Provided are a laser device and a method of transforming laser spectrum, which provide a laser frequency stabilization and significant narrowing a laser spectrum. A laser device includes at least one multiple longitudinal mode laser (L) for generating a laser light having a spectrum of multiple longitudinal modes; at least one high quality factor (high-Q) microresonator (M) optically feedback coupled to the at least one multiple longitudinal mode laser (L); and a tuner (TU) for tuning the spectrum of multiple longitudinal modes of the laser light. The laser device is configured to output an output laser light having an output spectrum with at least one dominant longitudinal laser mode each at a reduced linewidth of the dominant longitudinal laser mode. The laser device allows increasing an emission power of a narrow linewidth lasing without an additional amplification while keeping a compact size of a device with a limited number of optical elements.

The present invention relates to a device for generating laser radiation.

An object of the present invention is to indicate a laser diode which simultaneously has a high degree of efficiency and a low degree of far field divergence.

The diode laser according to the invention comprises a current barrier (5), characterized in that the current barrier (5) extends along a third axis (X), wherein the current barrier (5) has at least one opening, and a first width (W1) of the opening of the current barrier (5) along the third axis (X) is smaller than a second width (W2) of the metal p-contact (8) along the third axis (X).

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.

One feature pertains to an apparatus that includes apparatus that includes an evanescent field coupler having a first surface that evanescently couples light between the evanescent field coupler and an open dielectric resonator. The apparatus also includes a thin film coating covering at least a portion of the first surface of the evanescent field coupler. The thin film coating is specifically designed so that the thin film coating reflects light of a first wavelength.

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.

A multi-wavelength laser includes a reference wavelength-tunable laser, N−1 secondary wavelength-tunable lasers, N beam splitters, a phase modulator, and N−1 frequency difference detection apparatuses. The reference wavelength-tunable laser is connected to one beam splitter, the beam splitter includes two output ports, and one of the output ports is connected to the phase modulator. The phase modulator is separately connected to the N−1 frequency difference detection apparatuses. The N−1 secondary wavelength-tunable lasers one-to-one correspond to remaining N−1 beam splitters and the N−1 frequency difference detection apparatuses. The secondary wavelength-tunable laser is connected to a corresponding beam splitter, the corresponding beam splitter includes two output ports, and one of the output ports is connected to a corresponding frequency difference detection apparatus. N is a positive integer not less than 2. A multi-wavelength optical signal generated by the phase modulator has a precise frequency spacing.

The optical amplifier has an inhomogeneously broadened gain material capable of generating a plurality of ensemble gains. A first optical filter and a second optical filter are provided in the photonic integrated circuit. The apparatus has a first laser cavity which includes the optical amplifier, the first optical filter optically coupled to each other and at least two mirrors. The apparatus has a second laser cavity which includes the optical amplifier, the second optical filter optically coupled to each other and at least two mirrors. The first optical filter is tunable to a respective first ensemble gain generated by the optical amplifier and the second filter is tunable to a respective second ensemble gain generated by the optical amplifier; and the second ensemble gain is different from the first ensemble gain. A laser source and an optical transmitter are also disclosed.

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.

In one embodiment, a distributed feedback laser includes a laser comprising a waveguide, the waveguide having a variable width from a first end to a second end, the laser to generate optical energy of a plurality of lasing wavelengths. Other embodiments are described and claimed.

A tunable laser device is described. In one example, the tunable laser device includes an adaptive ring mirror, a gain waveguide, a loop mirror waveguide, and a booster amplifier waveguide. The gain waveguide and the boost amplifier waveguide can be formed in a semiconductor optical amplifier (SOA) region of the tunable laser device, and the adaptive ring mirror and the loop mirror waveguide can be formed in a silicon photonics region of the tunable laser device. The adaptive ring mirror includes a phase shifter optically coupled between a number of MMI couplers. By inducing a phase shift using the phase shifter, the wavelength of the output of the tunable laser device can be altered or adjusted for use in coherent fiber-optic communications, for example, among other applications.