A microstructured optical fiber for generating supercontinuum light. The optical fiber includes a core and a cladding region surrounding the core. The optical fiber includes a first fiber length section, a second fiber length section as well as an intermediate fiber length section between said first and second fiber length sections. The first fiber length section has a core with a first characteristic core diameter larger than about 7 μm. The second fiber length section has a core with a second characteristic core diameter, smaller than said first characteristic core diameter. The intermediate length section of the optical fiber includes a core which is tapered from said first characteristic core diameter to the second characteristic core diameter over a tapered length. Also, a supercontinuum light source including an optical fiber and a pump light source.

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 T.sub.h, wherein Th is at least about 50° C., preferably 50° C.<Th.sub.h<250° C.

Disclosed by the present invention is an ultra-wideband white noise source based on a slicing super-continuum spectrum. The entropy source used is a super-continuum spectrum photon entropy source having a coverage range of several hundreds of nm, white noise can thus be generated in a wide frequency range, thereby effectively avoiding the bandwidth bottleneck of an electronic device. By separately adjusting the filter centers of two optical filters, the center frequency for generating the white noise can be adjusted so as to get adapted to different working situations. High bandwidth white noise can be generated by simply filtering the super-continuum spectrum and performing photoelectric conversion, and in comparison with the previous solutions, the solution of the present invention is simpler and can be easily implemented.

Improved efficiency for nonlinear optical interactions is provided by using strongly confining waveguides for simultaneous imposition of dispersion design constraints at two or more dispersion orders. Quasi-phase-matching allows for phase-matching to be accomplished independently of the waveguide design, which helps provide sufficient design freedom for the dispersion design.

A nonlinear element provides a nonlinear effect to light output from a pulsed laser source. Remaining light component having the oscillation wavelength of the pulsed laser source is attenuated when the light is split by a dichroic mirror. The divided light is subjected to pulse stretching by a fiber, and is combined by a multiplexing element. The light thus combined is irradiated to a target object S. The light transmitted through the target object S is received by a photoreceiver. The output signal of the photoreceiver is converted by a calculation unit into a spectrum.

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 T.sub.h, wherein T.sub.h is at least about 50° C., preferably 50° C.<T.sub.h<250° C.

[Object] An optimal structure for spectroscopically analyzing a solid-phase or liquid-phase sample in a wavelength range of 1100 to 1200 nm by using supercontinuum light is provided. [Solution] Supercontinuum light generated by producing nonlinear effects in light from a pulse laser source 1 by a nonlinear element 2 and having a wavelength range including 1100 nm or greater and 1200 nm or less is subjected to pulse stretching by a pulse stretching element 3, and a solid-phase or a liquid-phase sample S is irradiated with the supercontinuum light. In the supercontinuum light, elapsed time and wavelength within one pulse are in a one-to-one correspondence, and computation means 5 computes a spectrum based on a change over time in an output from a light receiver 4 that has received light that has passed through the sample S.

Improved efficiency for nonlinear optical interactions is provided by using strongly confining waveguides for simultaneous imposition of dispersion design constraints at two or more dispersion orders. Quasi-phase-matching allows for phase-matching to be accomplished independently of the waveguide design, which helps provide sufficient design freedom for the dispersion design.

A low wavelength infrared Super Continuum (SC) signal from a master oscillator introduces two or more seeds into an amplifier that supports the Raman effect. A counter-propagating, high-power, continuous wave, or quasi-continuous wave quantum cascade lasers pump (amplifies) a first optical seed creating a cascading amplification of subsequent optical seeds forming two or more tunable wavelength coherent optical pump sources.

A wavelength multiplexing system is presented comprising at least one basic functional unit extending between input and output light ports. The basic functional unit comprises at least one multi-core fiber. The multi-core fiber comprises N cores configured for supporting transmission of N wavelength channels λ.sub.1, . . . , λ.sub.n, wherein each of said at least one multi-core fibers is configured to apply a predetermined encoding pattern to the wavelength channels enabling linear mixing between them while propagating through multiple cores of said multi-core fiber. The encoding pattern may be configured to affect light propagation paths in the cores by inducing a predetermined dispersion pattern causing linear interaction and mixing between the channels; or may be configured to affect spectral encoding of the channels being transmitted through the cores by applying different weights to the channels.