There is disclosed in one example a communication system, including: a data transmission interface; and a wavelength division multiplexing (WDM) silicon laser source to provide modulated data on a carrier laser via the data transmission interface, the WDM laser including a single laser cavity to generate an internally multiplexed multi-wavelength laser, the single laser cavity including a filter having a first grating period to generate a first wavelength and a second grating period to generate a second wavelength, the second grating period superimposed on the first grating period.

A laser oscillator includes: a plurality of laser media to emit laser beams having different wavelengths; a diffraction grating to emit, in a superimposed state, the laser beams incident from the laser media; a partially reflective element to reflect part of the laser beams emitted from the diffraction grating and return the part of the laser beams to the diffraction grating, and to transmit a remainder; and a plurality of lenses each disposed between a corresponding one of the laser media and the diffraction grating. The lenses are each disposed in an optical path formed between a corresponding one of the laser media and the diffraction grating, and the lenses superimpose the laser beams from the laser media on an incident surface of the diffraction grating such that the laser beams have an equal outer diameter.

A measurement system for performing measurement by Brillouin scattering analysis, the system comprising a laser emitter device (10) configured to emit an incident wave (0) and a reference wave (0B), the incident wave presenting an incident frequency (0) and the reference wave presenting a reference frequency (0B), the reference frequency (0B) being shifted from the incident frequency (0) by a predetermined value (B). The system is configured to: project the incident wave (0) into the optical fiber (25); receive in return a backscattered wave (0S); generate a composite wave (0-S, 0-B) combining the backscattered wave (0S) and the reference wave (S0B); and determine at least one property relating to the fiber by analyzing a Brillouin spectrum of the composite wave (0-S, 0-B). Advantageously, the incident wave and the reference wave come from a dual-frequency vertical-cavity surface-emitting laser source (12) forming part of the laser emitter device.

A monolithic integrated semiconductor random laser composed of a gain region and random feedback region, comprising: a substrate, a lower confinement layer on the substrate, an active layer on the lower confinement layer, an upper confinement layer on the active layer, a strip-shaped waveguide layer longitudinally made in middle of the upper confinement layer, a P.sup.+ electrode layer divided into two segments by an isolation groove and made on the waveguide layer, and an N.sup.+ electrode layer on a back face of the lower confinement layer. The two segments of the P.sup.+ electrode layer correspond respectively to the gain region and the random feedback region. The random feedback region uses a doped waveguide to randomly feed back light emitted and amplified by the gain region. As a result, random laser is emitted. Frequency and intensity of laser emitted by semiconductor laser are random, and a monolithic integration structure is used, making semiconductor laser be light, small, stable in performance, and strong in integration.

Examples disclosed herein relate to multi-wavelength semiconductor comb lasers. In some examples disclosed herein, a multi-wavelength semiconductor comb laser may include a waveguide included in an upper silicon layer of a silicon-on-insulator (SOI) substrate. The comb laser may include a quantum dot (QD) active gain region above the SOI substrate defining an active section in a laser cavity of the comb laser and a dispersion tuning section included in the laser cavity to tune total cavity dispersion of the comb laser.

A quantum dot comb laser includes a body defining a lasing cavity and an extension defining an external cavity, the FSR of the lasing cavity being an inverse of an integer multiple of the FSR of the external cavity.

The present disclosure describes broadband optical emission sources that include a stack of semiconductor layers, wherein each of the semiconductor layers is operable to emit light of a different respective wavelength; a light source operable to provide optical pumping for stimulated photon emission from the stack; wherein the semiconductor layers are disposed sequentially in the stack such that a first one of the semiconductor layers is closest to the light source and a last one of the semiconductor layers is furthest from the light source, and wherein each particular one of the semiconductor layers is at least partially transparent to the light generated by the other semiconductor layers that are closer to the light source than the particular semiconductor layer. The disclosure also describes various spectrometers that include a broadband optical emission device, and optionally include a tuneable wavelength filter operable to allow a selected wavelength or narrow range of wavelengths to pass through.

A light-emitting semiconductor chip (100) is provided, having a first semiconductor layer (1), which is at least part of an active layer provided for generating light and which has a lateral variation of a material composition along at least one direction of extent. Additionally provided is a method for producing a semiconductor chip (100).

A multi-wavelength laser apparatus is provided. The multi-wavelength laser apparatus may include a meta-mirror layer having a surface in which a plurality of patterns are formed, a laser emitter disposed on the meta-mirror layer, and an upper-mirror layer disposed on the laser emitter. The multi-wavelength laser apparatus may further include a conductive graphene layer between the meta-mirror layer and the laser emitter.

A semiconductor laser tuned with an acousto-optic modulator. The acousto-optic modulator may generate standing waves or traveling waves. When traveling waves are used, a second acousto-optic modulator may be used in a reverse orientation to cancel out a chirp created in the first acousto-optic modulator. The acousto-optic modulator may be used with standing-wave laser resonators or ring lasers.