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.

A wavelength tunable light source includes: a common wavelength filter that has periodic transmission peak wavelengths or reflection peak wavelengths and is commonly used for a plurality of channels; a wavelength tunable filter that is coupled to the common wavelength filter and has a one-input and multiple-output configuration which has a plurality of output ports, and that has a plurality of transmission peak wavelengths corresponding to the plurality of channels at the plurality of output ports; and a plurality of gain media optically coupled to the plurality of output ports of the wavelength tunable filter, wherein a plurality of laser cavities that perform laser oscillation at a plurality of different wavelengths are formed between the common wavelength filter and the plurality of gain media.

A diagnostic system is provided with a plurality of semiconductor light emitters, each configured to generate an optical beam, and a beam combiner to generate a multiplexed optical beam. An optical fiber or waveguide communicates at least a portion of the multiplexed optical beam to form an output beam, wherein the output beam is pulsed. A filter, coupled to at least one of a lens and a mirror to receive at least a portion of the output beam, forms an output light. A beam splitter splits the light into a sample arm and a reference arm and directs at least a portion of the sample arm light to a sample. A detection system is configured to receive from the sample at least a portion of reflected sample light, to generate a sample detector output, and to use a lock-in technique with the pulsed output beam.

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.

A continuous optical beat laser element for generating terahertz (THz) waves and a laser source using same includes periodically poled lithium niobate (ppLN) crystals arranged along a predetermined direction forming a surface generally parallel to the predetermined direction. A Ti diffused region is applied on the surface and an array of gold nanowires are applied on the Ti diffused region to form a gold metal-insulator-metal (MIM) element that optimizes coupling and channeling of THz radiation from the crystals into the gold nanowires. The system provides a simple, stable, compact and cost-effective THz source using a widely tunable C-band SOA-based laser to excite a non-linear photo-mixer to produce terahertz radiation that ranges from 0.8 to 2.51 THz at room temperature. This laser source can be modified into an all fiber-based THz generator by embedding ppLN crystals in a fiber filament configuration resulting in less absorption and producing high output power.

A light source based on an optical frequency mixer is disclosed. The light source has a first laser for emitting light at a first optical frequency, and a plurality of second lasers for emitting light at different second optical frequencies. The optical frequency mixer provides output light beams at mixed optical frequencies of the first and second lasers. Wavelength of output light beams may be tuned by tuning wavelength of any of the first or second lasers. In this manner, RGB wavelength-tunable light sources may be constructed based on red or near-infrared lasers. The wavelength tunability of the output light beams may be used to angularly scan or refocus the light beams.

An example system for inspecting a surface includes a laser, an optical system, a gated camera, and a control system. The laser is configured to emit pulses of light, with respective wavelengths of the pulses of light varying over time. The optical system includes at least one optical element, and is configured to direct light emitted by the laser to points along a scan line one point at a time. The gated camera is configured to record a fluorescent response of the surface from light having each wavelength of a plurality of wavelengths at each point along the scan line. The control system is configured to control the gated camera such that an aperture of the gated camera is open during fluorescence of the surface but closed during exposure of the surface to light emitted by the laser.

A Dense Wavelength Division Multiplexing (DWDM) photonic integration circuit (PIC) that implements a DWDM system, such as a transceiver, is described. The DWDM PIC architecture includes photonic devices fully integrating on a single manufacturing platform. The DWDM PIC has a multi-wavelength optical laser, a quantum dot (QD) laser with integrated heterogeneous metal oxide semiconductor (H-MOS) capacitor, integrated on-chip. The multi-wavelength optical laser can be a symmetric comb laser that generates two equal outputs of multi-wavelength light. Alternatively, the DWDM PIC can be designed to interface with a stand-alone multi-wavelength optical laser that is off-chip. In some implementations, the DWDM PIC integrates multiple optimally designed photonic devices, such as a silicon geranium (SiGe) avalanche photodetector (APD), an athermal H-MOS wavelength splitter, a QD photodetector, and a heterogenous grating coupler. Accordingly, fabricating the DWDM PIC includes a unique III-V to silicon bonding process, which is adapted for its use of SiGe APDs.

A method for controlling an electromagnetic radiation source to produce single mode operation having an optimized side-mode suppression ratio over a set 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 minimum side mode suppression ratio over the range of wavelengths. The set of parameter combinations define sub-paths for nearly arbitrary transitions 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.

A resonator is provided having a waveguide with a first boundary, a second boundary parallel to the first boundary, a first end, a second end, and a waveguide cavity at least partly between the first boundary and the second boundary. A first grating, having a period of distance a, is at the first boundary of the waveguide, and a second grating, having a period of distance a, is at the second boundary of the waveguide. The first and second boundaries are separated by a constant distance d. The first boundary may have a periodic profile aligned with a periodic profile of the second boundary. The periodic profile of the first boundary and the second boundary may be a sinusoidal profile, a square profile, or profile of another shape. The resonator may be suitable for use in a distributed feedback laser.