Example implementations include a method of pre-bootup fault monitor of a LASER diode driver output, by applying a first power to a pre-bootup fault monitor device, setting a fault condition at the pre-bootup fault monitor device to a no-fault state, initiating the pre-bootup fault monitor device, determining whether a first impedance of driver output satisfies an impedance threshold, and in response to a determination that the first impedance satisfies the impedance threshold, applying a second power to the output device. Example implementations also include a system with a LASER output device, and a pre-bootup fault monitor device operatively coupled to the LASER output device, and operable to activate in response to receiving a first power, set a fault condition to a no-fault state, determine whether a first impedance of the output driver satisfies an impedance threshold, and, in response to a determination that the first impedance satisfies the impedance threshold, apply a second power to the LASER output device, and a power-on reset controller operatively coupled to the pre-bootup fault monitor and operable to, in response to the determination that the first impedance satisfies the impedance threshold, deactivate the pre-bootup fault monitor.

A fiber optic voltage conditioner, and method therefor, generally relate to voltage conditioning. In such a fiber optic voltage conditioner, there is a laser, and an optical circulator is coupled to receive a light signal from the laser. A controller is coupled to the laser and is configured to generate first control information for wavelength-drift control of the laser. A data acquisition module is coupled to the controller and is configured to generate second control information for the controller for adjustment of the first control information. A photodetector is coupled to the optical circulator to receive a returned optical signal and is coupled to the data acquisition module to provide an analog output signal thereto. The photodetector is configured to generate the analog output signal responsive to the returned optical signal. The data acquisition module is configured to generate the second control information using the analog output signal.

A method and apparatus provide for determining a temperature at a junction of a laser diode when the laser diode is operated in a lasing state that facilitates heat-assisted magnetic recording, comparing the junction temperature and an injection current supplied during the lasing state to stored combinations of junction temperature and injection current, and determining a likelihood of mode hopping occurring for the laser diode during the lasing state based on the comparison to stored combinations of junction temperature and injection current.

A light emission control device includes: a first light emission control circuit outputting a first control signal and a second control signal; and a second light emission control circuit outputting a third control signal and a fourth control signal. The first light emission control circuit controls a phase of the second control signal based on a first PWM signal in a first PWM dimming mode. The second light emission control circuit controls a phase of the fourth control signal based on a second PWM signal in a second PWM dimming mode. The second light emission control circuit outputs the fourth control signal having a phase different from that of the second control signal in a first analog dimming mode and a second analog dimming mode.

A fiber optic voltage conditioner, and method therefor, generally relate to voltage conditioning. In such a fiber optic voltage conditioner, there is a laser, and an optical circulator is coupled to receive a light signal from the laser. A controller is coupled to the laser and is configured to generate first control information for wavelength-drift control of the laser. A data acquisition module is coupled to the controller and is configured to generate second control information for the controller for adjustment of the first control information. A photodetector is coupled to the optical circulator to receive a returned optical signal and is coupled to the data acquisition module to provide an analog output signal thereto. The photodetector is configured to generate the analog output signal responsive to the returned optical signal. The data acquisition module is configured to generate the second control information using the analog output signal.

Example implementations include a method of pre-bootup fault monitor of a LASER diode driver output, by applying a first power to a pre-bootup fault monitor device, setting a fault condition at the pre-bootup fault monitor device to a no-fault state, initiating the pre-bootup fault monitor device, determining whether a first impedance of driver output satisfies an impedance threshold, and in response to a determination that the first impedance satisfies the impedance threshold, applying a second power to the output device. Example implementations also include a system with a LASER output device, and a pre-bootup fault monitor device operatively coupled to the LASER output device, and operable to activate in response to receiving a first power, set a fault condition to a no-fault state, determine whether a first impedance of the output driver satisfies an impedance threshold, and, in response to a determination that the first impedance satisfies the impedance threshold, apply a second power to the LASER output device, and a power-on reset controller operatively coupled to the pre-bootup fault monitor and operable to, in response to the determination that the first impedance satisfies the impedance threshold, deactivate the pre-bootup fault monitor.

The present disclosure provides a mobile terminal and a system for controlling a laser projector. The system includes a first drive circuit, a second drive circuit, a microprocessor coupled to the first drive circuit, and an application processor. The first drive circuit is configured to output an electrical signal to the laser projector. The second drive circuit is configured to supply power to the first drive circuit. The application processor is configured to, read a preset signal from the microprocessor, and power off the second drive circuit to power off the first drive circuit and the laser projector, or send a reset signal for restarting the microprocessor to the microprocessor, in response to that the application processor cannot read the preset signal.

A light source device according to an embodiment includes: a first resistor (101) that is connected to a given potential; a light emitting element (12) that is connected in series to the first resistor; a second resistor (102) that is connected to the given potential; and a first current source (104) that is connected in series to the second resistor and that is configured to supply a freely-selected current within a given range are included. A first voltage is taken out from a first connection part where the first resistor and the light emitting element are connected to each other and a second voltage is taken out from a second connection part where the second resistor and the first current source are connected to each other.

A laser mount assembly includes a lens holder including a collimating lens. A laser subassembly is positioned adjacent the lens holder and includes a vertical-cavity surface-emitting laser, a thermal electric cooler, and a thermistor. A printed circuit board is positioned adjacent the laser subassembly and includes a plurality of heating components. The heating components heat the area between the lens holder and the laser subassembly.

In one embodiment, an electro-absorption modulator is configured to receive an optical light from an optical light source and outputs a modulated optical signal. The electro-absorption modulator includes a bias voltage that is used to set optimum predetermined modulation performance and an output power of the electro-absorption modulator. A controller is configured to measure a bias current of the optical light source and use a change of the bias current to determine a detuning change that occurs between the electro-absorption modulator and the optical light source. The controller uses the detuning change to automatically control the bias voltage of the electro-absorption modulator to maintain the predetermined modulation performance and maintain the output power of the electro-absorption modulator.