GaN-based nanowire heterostructures have been intensively studied for applications in light emitting diodes (LEDs), lasers, solar cells and solar fuel devices. Surface charge properties play a dominant role on the device performance and have been addressed within the prior art by use of a relatively thick large bandgap AlGaN shell covering the surfaces of axial InGaN nanowire LED heterostructures has been explored and shown substantial promise in reducing surface recombination leading to improved carrier injection efficiency and output power. However, these lead to increased complexity in device design, growth and fabrication processes thereby reducing yield/performance and increasing costs for devices. Accordingly, there are taught self-organising InGaN/AlGaN core-shell quaternary nanowire heterostructures wherein the In-rich core and Al-rich shell spontaneously form during the growth process.

Example embodiments disclose a tunable optical pair source (TOPS) configured to generate first and second output optical beams having respective first and second frequencies that are phase locked with each other. The TOPS may include a first laser, such as a tunable laser, configured to generate a first laser beam, a radio frequency (RF) oscillator configured to transmit an RF reference signal, a beam splitter in optical communication with the first laser, and an electro-optic modulator configured to modulate the second split beam with the RF reference signal to form a modulated beam having a first sideband comb comprising a plurality of harmonics. Additionally, the TOPS may include an optical filter configured to receive the modulated beam and output a filtered optical beam, and a second laser configured to generate a second laser beam at the second frequency, the second laser being configured to receive the filtered optical beam as a seed.

System and method for utilizing a serial array (10) of large laser cores (11), positioned inside an external cavity formed with full reflection mirrors (12) and a partial reflection mirror (13), containing a mode-selection mechanism, based on a seeding laser (14), a Fabry-Perot (16), and an isolator (15), for ensuring only the axial wave (17) can exist, generating correspondingly an output beam (18) of high power as well high beam quality.

A surface-emitting laser includes an output unit. The output unit has an oblong-shaped VCSEL (vertical-cavity surface-emitting laser) structure. The output unit operates in an oscillation state in which a current that is larger than the oscillation threshold value is injected. The output unit receives a coherent seed light via a coupling surface at one end of the VCSEL structure in the longitudinal direction thereof. The seed light thus received propagates as a slow light through the VCSEL structure in the longitudinal direction thereof while being reflected multiple times in the vertical direction within the VCSEL structure. An output light is extracted from the upper surface of the VCSEL structure.

Examples herein relate to optical systems. In particular, implementations herein relate to an optical system including an optical transmitter configured to transmit optical signals. The optical transmitter includes a first optical source configured to emit light having different wavelengths, a waveguide, and an optical coupler configured to couple the emitted light from the first optical source to the waveguide. The optical transmitter further includes an array of two or more second optical sources coupled to the waveguide, each of the two or more second optical sources configured to be injection locked to a different respective wavelength of the emitted light transmitted via the waveguide from the first optical source. In some implementations, the first optical source is a master comb laser and the two or more second optical sources are slave ring lasers.

Top emitting vertical cavity surface emitting lasers (VCSELs) are described with various top side optical gratings, etched into and/or fabricated over the VCSELs, to configure optical emission properties to suite a wide range of applications. Top side gratings are configured for spanning one or multiple emitters in any desired alignment/misalignment, using a wide range of refractive index materials and arrangements, levels of dimensionality (1D, 2D or 3D), forms of chirping of the grating, various grating periods, transmissive/reflective properties and in-plane coupling, ranges of diffractive orders, different relative amplitudes of transmitted and reflected orders, different polarizations, different levels of collimation, different levels of divergence, different diffraction and reflection, different beam diffusion, fixed or varied rotation of optical output, and far field engineering of the optical output.

The present invention provides one or more injection-lockable whistle-geometry semiconductor ring lasers, which may be cascaded, that are integrated on a common silicon-on-insulator (SOI) substrate with a single-frequency semiconductor master laser, wherein the light output from the semiconductor master laser is used to injection-lock the first of the semiconductor ring lasers. The ring lasers can be operated in strongly injection-locked mode, while at least one of them is subjected to direct injection current modulation.

Example embodiments disclose a tunable optical pair source (TOPS) configured to generate first and second output optical beams having respective first and second frequencies that are phase locked with each other. The TOPS may include a first laser, such as a tunable laser, configured to generate a first laser beam, a radio frequency (RF) oscillator configured to transmit an RF reference signal, a beam splitter in optical communication with the first laser, and an electro-optic modulator configured to modulate the second split beam with the RF reference signal to form a modulated beam having a first sideband comb comprising a plurality of harmonics. Additionally, the TOPS may include an optical filter configured to receive the modulated beam and output a filtered optical beam, and a second laser configured to generate a second laser beam at the second frequency, the second laser being configured to receive the filtered optical beam as a seed.

Examples herein relate to optical systems. In particular, implementations herein relate to an optical system including an optical transmitter configured to transmit optical signals. The optical transmitter includes a first optical source configured to emit light having different wavelengths, a waveguide, and an optical coupler configured to couple the emitted light from the first optical source to the waveguide. The optical transmitter further includes an array of two or more second optical sources coupled to the waveguide, each of the two or more second optical sources configured to be injection locked to a different respective wavelength of the emitted light transmitted via the waveguide from the first optical source. In some implementations, the first optical source is a master comb laser and the two or more second optical sources are slave ring lasers.

An optical line terminal includes an optical comb generator, N downlink channels D.sub.k, and N uplink-photodetectors PD.sub.k. The optical comb generator is configured to generate a carrier signal having an optical-frequency-comb spectrum and including N optical tones T.sub.k and N optical tones R.sub.k, k={1, 2, . . . , N}. Each of the N downlink channels D.sub.k is optically coupled to the optical comb generator and is configured to generate a respective downlink signal DS.sub.k that includes optical tone T.sub.k modulated by downlink data. Each of the N uplink-photodetectors PD.sub.k is configured to receive a respective one of a plurality of modulated uplink signals US.sub.k, having optical tone R.sub.k as a carrier signal.