Systems and methods described herein are directed to optical light sources, such as an external cavity laser (ECL) with an active phase shifter. The system may include control circuitry for controlling one or more parameters associated with the active phase shifter. The phase shifter may be a p-i-n phase shifter. The control circuitry may cause variation in a refractive index associated with the phase shifter, thereby varying a lasing frequency of the ECL. The ECL may be configured to operate as a light source for a light detection and ranging (LIDAR) system based on generating frequency modulated light signals. In some embodiments, the ECL may generate an output LIDAR signal with alternating segments of increasing and decreasing chirp frequencies. The ECL may exhibit increased stability and improved chirp linearities with less dependence on ambient temperature fluctuations.

A laser device includes a seed laser, a plurality of optical amplifiers, and an optical distribution assembly. The seed laser is configured to emit seed laser light. The plurality of optical amplifiers is configured to generate amplified laser light by amplifying the seed laser light. The optical distribution assembly is configured to distribute the seed laser light to an input of each of the optical amplifiers in the plurality and each of the optical amplifiers is configured to direct its respective amplified laser light to a common target.

A Vertical Cavity Surface Emitting Laser VCSEL, includes an optical resonator with a first reflector, a second reflector, and an active region for laser emission arranged between the first reflector and the second reflector and remaining regions outside of the active region, and an electrical contact arrangement configured to provide an electrical drive current to electrically pump the optical resonator. The optical resonator further comprises a loss layer introducing optical and/or electrical losses to increase wavelength shift of the laser emission when varying the drive current. If the loss layer is an optical loss layer, the optical losses introduced by the loss layer are higher than the sum of the optical losses in the remaining regions. If the loss layer is an electrical loss layer, the electrical losses introduced by the loss layer are higher by a factor of at least 5 than the electrical losses in the remaining regions.

The invention relates to a laser light source (10), comprising an arrangement (120) of surface-emitting semiconductor lasers (1251, 1252, . . . 125n) to which a voltage is applied such that an operating current is below the threshold current and an intrinsic emission of the surface-emitting semiconductor laser is prevented. The laser light source also comprises a first semiconductor laser (100) which emits radiation (110) that enters the surface-emitting semiconductor laser such that induced emission takes place via the injection locking mechanism and the individual surface-emitting semiconductor lasers emit laser light having the same wavelength and polarisation direction as the irradiated radiation (110). The emission frequency of the first semiconductor laser can be changed by changing the operating current.

A device for measuring optical spectra at high speed and with high resolution using tunable optical laser comb sources. In one embodiment there is provided a first tunable comb laser source and a second tunable comb laser source whereby the wavelength of each comb laser source is chosen such that the combination of the two sources provides a continuous spectral coverage over a band in an optical spectrum under a selected wavelength tuning condition. By overlapping the two comb sources in the manner described the deadzone issue is overcome in the most spectrally efficient way possible.

A method for tuning the frequency of THz radiation is provided. The method utilizes an apparatus comprising a spin injector, a tunnel junction coupled to the spin injector, and a ferromagnetic material coupled to the tunnel junction. The ferromagnetic material comprises a Magnon Gain Medium (MGM). The method comprises the step of applying a bias voltage to shift a Fermi level of the spin injector with respect to the Fermi level of the ferromagnetic material to initiate generation of non-equilibrium magnons by injecting minority electrons into the Magnon Gain Medium. The method further comprises the step of tuning a frequency of the generated THz radiation by changing the value of the bias voltage.

An apparatus includes a wavelength-tunable laser and an electronic controller. The electronic controller is configured to control the wavelength-tunable laser such that an output wavelength of the wavelength-tunable laser performs a zigzag in time. The wavelength-tunable laser is capable of rapidly and densely scanning wavelengths across a broad spectral range.

A tuning arrangement for a vertical-cavity surface-emitting laser (VCSEL) may include a delta sigma modulator and a current source. The delta sigma modulator may be configured to generate a bitstream comprising bit signals, and the current source may be configured to provide a current to the VCSEL in a switchable manner depending on a control signal. The bitstream is generated based on a target state signal and the control signal corresponds to or is derived from the bit signals of the bitstream.

A seed laser is configured to emit seed laser light. A plurality of optical amplifiers is configured to generate amplified laser light by amplifying the seed laser light. Each of the optical amplifiers is configured to separately direct its respective amplified laser light to a medium without being optically combined within the laser assembly with any of the other amplified laser light emitted by other optical amplifiers in the plurality of optical amplifiers.

Improved optical coherence tomography systems and methods to measure thickness of the retina are presented. The systems may be compact, handheld, provide in-home monitoring, allow the patient to measure himself or herself, and be robust enough to be dropped while still measuring the retina reliably.