With a wavelength conversion device based on a nonlinear optical effect, when arrayed waveguides including an intended nonlinear waveguide are fabricated, unwanted slab waveguides are inevitably formed. The slab waveguides can cause an erroneous measurement in the selection of a waveguide having desired characteristics from the arrayed waveguides. The erroneous measurement can lead to redoing steps for fabricating the wavelength conversion device and a decrease in the yield and inhibit the evaluation of the characteristics in selection of the waveguide and the subsequent fabrication of the wavelength conversion device from being efficiently performed. A wavelength conversion device according to the present invention includes a plurality of waveguides formed on a substrate, and a plurality of slab waveguides that are arranged substantially in parallel with and spaced apart from the plurality of waveguides, and each of the slab waveguides has a grating structure that reflects light of a particular wavelength.

A system for frequency conversion, comprises a laser source and a harmonic generation crystal. The laser source is configured to produce optical pulse energy of less than 100 μJ. The harmonic generation crystal comprises a structure characterized by a nonlinear susceptibility, and a crystal grating period which adiabatically varies along the longitudinal direction in a manner that the crystal grating period is inversely proportional to a crystal grating function of a coordinate z measured along the longitudinal direction.

The invention relates to a method for producing waveguides (201) from a material (202) of the KTP family comprising the following method steps: b) treating the material (202) in such a way that a periodic poling of the material (202) is achieved, c) treating the material (202) in a molten salt bath (309c), which contains rubidium ions, characterized in that the molten salt bath (309c) which contains rubidium ions in step c) satisfies the following boundary conditions: the mole fraction of rubidium nitrate (RbNO.sub.3) in the melt lies in the range of 86-90 mol % at the beginning of the treatment, the mole fraction of potassium nitrate (KNO.sub.3) in the melt lies in the range of 10-12 mol % at the beginning of the treatment, the mole fraction of barium nitrate (Ba(NO.sub.3).sub.2) in the melt lies in the range of 0.5-1 mol % at the beginning of the treatment, the temperature of the melt lies in the range of 357-363° C. during the treatment. Thus the problem is solved, when reversing the known method steps, of achieving substantially identical diffusion depths of the ions during the ion exchange in order to produce periodically poled waveguides as free of corrugation as possible.

A wavelength conversion element manufacturing method capable of realizing, in a wavelength conversion element having a structure in which a thin film substrate having a periodic polarization inversion structure and a support substrate are laminated, highly efficient wavelength conversion by confining light in a cross-sectional area smaller than in the known art. The manufacturing method includes steps of forming a periodic polarization inversion structure on a first substrate made of a second-order nonlinear optical crystal and forming a damage layer in the first substrate by implanting ions from one substrate surface to obtain a first substrate for bonding, directly bonding a second substrate having a bonding surface having a smaller refractive index than the first substrate to the one substrate surface of the first substrate at the bonding surface, and peeling the first substrate directly bonded to the second substrate being the support substrate with the damage layer as a boundary to remove a part of the first substrate.

A wavelength conversion element manufacturing method capable of realizing, in a wavelength conversion element having a structure in which a thin film substrate having a periodic polarization inversion structure and a support substrate are laminated, highly efficient wavelength conversion by confining light in a cross-sectional area smaller than in the known art. The manufacturing method includes steps of forming a periodic polarization inversion structure on a first substrate made of a second-order nonlinear optical crystal and forming a damage layer in the first substrate by implanting ions from one substrate surface to obtain a first substrate for bonding, directly bonding a second substrate having a bonding surface having a smaller refractive index than the first substrate to the one substrate surface of the first substrate at the bonding surface, and peeling the first substrate directly bonded to the second substrate being the support substrate with the damage layer as a boundary to remove a part of the first substrate.

The invention is related to a parametric light generation method and its application and belongs to the technical field of laser and nonlinear optics. The generation method comprises steps as follows: a nonlinear optical material that meets the sum-frequency phase-matched conditions, namely it shall satisfy the energy conservation condition ω.sub.p+ω.sub.i=ω.sub.s and the momentum conservation condition n.sub.pω.sub.p+n.sub.iω.sub.i=n.sub.sω.sub.s simultaneously, is provided; laser light with a wavelength of λ.sub.p is injected into the said nonlinear optical material as pump light; then, the material will output signal light with a wavelength of λ.sub.S, namely the tunable sum-frequency parametric light. With sum-frequency as the basic principle, the invention can realize frequency up-conversion and obtain visible and UV light sources through simple infrared light sources easily.

Reduction of output power of light with a wavelength converted is suppressed, which is caused by a pyroelectric effect that occurs when a temperature of a wavelength conversion element including a ferroelectric substrate is changed. Provided is a wavelength conversion device that generates light different from a wavelength of a signal light when the signal light is inputted, and includes a wavelength conversion element that converts a wavelength of the signal light, and a temperature control element for controlling a temperature of the wavelength conversion element, wherein the wavelength conversion element and the temperature control element are sealed in an inside of a metal casing, the wavelength conversion element includes an optical waveguide core and a substrate having a lower refractive index to the signal light than the optical waveguide core, and the substrate is a ferroelectric substance in which directions of spontaneous polarization are random.

This invention proposes to use a specially designed layered nonlinear optic (LNO) for intracavity harmonic generation. The LNO generates the harmonic and guides the generated harmonic beam to a different path from the fundamental beam path with total internal reflection, a phenomenon that all lights are reflected when lights in one (“internal”) optic strike sufficiently obliquely against the interface with a second (“external”) optic, in which the refractive index is lower than that in the internal optic. No coating is necessary for the harmonic inside the fundamental beam laser cavity. The generated harmonic beam does not travel through any surface inside the fundamental beam cavity, either. Hence this invention improves the reliability of intracavity harmonic generation laser especially if the harmonic is in the UV range.

Disclosed embodiments include laser systems. An illustrative laser system includes a tunable laser. A beam splitter is operatively couplable to an output of the laser and is configured to split light output from the laser into a first path and a second path. A first modulator is disposed in the first path and is configured to generate first set of sidebands. A bandpass filter circuit includes a fiber Bragg grating filter and is operatively couplable to receive output from the first modulator and to pass a selected sideband of the first set of sidebands. A lock circuit is disposed in the second path, is configured to determine and stabilize wavelength of the laser, and is further configured to cooperate with the fiber Bragg grating filter to maintain a static lock point for the laser while allowing output of the first path to be tunable with respect to the lock point.

Disclosed embodiments include laser systems. An illustrative laser system includes a tunable laser. A beam splitter is operatively couplable to an output of the laser and is configured to split light output from the laser into a first path and a second path. A first modulator is disposed in the first path and is configured to generate first set of sidebands. A bandpass filter circuit includes a fiber Bragg grating filter and is operatively couplable to receive output from the first modulator and to pass a selected sideband of the first set of sidebands. A lock circuit is disposed in the second path, is configured to determine and stabilize wavelength of the laser, and is further configured to cooperate with the fiber Bragg grating filter to maintain a static lock point for the laser while allowing output of the first path to be tunable with respect to the lock point.