Systems and methods are provided for optimizing the energy output of a laser system, such as a Light Detection and Ranging (LIDAR) system, by allowing the laser system to be tuned while the laser is in operation. For example, in an embodiment, a sensor, such as a photoresistor, is used to perform a scan to determine whether turning the crystal will result in increased energy. Crystal turners, such as servo motors, can be used to turn the crystal until the energy stops increasing.

An optical system for narrowing the bandwidth of a beam of incident radiation includes an optical mixing unit configured to receive a first beam of radiation and a second beam of radiation. The first and second beams are spatially chirped and the first beam is inverted relative to the second beam. The optical mixing unit includes an optical mixing member, which includes a nonlinear optical medium to mix the first and second beams into an output beam having a narrower bandwidth than the beam of incident radiation.

A visible-to-ultraviolet band optical frequency converter. The processing period of a nonlinear optical crystal is controlled to provide an additional period phase to meet a phase matching condition so as to realize effective optical frequency conversion. The additional period phase is characterized in that phase gratings periodically arranged according to different refractive indexes are formed in the crystal through technologies, including laser micro-processing, ion etching and the like, a nonlinear frequency conversion inverse process is avoided through the periodic structure damage of the crystals in the phase gratings and an additional period phase is provided, phase mismatch caused by the insufficient double refraction of the nonlinear optical crystal is avoided, and efficient frequency doubling or sum frequency output is realized.

An optical frequency mixing module is described that comprises a nonlinear medium for frequency mixing the photons of one or more input optical fields to generate an output optical field; a nonlinear medium tuner for automatically phase matching the nonlinear medium to the one or more input optical fields to select the wavelength of the output optical field generated by the nonlinear medium; and a first direction correcting optic. The position of the first direction correcting optic relative to the nonlinear medium is dependent upon the selected wavelength of the output optical field and therefore ensures that the position and angle of propagation of this field remains constant and independent of its wavelength of. The optical frequency mixing modules therefore provides a means for automatically selecting the wavelength of the output field with no deviation being imparted onto the position or angle of propagation of the output field.

An object is to provide, for example, a method for manufacturing an optical wavelength conversion device having a structure that enables efficient formation of crystal regions on the surface of, or inside, an amorphous material. An amorphous main body is intermittently irradiated with a first laser beam for generating a high-density excited electron region inside the main body and a second laser beam for heating the high-density excited electron region, with respective focus regions of the first and second laser beams overlapping each other. During the intermittent irradiation with the first and second laser beams, the relative position of the main body and the overlapping focus region of the first and second laser beams are varied. This enables part of the main body where the overlapping focus region moves to serve as a heat source for forming a crystal region.

A pump beam (12) is pre-tilted by subjecting the pump beam to pulse-front-tilting, the thus obtained tilted-pulse-front pump beam is then coupled into the nonlinear optical medium. THz radiation is generated in the optical medium by nonlinear optical processes, in particular by optical rectification, by the pump beam. A pulse-front-tilt of the pump beam satisfying the velocity matching condition of v.sub.p,cs cos()=v.sub.THz,f is induced as a sum of a plurality of pulse-front-tilts separately induced as a partial pulse-front-tilt of the pump beam in subsequent steps. The last step of pulse-front-tilting of the pump beam is performed by coupling the pump beam into the nonlinear optical medium through a stair-step structure (40) formed in an entry surface (51) of the nonlinear optical medium which forms an angle () of a given non-zero size with an exit surface (52) of said nonlinear optical medium.

A nonlinear fiber interferometer is disclosed suitable for fiber sensor and other applications. A first nonlinear fiber section amplifies probe and conjugate sidebands of a pump through four-wave mixing. A second section introduces a phase shift to be measured, for example from a sensor. A third nonlinear fiber section amplifies with phase-sensitive gain to increase signal-to-noise ratio. Based on phase-sensitive output power of probe and/or conjugate components, the phase shift can be measured. Superior performance can be obtained by balancing gain between the (first and third) nonlinear sections. Non-fiber, for example photonic integrated circuit, embodiments are disclosed. Differential sensing, alternative detection schemes, sensing applications, associated methods, and other variations are disclosed.

A visible ultraviolet band optical frequency converter. The processing period of a nonlinear optical crystal is controlled to provide an additional period phase to meet a phase matching condition so as to realize effective optical frequency conversion. The additional period phase is characterized in that phase gratings periodically arranged according to different refractive indexes are formed in the crystal through technologies, including laser micro-processing, ion etching and the like, a nonlinear frequency conversion inverse process is avoided through the periodic structure damage of the crystals in the phase gratings and an additional period phase is provided, phase mismatch caused by the insufficient double refraction of the nonlinear optical crystal is avoided, and efficient frequency doubling or sum frequency output is realized.

A method of forming an emitting array of waveguides, comprising providing a plurality of waveguides that exhibit different propagation constants so as to ensure that nearby waveguides do not couple evenly over parallel propagation lengths by varying a length in one or more dimensions of respective waveguides, whereby the respective waveguides are phasemismatched with at least their nearest neighbor.

An object is to provide, for example, a method for manufacturing an optical wavelength conversion device having a structure that enables efficient formation of crystal regions on the surface of, or inside, an amorphous material. An amorphous main body is intermittently irradiated with a first laser beam for generating a high-density excited electron region inside the main body and a second laser beam for heating the high-density excited electron region, with respective focus regions of the first and second laser beams overlapping each other. During the intermittent irradiation with the first and second laser beams, the relative position of the main body and the overlapping focus region of the first and second laser beams are varied. This enables part of the main body where the overlapping focus region moves to serve as a heat source for forming a crystal region.