A system and method for providing laser diodes with broad spectrum is described. GaN-based laser diodes with broad or multi-peaked spectral output operating are obtained in various configurations by having a single laser diode device generating multiple-peak spectral outputs, operate in superluminescene mode, or by use of an RF source and/or a feedback signal. In some other embodiments, multi-peak outputs are achieved by having multiple laser devices output different lasers at different wavelengths.

A laser device includes a laser and a controller. The laser has an optical cavity that includes an active gain section and a phase shifter. The controller is configured to excite the active gain section to lase light out of the optical cavity. The controller is further configured to, while the light is being lased out of the optical cavity, modulate a refractive index of the phase shifter to shift an optical phase of lasing modes of the lased light to thereby reduce coherence of the lased light.

A laser driving circuit, a laser driving method, and a device using laser light that can reduce speckle noise caused by laser light as coherent light are provided. In the laser driving circuit that generates laser driving current for driving a plurality of laser light sources emitting laser light of different wavelengths on the basis of an input video signal, a high-frequency signal of a frequency exceeding the band of the video signal is superimposed on the laser driving current generated on the basis of the input video signal, whereby speckle noise caused by the laser light as coherent light is reduced.

A circuit is provided for generating a modulated laser diode control signal from a laser diode control signal, the circuit having an RF modulator for modulating the laser diode control signal with a modulation signal; the circuit having adjustment means for adjusting the RF modulator; the adjustment means being configured or configurable as a function of at least one laser diode operating information item. Furthermore, a laser diode receptacle is described as having such a circuit, a projector, particularly an image projector having such a laser diode receptacle, an image projector having such a laser diode receptacle and a laser diode, as well as a method for adjusting an RF modulator of such a circuit and a method for producing such a laser diode receptacle.

A method of designing a semiconductor laser device includes: controlling a distance between the output-side reflection unit and the second reflection unit and an effective optical feedback to the semiconductor laser element, the effective optical feedback defined by a below-presented formula (1) including a circulating time of the light in the semiconductor laser element, a reflectivity R.sub.1 of the output-side reflection unit, and a reflectivity R.sub.2 of the second reflection unit; selecting a semiconductor laser device in which an LFF period is equal to or smaller than 20 ns as a semiconductor laser device in which high speed switching occurs between an FBG mode and an FP mode; and using the selected semiconductor laser device as an semiconductor laser device oscillating in a coherent collapse mode.
=(1/)(1R.sub.1)(R.sub.2/R.sub.1).sup.1/2(1)

A process and system for producing random numbers by means of a quantum random number generator is disclosed, comprising the steps of operating a multimode laser in a laser cavity with periodic modulation of a net gain, and detecting the random intensity pattern produced by the inter-mode beating occurring within the laser cavity. The numbers produced are truly random and a minimal number of elements is required for operating the system.

A process and system for producing random numbers by means of a quantum random number generator is disclosed, comprising the steps of operating a multimode laser in a laser cavity with periodic modulation of a net gain, and detecting the random intensity pattern produced by the inter-mode beating occurring within the laser cavity. The numbers produced are truly random and a minimal number of elements is required for operating the system.

A laser driving circuit, a laser driving method, and a device using laser light that can reduce speckle noise caused by laser light as coherent light are provided.

In the laser driving circuit that generates laser driving current for driving a plurality of laser light sources emitting laser light of different wavelengths on the basis of an input video signal, a high-frequency signal of a frequency exceeding the band of the video signal is superimposed on the laser driving current generated on the basis of the input video signal, whereby speckle noise caused by the laser light as coherent light is reduced.

UV laser devices, systems, and methods are shown and/or described herein. Included are a method, device or system for VECSEL and MECSEL lasers including both barrier-pumped and in-well pumped lasers. Also disclosed is a method of manufacturing gain chips for use in the lasers, arrangements of lasers, and selection of proper non-linear crystal (NLC) for use in the device.

A method for producing wideband visible laser light wavelengths using planar photonic circuit elements for use in illuminating flat panel displays is shown.