A wavelength stabilizer that performs wavelength stabilization using thermal characteristics of a laser diode without using additional components such as an etalon filter, and an optical module including the wavelength stabilizer, are proposed. The wavelength stabilizer for the optical module stabilizes the wavelength of laser light outputted from the laser diode and includes a controller constantly maintaining a junction temperature of the laser diode. The controller may constantly maintain the junction temperature of the laser diode through a thermoelectric cooler.

A laser device includes: a light source including laser diodes; a processor that holds: a maximum current value of a driving current applied to the laser diodes, and a maximum power value of a power of light emitted from the light source; and a memory, coupled to the processor, that stores a relationship between a magnitude of the driving current, a magnitude of the power of the light, and a degree of deterioration of the light source. The processor further refers to the memory and estimates the degree of deterioration from the maximum current value and the maximum power value.

Methods and apparatus for a controlling a stimulus source to direct photons to a pixel in a pixel array contained in a detector system, analyzing a response of the pixel in the pixel array; and generating an alert based on the response of the pixel in the pixel array. Example stimulus sources include a conductive trace, a PN junction, and a current source.

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.

A method for physical random number generation includes the steps of: modulating the gain of a vertical-cavity surface-emitting laser periodically from the lower threshold to the upper threshold and back; maintaining the gain per round trip positive for a longer period than the round trip time of the cavity; maintaining the net gain per round trip negative for a longer period than the round trip time of the cavity, in order to create optical pulses of random amplitude; detecting the optical pulses; converting the optical pulses into electrical analog pulses; and digitising the electrical analog pulses into random numbers.

A method for correcting a wavelength and a tuning range of a laser spectrometer in which the light from a wavelength-tunable laser diode, after being radiating through a gas, is detected and evaluated, wherein the laser diode is periodically driven with a current ramp, such that a time-resolved absorption spectrum of the gas is obtained upon the detection of the light, where in order to correct the wavelength and the tuning range of the laser spectrometer, a first step involves readjusting the central wavelength of the laser diode via the temperature thereof and based on the position of one of two different selected absorption lines in the detected absorption spectrum, and a second step involves correcting the tuning range of the laser diode via the gradient of the current ramp such that the spacing of the two absorption lines in the detected absorption spectrum remains constant.

Multi-section laser systems are configured with a gain/modulation section and a pre-bias section. Both sections are electrically connected to a diode laser resonator and both sections are independently controllable via laser driver circuitry. The multi-section laser can be used to provide pulsing optimizations that include reducing the turn-on delay of the laser while also ensuring that the resulting laser light's spectral linewidth satisfies a threshold linewidth requirement. During use, a pre-bias current is applied to the pre-bias section. This current causes some photons to be spontaneously emitted. During this time, a gain current is refrained from being applied to the gain section until the resonator is seeded with a spectrum of photons from the pre-bias section. Once the resonator is sufficiently seeded, the gain current is applied to the gain section, thereby producing a seeded pulse of laser light having a desired spectral linewidth.

A photodiode current comparison circuit has a first current source coupled to a circuit node configurable to operate in a first mode, a second current source coupled to the circuit node configurable to operate in a second mode opposite the first mode, and a third current source switchable to route a current to the circuit node in response to a data signal using a transistor coupled between the circuit node and the third current source. A photodiode is coupled to the circuit node. In a first configuration, an anode of the photodiode is coupled to the circuit node and a cathode of the photodiode is coupled to a power supply terminal. In a second configuration, a cathode of the photodiode is coupled to the circuit node and an anode of the photodiode is coupled to a power supply terminal. An amplifier provides an error signal of the photodiode.

A control device, which controls a laser scanning display device, includes a laser device, a first current source that generates a first driving current supplied to the laser device, a second current source that generates a second driving current supplied to the laser device, and a controller. The controller controls the first current source to generate the first driving current having a first set current value that is 1/n times a threshold current value at a time when oscillation of the laser device starts, when scanning a non-display area in which no image is displayed, where n is a number greater than 1. The controller controls the second current source to generate the second driving current having a second set current value that is zero or greater and less than 11/n times the threshold current value, when scanning the non-display area.

A life prediction method for an optical module that keeps optical output constant by controlling a bias current that is applied to a laser diode includes, by a life prediction device: acquiring a current value of the bias current from the optical module; holding an initial bias current value that is an initial current value of the bias current; calculating the number of digits of a difference value between the bias current value and the initial bias current value, and determining whether there is an increase in the number of digits; calculating a time interval at which occurrence of the increase in the number of digits is detected; and estimating a life of the optical module using the time interval, a first threshold, and the number of digits.