Time-of-flight (ToF) systems which use pulsed laser diodes, are required to measure distances with high level of precision and control. The present disclosure provides a method and a corresponding system for controlling a temporal response of a laser diode, in particular pulsed laser diodes. In particular, the present disclosure provides a method and a related system for driving a laser diode so as to obtain predominantly a peak pulse response while minimising or completely avoiding the post-peak response in a temporal response of the laser diode.

A laser apparatus includes a semiconductor laser element, a waveform calculation unit for calculating input waveform data, a driver circuit for supplying a drive current having a temporal waveform according to the input waveform data to the semiconductor laser element, an optical amplifier for amplifying laser light output from the semiconductor laser element, and a light waveform detection unit for detecting a waveform of laser light after the amplification output from the optical amplifier. The waveform calculation unit compares the waveform of the laser light after the amplification detected by the light waveform detection unit with a target waveform, adjusts a temporal waveform of the input waveform data, and brings the waveform of the laser light after the amplification close to the target waveform.

A tunable laser assembly housed in a single enclosure and a method of control is described wherein the tunable laser, pump and semiconductor optical amplifier do not share a common optical axis but are all aligned to optical waveguides on an intervening planar lightwave circuit (PLC). Wavelength monitoring circuitry is included on the PLC to enable monitoring and control of the tunable laser center wavelength and optical bandwidth. The design of the PLC does not introduce perturbations into the swept-source laser output spectrum that would cause artifacts in imaging applications such as optical coherence tomography (OCT).

A tunable laser assembly housed in a single enclosure and a method of control is described wherein the tunable laser, pump and semiconductor optical amplifier do not share a common optical axis but are all aligned to optical waveguides on an intervening planar lightwave circuit (PLC). Wavelength monitoring circuitry is included on the PLC to enable monitoring and control of the tunable laser center wavelength and optical bandwidth. The design of the PLC does not introduce perturbations into the swept-source laser output spectrum that would cause artifacts in imaging applications such as optical coherence tomography (OCT).

A light source device includes a laser diode configured to emit a laser light used as an illumination light, a determination unit configured to determine one of a plurality of modes as an operation mode of the laser diode based on usage state of the light source device; and a driver configured to drive the laser diode in a condition that a bias current to the laser diode is applied depending on the operation mode determined by the determination unit.

Apparatuses, methods, and systems for detecting a substance are disclosed. One system includes a light source, an optical cavity, a cavity detector, and a processor. The light source generates a beam of electro-magnetic radiation, wherein a wavelength of the beam of electro-magnetic radiation is tuned to operate at multiple wavelengths. The optical cavity receives the beam of electro-magnetic radiation, wherein the physical characteristics of the cavity define a plurality of allowed axial-plus-transverse electro-magnetic radiation modes, wherein only a subset of the allowed axial-plus-transverse electro-magnetic radiation modes are excited when the optical cavity receives the beam of electro-magnetic radiation. The cavity detector senses electro-magnetic radiation emanating from the optical cavity. The processor operates to receive information relating to the sensed electro-magnetic radiation, and detects the substance within the optical cavity based on amplitude and/or phase of the sensed electro-magnetic radiation emanating from the optical cavity.

A light emission apparatus includes a transistor comprising a control terminal, a first channel terminal, and a second channel terminal, wherein the control terminal is configured to receive a modulation signal, the first channel terminal is configured to generate a driving signal according to the modulation signal, and the second channel terminal is coupled to a fixed voltage; and a load comprising: a first terminal; a second terminal, wherein the first terminal is coupled to the first channel terminal of the transistor and the second terminal is coupled to the fixed voltage; a laser diode configured to emit a light according to the driving signal; and a first capacitor coupled to the laser diode, configured to isolate a DC current on the first terminal of the transistor.

The invention relates to a laser system comprising a laser light source (1) that emits laser radiation during operation of the laser system, a modulation means (2) that brings about modulation of the laser radiation emitted by the laser light source (1) such that the spectrum of the laser radiation comprises a carrier (14) and two sidebands (13, 15) that are symmetrically distributed around the carrier, and at least one optical amplifier (5) that amplifies the radiation emitted by the laser light source (1). The invention proposes that an optical filter (4) be provided in the beam path of the laser radiation, upstream of the optical amplifier (5), which filter is intended for removing the spectral portion of the laser radiation at the frequency of one of the two sidebands (13). The laser system is suitable inter alia for generating an artificial guide star (laser guide star) for astronomical telescopes comprising adaptive optics. The invention furthermore relates to a method for generating single-sideband modulated laser radiation.

An arrangement and a method are provided, wherein the arrangement is configured to prevent current pulses from reaching a laser diode, wherein the arrangement is configured to receive voltage required for its operation from a USB power source, and wherein the arrangement comprises: a capacitor configured to provide energy for the operation of the laser diode at times when high current pulses are required by a camera associated with the arrangement; a software configurable micro controller, operative to control functionality of the arrangement so as to prevent current pulses from reaching the laser diode; and a current source configured to provide current for the operation of the laser diode under safe conditions and to cease provisioning of that current when conditions are unsafe for the operation of the laser diode.

An embodiment pulse generator circuit is configured to apply a current pulse to two output terminals. The pulse generator circuit comprises an LC resonant circuit comprising an inductance and a capacitance connected in series between a first node and a negative input terminal. The pulse generator circuit comprises a charge circuit configured to charge the capacitance via a supply voltage, a first electronic switch configured to selectively short-circuit the two output terminals, a second electronic switch configured to selectively connect the two output terminals in parallel with the LC resonant circuit, and a control circuit configured to drive the first and the second electronic switch.