Abstract: Systems and methods for stabilizing laser frequency based on an isoclinic point of an atomic or molecular medium are provided herein. A system may include: a transmission cell containing a gas and configured to transmit light from the laser, the gas having an absorption spectrum with an isoclinic point; a photodiode generating an output based on an amplitude of transmitted laser light; and circuitry configured to tune the frequency of the laser to the isoclinic point of the absorption spectrum based on the output. The absorption spectrum may have first and second overlapping peaks respectively corresponding to first and second transitions of the gas, the isoclinic point being a saddle point between the first and second peaks. The first and second peaks may have substantially equal amplitude as one another and/or may broaden substantially equally as each other as a function of a physical parameter of the gas.

Abstract: The present application relates to a semiconductor laser, in particular such a laser which operates with substantially single longitudinal mode emission. The laser comprising a laser cavity, the laser further comprising a slot having an interface, characterized in that the slot is substantially filled with a reflective material having a large imaginary index relative to the laser cavity material. The interfaces of the slot may be inclined or may have a step for introducing a quarter wave phase shift.

Abstract: A surface emitting laser element that includes a cylindrical mesa post in which a plurality of semiconductor layers including an active layer is grown and that emits a laser light in a direction perpendicular to a substrate surface, the surface emitting laser element including a dielectric multilayer film on a top surface of the mesa post in at least a portion over a current injection area of the active layer; and a dielectric portion that includes layers fewer than layers of the dielectric multilayer film and that is arranged on a portion excluding the portion over the current injection area on the top surface of the mesa post and on at least part of a side surface of the mesa post.

Abstract: Provided are a hybrid laser diode for single mode operation, and a method for manufacturing the hybrid laser diode. The hybrid laser diode includes a silicon layer, an active pattern disposed on the silicon layer, and a bonding layer disposed between the silicon layer and the active pattern. Here, the bonding layer includes diffraction patterns constituting a Bragg grating.

Abstract: A fiber laser arrangement having a high beaming power includes a plurality of continuously operating coherent individual fiber lasers. Pumping energy generated by a common master oscillator operated in the longitudinal mode is distributed to the fiber lasers by way of a fiber splitter, in a branched manner. An integrated electro-optical phase shifter is assigned to each individual fiber laser, and can be controlled by an electronic control system. By appropriate displacements of the optical phases in individual phases of the fiber laser arrangement atmospheric turbulence effects on the propagation path of the laser radiation to a target are compensated in order to obtain an optimal focusing of the entire laser radiation onto the remote target.

Abstract: Among others, RF receivers based on whispering gallery mode resonators are described. In one aspect, a photonic RF device includes a laser that is tunable in response to a control signal and produces a laser beam at a laser frequency. The RF device includes a first optical resonator structured to support a whispering gallery mode circulating in the first optical resonator, the optical resonator being optically coupled to the laser to receive a portion of the laser beam into the optical resonator in the whispering gallery mode and to feed laser light in the whispering gallery mode in the optical resonator back to the laser to stabilize the laser frequency at a frequency of the whispering gallery mode and to reduce a linewidth of the laser. The RF device includes a second optical resonator made of an electro-optic material to support a whispering gallery mode circulating in the optical resonator.

Abstract: A laser beam steering apparatus includes a beam steering cell with an adjustable shape, with the cell having opposing Fabry-Perot filters, and a steering mechanism coupled to the cell to adjust its shape so that the direction of a laser beam emitted from the cell is changed in response to a change in the cell shape.

Abstract: An apparatus includes a pulsed laser source that produces a pulsed laser beam at an input repetition rate and an input pulse power, a passive pulse splitter that receives the pulsed laser beam and outputs a signal including a plurality of sub-pulses for each input pulse of the pulsed laser beam, a sample, and a detector. The output signal has a repetition rate that is greater than the input repetition rate and the powers of each of the sub-pulses are less than the input pulse power. The sample is placed in the path of a sample beam that is formed from the beam that exits the pulse splitter. The detector receives a signal of interest emitted from the sample.

Abstract: An integrated photonic circuit includes waveguides (12-19) and other photonic components. The photonic circuit has a first part (1) and a second part (2), the first part and the second part being connected to a mirror in the form of a half 2×2 multimode interferometer (MMI) (32), which comprises solely one half MMI (31) in a longitudinal direction, the half MMI (32) having two ports (33, 34) and being arranged to reflect half of the light that is incident on one of the ports to one port and transmit half of the incident light to the second port, and the free surface (35) of the half MMI (32) having been treated with a highly reflective material.

Abstract: The present invention relates to an optical frequency synthesizer and an optical frequency synthesizing method using femtosecond laser optical injection locking, which inject a femtosecond laser optical frequency comb into a diode laser, thus obtaining single-mode laser light, phase-locked to only a single mode in the optical frequency comb, and which change the optical frequency and interval, that is, the repetition rate, of a femtosecond laser, together with the frequency of a semiconductor laser, thus scanning optical frequencies while realizing a single desired optical frequency. The optical frequency synthesizer using femtosecond laser optical injection locking, includes a mode-locked femtosecond laser (110), which is a master laser, and a diode laser (120), which is a slave laser and into which laser light emitted from the femtosecond laser is injected.

Abstract: A heat sink has a first flat plate, a partition plate, and a second flat plate. The first flat plate has an upper surface in which a first recess is formed. The second flat plate has a lower surface in which a second recess is formed, and an upper surface on which a semiconductor laser element is mounted. These recesses form a part of a refrigerant channel. The partition plate has a lower surface covering the first recess, an upper surface covering the second recess, and at least one through hole having the first recess communicated with the second recess. The first flat plate and the second flat plate both have a first coefficient of thermal expansion. The partition plate has a second coefficient of thermal expansion lower than the first coefficient of thermal expansion.

Abstract: In one embodiment, a photo-darkening resistant optical fiber includes a waveguide having a numerical aperture less than 0.15. The waveguide includes a core having a refractive index n1 and a pedestal having a refractive index n2, and wherein the fiber includes a first cladding having a refractive index n3 surrounding the pedestal, wherein n1 is greater than n2, n2 is greater than n3. The core includes silica, a concentration of alumina of between approximately 0.3 to 0.8 mole percent, a concentration of phosphate of substantially 15 mole percent, a concentration of ytterbium substantially in the range 20000 to 45000 ppm. The pedestal can include silica, phosphate and germania. The core can have substantially zero thulium dopant.

Abstract: An objective of the present invention is to provide a surface emitting laser capable of selectively generating a laser oscillation in the fundamental mode and thereby emitting a single-wavelength laser light. In a surface emitting laser including an active layer and a two-dimensional photonic crystal provided on one side of the active layer, a reflector 45 or 46 is provided at least at a portion of the circumference of the two-dimensional photonic crystal. The reflector has a reflectance distribution in which the reflectance has a maximum value at a position where the amplitude envelope of the fundamental mode of an internal resonance light created within the two-dimensional photonic crystal. This design strengthens the fundamental mode while suppressing the second mode, thus enabling the laser oscillation in the fundamental mode to be selectively obtained, so that a single-wavelength laser light can be emitted.

Abstract: A semiconductor laser diode element includes a semiconductor laser diode portion including a ridge portion extending in a first direction in which a cavity extends, a groove formed along the ridge portion and a support portion formed along the groove on a side farther from the ridge portion and holding the groove between the support portion and the ridge portion and a support substrate bonded to the semiconductor laser diode portion through a fusion layer, wherein the fusion layer is formed so as to be embedded in the groove, a space from the ridge portion to the support substrate and a space from the support portion to the support substrate.

Abstract: An optical semiconductor device includes an active layer, a first semiconductor layer formed above the active layer and made from a semiconductor material containing Al, a second semiconductor layer formed above the first semiconductor layer and made from a semiconductor material which does not contain any one of Al and P and whose band gap is greater than that of the active layer, and a third semiconductor layer formed above the second semiconductor layer and made from a semiconductor material which does not contain Al but contains P. The second semiconductor layer is formed such that the first semiconductor layer and the third semiconductor layer do not contact with each other.

Abstract: Provided is a VCSEL that includes a lower DBR of a first conductivity type, an active region, and an upper DBR of a second conductivity type, on a substrate. The lower DBR has a first to-be-oxidized Al-containing layer located farther from the active region than a second to-be-oxidized layer that is formed in the upper DBR. Both layers have an oxidized region and a first or a second non-oxidized region surrounded by the oxidized region. The first non-oxidized region is larger than the maximum size of the second non-oxidized region for a single mode oscillation, and smaller than the maximum size of the first non-oxidized region for a single mode oscillation. The second non-oxidized region is larger than the maximum size of the second non-oxidized region for a single mode oscillation. The first non-oxidized region has a size equal to or larger than that of the second non-oxidized region.

Abstract: An all-fiber color laser and a light-illuminating method thereof are disclosed. The steps of the light-illuminating method include: providing a fiber color laser having a pump light source and an optical fiber with a multi-level wavelength gain medium, a first grating assembly and a second grating assembly; radiating a laser via the pump light source; generating a plurality of laser beams with various wavelengths via the multi-level wavelength gain medium; adjusting the deformation of the second grating assembly to control output of the laser beams with various wavelengths; and executing periodical modulation to generate a periodical lengthwise deformation of the second grating assembly for mixing color.

Abstract: Fundamental-wavelength pulses from a fiber a laser are divided into two portions and the two portions are separately amplified. One of the amplified fundamental-wavelength pulse-portions is frequency-doubled. The frequency doubled portion is sum-frequency mixed with the other amplified fundamental wavelength pulse-portions to provide third-harmonic radiation pulses.

Abstract: A powerful fiber laser system is configured with at least one filtering element capable of preventing a backreflected Raman component of the main signal from propagating along the upstream stretch of the system. The filtering element includes a slanted fiber grating, one or more cladding formations disposed in a cladding of fiber and having a refractive index greater than that one of the cladding, but lower than a refractive index of the core, and/or a combination of two spaced apart single mode fibers and a low mode fiber spliced to the opposing ends of the respective SM fibers.

Abstract: In this semiconductor laser device, a semiconductor laser element is so fixed to a base that a distance between a convex side of a warp thereof and the base varies with the warp of the semiconductor laser element at least along a first direction corresponding to an extensional direction of a cavity or a second direction, while a wire bonding portion is provided around a portion of an electrode layer corresponding to the vicinity of a region where the distance between the convex side of the warp of the semiconductor laser element in at least either the first direction or the second direction of the semiconductor laser element and the base is substantially the smallest.