An optical module for preventing laser beam leakage and a control method thereof are disclosed. The optical module including a current control circuit, a first transistor, a laser, and a laser control unit. The laser control unit is configured to: if it is detected that an optical fiber is inserted in the optical fiber interface, perform control to turn on the laser, or if it is detected that no optical fiber is inserted in the optical fiber interface, control the laser to remain in an off state. A laser beam is effectively prevented from causing human bodily injury when an optical fiber is not inserted in an optical fiber interface.

Semiconductor laser device A1 includes semiconductor laser element 4, switching element 5 having gate electrode 52, source electrode 53 and drain electrode 54, and support member 1 having conductive part 3 that forms a conduction path to switching element 5 and semiconductor laser element 4 and supports semiconductor laser element 4 and switching element 5. Conductive part 3 has front surface first section 311 spaced apart from semiconductor laser element 4. Semiconductor laser device A1 includes at least one first wire 71 connected to source electrode 53 of switching element 5 and semiconductor laser element 4 and also at least one second wire 72 connected to source electrode 53 of switching element 5 and front surface first section 311 of conductive part 3. Such an arrangement reduces the inductance component of semiconductor laser device A1.

The invention describes a laser device (100) enabling controlled emission of individual laser beams (194). The laser device (100) comprises an optically pumped extended cavity laser with one gain element whereby a multitude of pump lasers (110) are provided in order to generate independent pump beams (191) and thus corresponding laser beams (194). The laser device (100) may be used to enable simplified or improved laser systems (500) as, for example, two or three-dimensional laser printers. The pump laser (110) may be VCSEL and the laser (160) may be a VECSEL monolithically integrated with the pump VCSEL array on the same substrate. Pump mirrors (140) and external cavity mirror (150) may be integrated into a single optical reflector with regions having different curvature. The laser emission is controlled by the pump light, i.e. transversal shape of the laser beam and/or number of laser beams is controlled by switching on/off the individual pump lasers (110).

In one example, an optical logic device includes a distributed feedback laser configured to generate a first signal corresponding to distributed feedback laser output signal, the first signal being at a first wavelength. The device further includes a bandpass filter having a center frequency corresponding to the first wavelength. Additionally, the device can include an optical circulator having a first port coupled to a logic device input signal, a second port coupled to the first signal, and a third port coupled to the bandpass filter, wherein when the logic device input signal has a power above a predetermined threshold and there is a wavelength difference between the first wavelength and an input wavelength of the logic device input signal, a suppression of the first signal occurs.

A laser structure comprising a first photonic crystal surface emitting laser (PCSEL), a second PCSEL, and a coupling region that extends between the first PCSEL and the second PCSEL along a longitudinal axis and that is electrically controllable so as to be capable of coherently coupling the first PCSEL to the second PCSEL. Each PCSEL include an active layer, a photonic crystal, and a two-dimensional periodic array distributed in an array plane parallel to the longitudinal axis within the photonic crystal where the two-dimensional periodic array is formed of regions having a refractive index that is different to the surrounding photonic crystal.

Structures for response shaping in frequency and time domain, include an optical response shaper and/or a modulator device with multiple injection. The device comprises a resonator having an enclosed geometric structure, for example a ring or racetrack structure, at least two injecting optical waveguides approaching the resonator to define at least two coupling regions between the resonator and the injecting waveguides, and may define at least two Free Spectral Range states. One or both of the coupling regions has a coupling coefficient selected for a predetermined frequency or time response, and the coupling coefficient or other device parameters may be variable, in some case in real time to render the response programmably variable. In addition, the injection power at one of the optical waveguides serves to modify the response.

Optical systems can emit train(s) of light pulses onto objects to derive a distance between the light source and the object. Achieving meter or centimeter resolution may require very short light pulses. It is not trivial to design a circuit that can generate narrow current pulses for driving a diode that emits the light pulses. An improved driver circuit has a pre-charge path comprising one or more inductive elements and a fire path comprising the diode. Switches in the driver circuit are controlled with predefined states during different intervals to pre-charge current in the one or more inductive elements prior to flowing current through the fire path to pulse the diode.

A laser system includes first and second mirrors, a semiconductor laser and a high frequency pulse generator. The semiconductor laser generates optical power within an optical cavity and reflects the optical power between the first mirror and second mirrors. The optical power has a frequency of f.sub.original-laser. The high frequency pulse generator generates a high frequency pulse with a rise time greater than an optical cycle of the optical power within the optical cavity and directly impinges the high frequency pulse on the optical power within the optical cavity. Impinging the high frequency pulse on the optical power within the optical cavity causes a frequency shift of the optical power to generate a final laser frequency that is greater than f.sub.original-laser as well as beyond a frequency band of the second mirror to cause a final laser to be emitted past the second mirror and from the semiconductor laser.

Devices, methods and techniques related to the use of a photoconductive semiconductor switch (PCSS) to drive a high-power laser diode for a wide range of pulse widths are disclosed. In one example aspect, a circuit for driving one or more laser diodes includes an input port configured to be coupled to a voltage input, one or more inductors that are configured to be in series with the one or more laser diodes, a photoconductive switch coupled with the one or more inductors, and an output port configured to be coupled to the one or more laser diodes.