A method (900) includes a gain current (I.sub.GAIN) to an anode of a gain-section diode (D.sub.0) disposed on a shared substrate of a tunable laser (310), delivering a modulation signal to an anode of an Electro-absorption section diode (D.sub.2) disposed on the shared substrate of the tunable laser, and receiving a burst mode signal (330) indicative of a burst-on state or a burst-off state. When the burst mode signal is indicative of the burst-off state, the method includes sinking a sink current (I.sub.SINK) away from the gain current at the anode of the gain-section diode. When the burst mode signal transitions to be indicative of the burst-on state from the burst-off state, the method includes ceasing the sinking of the sink current away from the gain current and delivering an overshoot current (I.sub.OVER) to the anode of the gain-section diode.

An apparatus, and related method, relates generally to a fiber-optic sensing system. In such a system, fiber-optic sensors are in a rosette or rosette-like pattern. An optical circulator is coupled to receive a light signal from a broadband light source, to provide the light signal to the fiber-optic sensors, and to receive a returned optical signal from the fiber-optic sensors. A spectral engine is coupled to the optical circulator to receive the returned optical signal and configured to provide an output signal.

Absolute temperature measurements of integrated photonic devices can be accomplished with integrated bandgap temperature sensors located adjacent the photonic devices. In various embodiments, the temperature of the active region within a diode structure of a photonic device is measured with an integrated bandgap temperature sensor that includes one or more diode junctions either in the semiconductor device layer beneath the active region or laterally adjacent to the photonic device, or in a diode structure formed above the semiconductor device layer and adjacent the diode structure of the photonic device.

A light source includes a substrate with a first surface and an opposite second surface. An epitaxial layer is positioned on the first surface of the substrate. The light source also includes at least one light generator in the epitaxial layer positioned such that an optical signal transmitted thereby is directed toward the substrate. A diffuser is positioned on the second surface of the substrate, and at least one monitor photodetector is positioned in the epitaxial layer in an arrangement configured to receive a portion of the optical signal which is reflected by the diffuser. In one form, the light generator may include a vertical cavity surface emitting laser (VCSEL).

Integrated laser sources emitting multi-wavelengths of light with reduced thermal transients and crosstalk and methods for operating thereof are disclosed. The integrated laser sources can include one or more heaters and a temperature control system to maintain a total thermal load of the gain segment, the heater(s), or both of a given laser to be within a range based on a predetermined target value. The system can include electrical circuitry configured to distribute current to the gain segment, the heater(s), or both. The heater(s) can be located proximate to the gain segment, and the distribution of current can be based on the relative locations. In some examples, the central laser can be heated prior to being activated. In some examples, one or more of the plurality of lasers can operate in a subthreshold operation mode when the laser is not lasing to minimize thermal perturbations to proximate lasers.

A laser display system 100 is configured to increase the dynamic range of a laser diode by modulating an operating current applied to the laser diode based on a desired sequence of brightness levels and a temperature of the laser diode. In some embodiments, a measuring circuit measures a voltage of the laser diode at a given current, which indirectly indicates the temperature of the laser diode, thus obviating the need for a direct measurement of temperature. In addition, in some embodiments, the measuring circuit identifies a threshold current of the laser diode based on a range of current values at which values of the current multiplied by the derivative of the voltage against the current vary relatively rapidly. By compensating for temperature effects and identifying the threshold current, a driver of the laser diode more precisely controls light output of the laser diode across an increased dynamic range.

The present disclosure provides an automatic power control circuit and method, and a laser diode circuit comprising the automatic power control circuit. The automatic power control circuit comprises: a voltage measurement unit configured to obtain an indicative voltage at a specific measurement point and output the indicative voltage to a processor, wherein the indicative voltage is configured to indicate a forward voltage of a laser diode in laser emitting state; and the processor configured to output a pulse parameter control signal in response to change in the indicative voltage, wherein the pulse parameter control signal is used to control an adjustment for a pulse parameter of laser pulses of the laser diode, such that laser emission power is within a preset range, and wherein the pulse parameter of the laser pulses of the laser diode is used to set a total duration of pulses within a preset time period.

A device for managing power of a laser source in a laser-based apparatus includes switched-mode power controller circuitry. The power controller circuitry further includes a controller output configured to be coupled to reservoir capacitor of a laser source to provide a first mode of regulating charging of the reservoir capacitor between illuminations of the laser source and a second mode of regulating charging of the reservoir capacitor during illuminations of the laser source.

A light source includes a substrate with a first surface and an opposite second surface. An epitaxial layer is positioned on the first surface of the substrate. The light source also includes at least one light generator in the epitaxial layer positioned such that an optical signal transmitted thereby is directed toward the substrate. A diffuser is positioned on the second surface of the substrate, and at least one monitor photodetector is positioned in the epitaxial layer in an arrangement configured to receive a portion of the optical signal which is reflected by the diffuser. In one form, the light generator may include a vertical cavity surface emitting laser (VCSEL).

The laser assembly includes a semiconductor with an active semiconductor region, a controllable oscillator for generating a periodic electric signal that is applied to the semiconductor laser to generate a surface acoustic wave in or near the active semiconductor region such that a diffraction grating structure is created in or near the active semiconductor region by the surface acoustic wave, an emission wavelength of the active semiconductor region being determined by a periodicity of the diffraction grating structure, wherein the controllable oscillator is configured to set a frequency of the periodic electric signal in accordance with a control signal, and a control circuit for generating the control signal for the controllable oscillator in such a manner that a shift of the emission wavelength from heating of the active semiconductor region during emission of the optical signal is at least partially compensated by an opposite shift of the emission wavelength from a change of the periodicity of the diffraction grating structure in or near the active semiconductor region.