Abstract: The present invention provides methods and an apparatus for monitoring the optical output power of a laser diode (LD) having an associated photodiode (PD), and a particle sensor apparatus. The photodiode (PD) is operable together with the laser diode (LD), wherein it detects the light (LS) of the laser diode (LD) and converts it into an electrical current, and is thermally coupled to the laser diode (LD). Monitoring of the optical output power P is effected during the operation of the laser diode (LD) and is based on current measurements and/or voltage measurements at the laser diode (LD) and at the photodiode (PD).

Abstract: A vertical cavity surface emitting laser device includes: an optical resonator; a photodiode; and a contact arrangement. The optical resonator includes: two distributed Bragg reflectors (DBRs) and an active region between the DBRs. The photodiode has a light absorption region in the optical resonator. The contact arrangement provides drive current to pump the optical resonator, and contacts the photodiode. The active region has an InxGa1-xAs layer, where 0?x<1. The light absorption region has an InyGa1-yAs layer, where 0<y<1, and y>x. The InyGa1-yAs layer is an intrinsic layer of the light absorption region. The InyGa1-yAs layer is 15-50 nm thick. The light absorption region has an undoped layer with a material different from the InyGa1-yAs layer. The InyGa1-yAs layer is immediately adjacent to the undoped layer. An intrinsic zone of the light absorption region is at least 70 nm thick.

Abstract: The present invention provides a method for estimating a condition parameter of a laser diode having an associated photodiode, to an apparatus for monitoring the operation of such a laser diode, and to a particle sensor apparatus. The photodiode (PD) is operable together with the laser diode (LD), wherein it detects the light (LS) of the laser diode (LD) and converts it into an electrical current, and is thermally coupled to the laser diode (LD). The at least one condition parameter is estimated during the operation of the laser diode (LD) and the estimation is based on current measurements and/or voltage measurements at the laser diode (LD) and/or at the photodiode (PD).

Abstract: A laser device includes a laser diode configured to emit radiation, an output power of the radiation being dependent on a laser diode driving current, and a photodiode configured to receive the radiation emitted by the laser diode. A photodiode current induced in the photodiode by the received radiation is dependent on a power of the received radiation. The laser device further includes circuitry configured to measure the photodiode current for a laser diode driving current and calculate a laser threshold current of the laser diode from the measured photodiode current as a measure of an actual laser threshold current of the laser diode. The circuitry is further configured to detect a malfunction or degradation of the laser diode.

Abstract: The present invention provides an optical fire sensor device and a corresponding fire detection method. The optical fire sensor device is equipped with an optical particle detection unit (10), which is configured to ascertain measured values of a particle number in a measurement volume range (FA) as a function of a particle size in a predetermined particle size range and/or as a function of a particle speed in a predetermined particle speed range, a fire detection unit (20), which is configured to ascertain respective distributions of the measured values and to compare at least one parameter of the ascertained distributions to at least one predetermined criterion. The fire detection unit (20) is configured to detect a fire (B) in consideration of the comparison. An alarm unit (30, 40) is used to output an alarm signal in response to the detection of the fire (B) by the fire detection unit (20).

Abstract: The present invention provides an optical fire sensor device and a corresponding fire detection method. The optical fire sensor device is equipped with an optical particle detection unit (10), which is configured to ascertain measured values of a particle number in a measurement volume range (FA) as a function of a particle size in a predetermined particle size range and/or as a function of a particle speed in a predetermined particle speed range, a fire detection unit (20), which is configured to ascertain respective distributions of the measured values and to compare at least one parameter of the ascertained distributions to at least one predetermined criterion. The fire detection unit (20) is configured to detect a fire (B) in consideration of the comparison. An alarm unit (30, 40) is used to output an alarm signal in response to the detection of the fire (B) by the fire detection unit (20).

Abstract: The present invention provides a method for estimating a condition parameter of a laser diode having an associated photodiode, to an apparatus for monitoring the operation of such a laser diode, and to a particle sensor apparatus. The photodiode (PD) is operable together with the laser diode (LD), wherein it detects the light (LS) of the laser diode (LD) and converts it into an electrical current, and is thermally coupled to the laser diode (LD). The at least one condition parameter is estimated during the operation of the laser diode (LD) and the estimation is based on current measurements and/or voltage measurements at the laser diode (LD) and/or at the photodiode (PD).

Abstract: The present invention provides methods and an apparatus for monitoring the optical output power of a laser diode (LD) having an associated photodiode (PD), and a particle sensor apparatus. The photodiode (PD) is operable together with the laser diode (LD), wherein it detects the light (LS) of the laser diode (LD) and converts it into an electrical current, and is thermally coupled to the laser diode (LD). Monitoring of the optical output power P is effected during the operation of the laser diode (LD) and is based on current measurements and/or voltage measurements at the laser diode (LD) and at the photodiode (PD).