Abstract:
Disclosed is an optical array for generating a broadband spectrum. The aim of the invention is to reduce the technical complexity of said optical array while keeping the source of laser radiation compact and adjusting in a simple manner the wavelength range of the broadband spectrum to the sensitivity range of conventional semiconductor detectors. Said aim is achieved by coupling in an optically adapted manner a passively mode-coupled solid body laser which supplies picosecond impulses having an initial wavelength that lies within the infrared range to a photonic fiber. A radiation performance interval of the broadband spectrum, which is maintained at an essentially steady intensity, is set within a wavelength range of 700 nm to 1000 nm below the initial wavelength by adjusting the dispersion of said photonic fiber to the initial wavelength. The broadband source of radiation is highly brilliant and can be used in white light interferometry (OCT, coherence radar, spectral radar) and in spectroscopy (pump-probe spectroscopy), among others.
Abstract:
A method of thermally poling a silica based waveguide (12) comprises exposing a region of the waveguide (12) to an electric field (for example, via capillary electrodes (22, 24) inserted into holes in the waveguide); directing a laser beam (18) into the region exposed to the electric field to effect localized heating of the region via direct absorption; and scanning the laser beam (18) over the region at a rate selected to avoid heating of the region above the glass transition temperature. Reversing the electric field while scanning the laser beam (18) allows the formation of periodic poled gratings. The waveguide (12) can comprise an optical fiber.
Abstract:
In accordance with the invention there is provided an optical wavelength conversion device. The conversion device comprises a micro-structured optical waveguide, which includes sections with a non-linear material having an index of refraction which changes as a non-linear function of light intensity. The optical waveguide includes a light guiding core region, and the waveguide is dimensioned for providing spatial overlap between the sections filled with the non-linear material and light propagating within the waveguide. The conversion device further comprises a first optical light source for introducing light into the waveguide in a mode guided along the core, and a second intensity modulated light source for introducing encoding light into the waveguide in such a manner that it illuminates the sections filled with a non-linear material. The second light source has an intensity modulation sufficient to change the refractive index of the non-linear material by an amount sufficient to encode or modulate the light from the first optical light source accordingly, whereby the encoding takes place through the effect of leaking light from the first light source from the inside of the guiding core to the outside of the guiding core. The micro-structured optical waveguide may comprisean optical fibre, in which the light from the first light source may be guided by different types of waveguiding principles including total internal reflection or by photonic bandgap effects. In an alternative embodiment the micro-structured optical waveguide may comprise an optical planar waveguide. The conversion device includes embodiments in which the encoding light from the secondlight source and the light to be encoded or modulated from the first light source are co-propagating, are counter-propagating, or where the encoding light has a propagation direction different to the propagation direction of the light to be encoded. According to the invention there is also provided a micro-structured optical waveguide, which may have an axial direction, which waveguideincludes sections that are elongated in the axial direction and comprise a non-linear material having an index of refraction whichchanges as a non-linear function of light intensity. This optical waveguide, which may be an optical fibre, includes a light guiding core region, and the waveguide is dimensioned for providing spatial overlap between the sections filled with the non-linear material and light propagating within the waveguide. There is furthermore provided an optical switching device and an optical intensity limiting device which may be based on the micro-structured optical waveguide of the invention.
Abstract:
A short pulse generation system and method of generating a short pulse signal are provided. The system includes a fiber chain having an input for receiving an optical signal having a plurality of optical pulses. The fiber chain is nonlinear with respect to the optical signal and includes a first normal fiber segment having a relatively small chromatic parameter, a first abnormal fiber segment having a relatively large chromatic parameter coupled to an output of the first normal fiber segment, and a second abnormal fiber segment having a relatively small chromatic parameter coupled to an out of the first abnormal fiber segment. The system includes a filter stage coupled to an output of the fiber chain and that has a transparent wavelength selected to regenerate the signal. A short pulse signal is produced when the optical signal is coupled to the input.
Abstract:
A variable optical attenuator device is provided for modulating an optical signal. The attenuator device includes a variable attenuation assembly with an electrochromic structure interposed between a first electrode and a second electrode. The electrochromic structure is configured to reversibly change its optical characteristics from a bleached off state to a colored active state under the influence of an electrical potential applied to the first and second electrodes to thereby modulate the optical signal. The optical attenuator device includes at least one lens attached to the variable attenuation assembly. The lens cooperates with the variable attenuation assembly to direct the optical signal towards the electrochromic structure. Waveguides such as optical fibers define ports at the outer endface of the lens for the optical signal.
Abstract:
An optical communication assembly includes a demultiplexer coupled to an input fiber, a multiplexer coupled to an output fiber and a plurality of optical fibers. Each optical fiber is coupled to one or both of the demultiplexer and multiplexer. A plurality of attenuators are each coupled to an optical fiber in the pluality of optical fibers.
Abstract:
A wavelength tunable light source includes an optical pulse generating section for generating an optical pulse; an amplitude control section for controlling the amplitude of the optical pulse generated by the optical pulse generating section by superimposing control light on the optical pulse to output a short optical pulse; and an optical frequency converting section for converting the frequency of the short optical pulse by launching the short optical pulse output from the amplitude control section into an optical nonlinear medium whose refractive index varies in response to the electric-field intensity of the incident light. The amplitude control section can be configured such that it carries out the time division multiplexing and outputs the short optical pulse, thereby constituting an optical pulse light source.
Abstract:
A drop AOTF has a first AOTF that includes an optical fiber with a longitudinal axis, an acoustic wave propagation member with a proximal end and a distal end and an acoustic wave propagation member. The acoustic wave propagation member propagating an acoustic wave from the proximal to the distal end of the acoustic wave propagation member. An optical circulator, with first, second and third ports, is coupled to the first AOTF at the third port. A mode coupler is coupled to the first AOTF. A orthogonal-polarization reflective mirror is coupled to the mode coupler.
Abstract:
Provided are a simple and convenient apparatus capable of analyzing carbon isotope 14 C and a method of analyzing the carbon isotope. A carbon isotope analyzer 1 including an isotopic carbon dioxide generator 40 to generate isotopic carbon dioxide from a carbon isotope; a spectrometer 10 including an optical resonator 11 having a pair of mirrors 12, and a photodetector 15 to determine the intensity of light transmitted from the optical resonator 11; and a light generator 20 including a light source 23, a first optical fiber 21 to transmit a light beam from the light source 23, a second optical fiber 22 for wavelength conversion, the second optical fiber 22 branching from the first optical fiber 21 at a point and combining with the first optical fiber 21 at another point downstream of the branching point, and a non-linear optical crystal 25 to generate light having the absorption wavelength of the isotopic carbon dioxide on the basis of the difference in frequency between light beams transmitted through the optical crystal 25.
Abstract:
An optical filter device may include an optical fiber having a core and a cladding surrounding the core, the optical fiber having a tapered portion. The optical filter device may include an index selectable material surrounding the tapered portion and having an index of refraction being selectable based upon a physical characteristic. The optical filter device may include a device configured to change the index selectable material to select the index of refraction to selectively filter out a mode within the optical fiber.