A method and an apparatus for compensating for wavelength drift are disclosed. The method includes: generating, by a burst control circuit, a burst bias current; sending, by the burst control circuit, the burst bias current to a light emitting part and a trigger; converting, by the trigger, the received burst bias current into burst DA data; sending, by the trigger, the burst DA data to a synthesizer circuit; receiving, by the synthesizer circuit, the burst DA data sent by the trigger and the calibrated DA data sent by the MCU respectively; synthesizing, by the synthesizer circuit, the burst DA data and the calibrated DA data to obtain a synthesized signal; and sending, by the synthesizer circuit, the synthesized signal to a temperature control part.

The present invention relates to a driving device, a driving method, and a light-emitting unit that make it possible to appropriately drive a light-emitting element.

The driving device according to the present invention includes: a setting section (161) that sets at least one of a bias current of a light-emitting element (an LD 121) or a target current for setting output light from the light-emitting element (the LD 121) to desired intensity on the basis of a result of detection of an offset light amount when the light-emitting element (the LD 121) does not emit light; and an output controller (164) that controls an output of a driving current of the light-emitting element (the LD 121) on the basis of at least one of the set bias current or the set target current. The detection of the offset light amount is performed by a light-receiving element (a PD 122) that receives a portion of the output light.

The present invention is applicable to a ranging module, for example.

A transmitter unit for emitting radiation into the surrounding area, including at least one semiconductor laser, which has at least one first emitter possessing a first section and a second section; and at least one control unit for controlling the semiconductor laser. The control unit is configured to apply a first supply variable to the first section of the at least one emitter, and to apply a second supply variable differing from the first supply variable, to the second section of the at least one emitter.

A tunable laser is provided, including a first reflector, a second reflector, a phase adjustment area, a gain area, a first detector, a second detector, and a controller. The phase adjustment area is located between the first reflector and the gain area, the gain area is located between the phase adjustment area and the second reflector, a reflectivity of the first reflector is adjustable, and a reflectivity of the second reflector is adjustable. The first detector is configured to convert an optical signal of the first reflector into a first electrical signal. The second detector is configured to convert an optical signal of the second reflector into a second electrical signal. The controller is configured to adjust at least one of the reflectivity of the first reflector or the reflectivity of the second reflector based on the first electrical signal and the second electrical signal.

The present disclosure provides a unique digitally integrated, self-trained pre-distortion curve generation method and apparatus for semiconductor lasers (SCLs) to generate linearly swept optical signals that are applicable to a wide range of sweep velocities and semiconductor laser types. The method requires no prior knowledge of the frequency response of the laser and is highly accurate.

A driver circuit for a laser diode is configured to pass a current. The circuit includes a charge-pump configured to generate an output boosted positive supply rail voltage. At least one switch is configured to couple the output of the charge-pump to a terminal of the laser diode and to isolate the positive supply rail from the terminal of the laser diode when the charge-pump is enabled.

The disclosure provides a light source device and an image display device. The light source device includes a laser light source configured to emit laser light having a wavelength in a range from 635 nm to 645 nm inclusive, a temperature sensor configured to detect temperature around the light source device, and a laser control circuit configured to control the laser light source. The laser control circuit approximates, with use of a quartic expression, change in threshold current of the laser light source relative to temperature, and approximates, with use of a quadratic expression, change in slope efficiency of the laser light source relative to temperature, to obtain threshold current and slope efficiency of the laser light source corresponding to detection temperature of the temperature sensor, and controls the laser light source in accordance with the threshold current and the slope efficiency thus obtained.

The present invention relates to a driving device, a driving method, and a light-emitting unit that make it possible to appropriately drive a light-emitting element. The driving device according to the present invention includes: a setting section (161) that sets at least one of a bias current of a light-emitting element (an LD 121) or a target current for setting output light from the light-emitting element (the LD 121) to desired intensity on the basis of a result of detection of an offset light amount when the light-emitting element (the LD 121) does not emit light; and an output controller (164) that controls an output of a driving current of the light-emitting element (the LD 121) on the basis of at least one of the set bias current or the set target current. The detection of the offset light amount is performed by a light-receiving element (a PD 122) that receives a portion of the output light. The present invention is applicable to a ranging module, for example.

A method for detecting abnormality in a light emitting device including a semiconductor laser element that is pulse-driven by pulse-control to emit excitation light, a wavelength conversion member including a phosphor and that emits fluorescent light by being irradiated with the excitation light, and a light receiving element disposed on a light extraction side of the wavelength conversion member and that detects the excitation light, the method includes: pulse-controlling an applied voltage with a pulse width shorter than a time from a start of voltage application until an optical intensity of light extracted from the wavelength conversion member reaches a maximum intensity, thereby pulse-driving the semiconductor laser element to achieve laser oscillation; measuring an optical intensity of the excitation light, or optical intensities of both the excitation light and the fluorescent light; and determining whether or not the optical intensity or the optical intensities falls within a prescribed range.

A solid-state laser system includes: a first solid-state laser device configured to output a first pulse laser beam; a second solid-state laser device configured to output a second pulse laser beam; a first non-linear crystal disposed on a first optical path and configured to convert the first and second pulse laser beams into a third pulse laser beam and output the third pulse laser beam; and a second non-linear crystal disposed on a second optical path and configured to convert the second and third pulse laser beams into a fourth pulse laser beam and output the fourth pulse laser beam. The second pulse laser beam is incident on the second non-linear crystal at a first timing before the first non-linear crystal. Residual light of the second pulse laser beam is incident on the first non-linear crystal at a second timing later than the first timing.