the PCF. The inner ferrule rear section is anchored in an anchor length section to the first fiber end section and the inner ferrule front section supports the first fiber end section proximally to the first fiber end.

Abstract: A method of producing a microstructured optical fiber is disclosed. The method includes providing a preform and drawing the preform. The preform has a center axis, a length and a first end and a second end and has at least one longitudinal hole extending lengthwise. The method includes inserting a first end of a pressure tube into the hole of the preform at the first end of the preform and subjecting the hole of the preform to a controlled pressure via the pressure tube during the drawing.

Abstract: An optical fiber having an axial direction and a cross section perpendicular to the axial direction, and a method and preform for producing such an optical fiber. The optical fiber is adapted to guide light at a wavelength ?, and includes a core region, an inner cladding region surrounding said core region, and at least one of a first type of feature including a void and a surrounding first silica material. The core, the inner cladding region and the first type of feature extends along said axial direction over at least a part of the length of the optical fiber. The first silica material has a first chlorine concentration of about 300 ppm or less.

Abstract: A preform element, its production, and fiber production methods from preform assemblies. The preform element has a length and a center axis along its length, a first and second end defined by its length and an outer preform element surface. The preform element includes a plurality of longitudinal structures disposed to form longitudinal hole(s) in a background material. At least one slot extending from its outer preform element surface and intersecting at least one of the longitudinal holes, wherein the at least one slot does not fully intersect the preform element. The preform element may be a preform center element or a preform ring element and may be assembled to a form part of a preform assembly for an optical fiber.

Abstract: A light source including: a pulse generator for providing a first sequence of light pulses, the first sequence of light pulses including a first number of light pulses within a predetermined time period, a manipulator configured to generate a second sequence of light pulses from the first sequence of light pulses, the second sequence of light pulses having a second number of light pulses within the predetermined time period, the second number being different from the first number, and a nonlinear optical element arranged to receive the second sequence of light pulses.

Abstract: A supercontinuum light source includes a microstructured optical fiber, and a feeding unit arranged for feeding pump pulses to the microstructured optical fiber, wherein the feeding unit comprises a picosecond laser and one or more amplifiers, wherein the microstructured optical fiber is a silica fiber wherein at least a part of the core being of silica or doped silica, and including a core including core material and a cladding surrounding the core, and at least the core material is loaded with deuterium to have an OD absorption peak around 1870 nm, wherein the feeding unit is spliced to the microstructured optical fiber.