A method for sweeping an electromagnetic radiation source (12) to produce single mode operation having an optimized side-mode suppression ratio over a continuous range of wavelengths within a prescribed temporal profile, the electromagnetic radiation source is configured to output electromagnetic radiation at a given wavelength based upon parameters. The method includes determining a set of parameter combinations that satisfy a condition for a desired set of wavelengths and a maximum side mode suppression ratio over the range of wavelengths. The set of parameter combinations define sub-paths for transitioning from one wavelength to another wavelength. Combinations of select sub-paths provide a multivariate path for transitioning over the range of wavelengths. The method also includes controlling the semiconductor laser to emit electromagnetic radiation over the range of wavelengths by traversing the multivariate path in a desired manner.

In a laser system according to a viewpoint of the present disclosure, a first amplifier amplifies first pulsed laser light outputted from a first semiconductor laser system into second pulsed laser light, a wavelength conversion system converts the second pulsed laser light in terms of wavelength into third pulsed laser light, and an excimer amplifier amplifies the third pulsed laser light. The first semiconductor laser system includes a first current controller that controls current flowing through a first semiconductor laser in such a way that first laser light outputted from the first semiconductor laser is caused to undergo chirping and a first semiconductor optical amplifier that amplifies the first laser light into pulsed light. The laser system includes a control section that controls the amount of chirping performed on the first pulsed laser light in such a way that excimer laser light having a target spectral linewidth is achieved.

A method and system for using a wavelength tunable semiconductor laser as an excitation source of a fiber optics sensing system (FOSS) based on a thermoelectric control of a laser sweep. A device can include an optical fiber; a set of fiber Bragg gratings disposed within the optical fiber; a single-frequency laser (SFL) operatively connected to the optical fiber; a thermoelectric cooler operatively connected to the SFL; a controller comprising a processor in communication with the thermoelectric cooler; and a nontransitory, computer-readable storage medium in communication with the processor. The nontransitory, computer-readable storage medium can store instructions that, when executed by the processor, cause the processor to perform operations including determining a strain value at a first fiber Bragg grating of the set of fiber Bragg gratings based on a second laser signal received at the device that is reflected from an interaction of a first laser signal with the first fiber Bragg grating.

A semiconductor laser, an optical transmitter component, an optical line terminal, and an optical network unit. The semiconductor laser includes a substrate, a lower waveguide layer, a lower confining layer, a central layer, an upper confining layer, a grating layer, an upper waveguide layer, and an electrode layer that are sequentially formed on the substrate. The upper confining layer, the central layer, and the lower confining layer in a filtering region form a core layer of the filtering region. The grating layer in the filtering region includes a slanted grating. Thus, a modulation chirp and dispersion of a transmitted optical pulse can be reduced.

Vertical-cavity surface-emitting lasers (VCSELs) and methods for making such are provided. The VCSELs include stepped upper reflectors having respective differently-sized apertures. This allows the lower portion of the reflector to have formed therein a wider-diameter aperture to allow for increased current injection. The upper portion of the reflector has formed therein a narrower-diameter, mode-selecting aperture to allow higher-order modes to be reduced, leading to single-mode operation. The VCSELs are thus capable of higher-power emission in a single mode, allowing for longer-distance signaling over optical fiber, despite modal dispersion within the fiber and/or at the coupling between the VCSEL and the fiber. The two differently-sized apertures can be formed via respective lateral oxidation processes following etch-down to form the respective steps of the upper reflector. Differences in composition across the upper reflector results in temperature-dependence of the oxidation process, allowing the apertures to be formed with different sizes.

A method of manufacturing a light emitting element includes, at least: (A) forming a stacked structure 20 which includes a GaN-based compound semiconductor and in which a first compound semiconductor layer 21, an active layer 23, and a second compound semiconductor layer 22 are stacked, and forming a concave mirror section 43 on a first surface side of the first compound semiconductor layer 21; then (B) forming a photosensitive material layer 35 over the second compound semiconductor layer 22; and thereafter (C) exposing the photosensitive material layer 35 to light from the concave mirror section side through the stacked structure 20, to obtain a treatment mask layer including the photosensitive material layer 35, and then processing the second compound semiconductor layer 22 by use of the treatment mask layer.

An on-chip ultra-narrow linewidth laser and a method for obtaining a single-longitudinal mode ultra-narrow linewidth optical signal are provided in the present invention. The on-chip ultra-narrow linewidth laser includes a laser generating gain unit for generating a broad-spectrum initial optical signal and performing wavelength filtering on the generated optical signal, and also includes a distributed scattering feedback unit for performing linewidth compression on the optical signal; the laser generating gain unit is connected with the distributed scattering feedback unit, so that the optical signal generated by the laser generating gain unit is subjected to wavelength filtering and then output to the light guide component of the distributed scattering feedback unit to scatter to form an optical signal with a narrower linewidth to achieve linewidth compression, and the optical signal returning along the original path and fed back to the optical signal of the laser generating gain unit is subjected to gain amplification and wavelength filtering once again, repeating until achieving a steady state so as to obtain a single-longitudinal mode ultra-narrow linewidth optical signal. The laser can obtain a steady single-longitudinal mode ultra-narrow linewidth optical signal, and is simple in structure and small in volume.

A low noise, single mode laser includes a semiconductor gain element generating light and having a highly reflective first end forming a first end of a laser cavity. The gain element may be monolithically or discretely integrated with, or distinct from, and coupled to a waveguide comprised of a low loss material with a refractive index ‘n’ greater than 3. The waveguide includes a Bragg grating forming the second end of the laser cavity. A cavity phase control section may be provided between the gain element and the Bragg grating. Two photodetector monitors provide a feedback signal for locking the light from the gain element to a specific wavelength on the Bragg grating reflection spectrum by varying at least one of the cavity phase control section and the gain element bias current. The Bragg grating may have a physical length larger than 10 mm and that occupies at least 50% of the optical length of the external cavity.

Single-mode distributed-feedback (DFB) lasers including single mode DFB waveguides with tapered grating structures are provided herein. Tapered grating structures provide for single mode DFB waveguides with predictable single mode operation. Uniform grating structures may provide for single mode operation, however DFB waveguides implementing uniform grating structures may operate at one of two single modes. Advantageously, DFB waveguides with tapered gratings operate with a spectrally narrow single mode at the same predictable single mode for all DFB waveguides with substantially identical specifications. Such predictability may lead to increased yield during manufacture of DFB waveguides with tapered gratings.

Narrow beam divergence semiconductor sources are operable to generate a beam having a substantially narrow beam divergence, an emission wavelength, and a substantially uniform beam intensity. The presence of an extended length mirror can help suppress one or more longitudinal and/or transverse modes such that the beam divergence and/or the spectral width of emission is substantially reduced.