A device for measuring optical spectra at high speed and with high resolution using tunable optical laser comb sources. In one embodiment there is provided a first tunable comb laser source and a second tunable comb laser source whereby the wavelength of each comb laser source is chosen such that the combination of the two sources provides a continuous spectral coverage over a band in an optical spectrum under a selected wavelength tuning condition. By overlapping the two comb sources in the manner described the deadzone issue is overcome in the most spectrally efficient way possible.

An optical transmission system includes a laser module generating a modulated optical waveform, including both amplitude and frequency modulation, at center frequencies corresponding to different operating temperatures; and an optical shaping filter, with passbands corresponding to the different center frequencies, that converts at least part of the frequency modulation to additional amplitude modulation. The optical transmission system is tuned by: determining a range of temperatures at which the laser module center frequencies are within a passband of the optical shaping filter; setting the laser module to a temperature, within the range of temperatures, at which the modulated optical waveform is within the passband; measuring an average output power of the optical shaping filter; and adjusting the temperature of the laser module to a target temperature, within the range of temperatures, at which an output condition is achieved, based on the average output power and/or extinction ratio of the filtered waveform.

A time of flight (TOF) assembly includes a laser light source, one or more photo detectors and a detection circuit. The one or more photo detectors are configured to receive light and convert the received light into an electric signal. The detection circuit is configured to send a turning-off control signal to turn off the laser light source in response to the electric signal indicating that a time length, in which the laser light source is in an effective working state within a first duration, is greater than a preset time length threshold value or the electric signal indicating that energy of light emitted from the laser light source within a second duration is greater than a preset energy threshold. The disclosure also provides a terminal device and a control method for a TOF assembly.

This invention provides an accurate current mirror circuit in a low voltage headroom applied to common-anode laser drivers, including a reference current detection unit, a tail current source unit, and a control unit. The reference current detection unit generates a bias voltage and a reference voltage according to a reference current from the reference current source; the tail current source unit receives the bias voltage and generate a mirror current accordingly; the control unit receives the reference voltage and an output voltage corresponding to the mirror current and carry out a feedback regulation to the bias voltage accordingly. In this invention, the reference voltage and the output voltage are locked at same level, and then the bias voltage is mirrored to generate the mirror current outputted to the laser, thus avoiding the problem of inaccurate current output caused by the offset of the control unit in the low voltage headroom.

Embodiments of the invention relate to a method and apparatus for measuring at least one parameter that is (i) descriptive of stochastic motion of suspended particles within a fluid; and/or (ii) is a rheological property of the fluid or of the suspension; (iii) describes a concentration of suspended particles within the fluid; and/or (iv) is a diffusion coefficient of the suspended particles and/or (iv) is a viscosity of the fluid or of the suspension; and/or (v) is a food aging or spoilage parameter and/or (vii) is an in-vivo or in-vitro blood coagulation parameter.

Provided is an optical device including a radio frequency (RF) signal source configured to electrically provide an RF signal, a first diode configured to operate as a laser diode (LD) or an electro-absorption modulator (EAM) in response to the RF signal, a second diode configured to share an N region of the first diode, be serially connected to the first diode, and have a P region connected to a ground to operate as a capacitor for series push-pull operation with the first diode, and a resistor connected between the N region and the ground.

The disclosure provides an optical module, including a laser, the laser including a light emitting region and a modulation region, and light emitted by the light emitting region emitting toward the modulation region; a first driver circuit, the first driver circuit being connected to the light emitting region, so that the light emitting region emits light with adjusted optical power; and a second driver circuit, the second driver circuit being connected to the modulation region, so that the modulation region changes the optical power of the light emitted from the light emitting region.

An atomic oscillator includes a semiconductor laser, an atomic cell, a light receiving element, a first temperature control element, a heat transfer member, and a second temperature control element. The laser includes a resonator and an insulation layer disposed around the resonator. The resonator includes a first mirror layer, a second mirror layer, and an active layer disposed between the first mirror layer and the second mirror layer. The atomic cell is irradiated with light emitted from the semiconductor laser. In the atomic cell, an alkali metal atom is accommodated. The light receiving element detects intensity of light transmitted through the atomic cell and outputs a detection signal. The first temperature control element controls a temperature of the semiconductor laser. The heat transfer member is disposed in the insulation layer. The second temperature control element is controlled based on the detection signal and is connected to the heat transfer member.

A driver circuit configured to increase or decrease a drive current flowing to a light emitting element in accordance with an input signal, the driver circuit including: an output terminal configured to be electrically connected between a bias current source and the light emitting element, and configured to draw an output current inward; a shunt circuit configured to generate a first current in accordance with the input signal; and a waveform shaping circuit configured to detect a rising transition of a voltage of the output terminal and generate a second current based at least in part on a result of detection, wherein the first current and the second current constitute the output current, Wherein the first current increases when the input signal increases, and decreases when the input signal decreases, and wherein the voltage of the output terminal rises when the output current decreases.

An optical transmission system includes a laser module generating a modulated optical waveform, including both amplitude and frequency modulation, at center frequencies corresponding to different operating temperatures; and an optical shaping filter, with passbands corresponding to the different center frequencies, that converts at least part of the frequency modulation to additional amplitude modulation. The optical transmission system is tuned by: determining a range of temperatures at which the laser module center frequencies are within a passband of the optical shaping filter; setting the laser module to a temperature, within the range of temperatures, at which the modulated optical waveform is within the passband; measuring an average output power of the optical shaping filter; and adjusting the temperature of the laser module to a target temperature, within the range of temperatures, at which an output condition is achieved, based on the average output power and/or extinction ratio of the filtered waveform.