The disclosure relates to multifunctional sensors for mobile applications, namely to a miniature optical sensor for remote micro- and macro-object detection and characterization. The disclosure makes it possible to reduce the size of the sensor, this provides for surface mount of the sensor in any microcircuit of a mobile device. The sensor is multifunctional, low-power, vibration-resistant. The sensor comprises at least one pair consisting of a radiation source and a corresponding radiation receiver, an optical circuit including a collimating element, a first optical element, a second optical element. The first optical element and the second optical element are interconnected by a common surface, the common surface being a semitransparent surface. The sensor may be used simultaneously as a microphone, a dust sensor, a lidar, and a photoplethysmogram (PPG) sensor.

A packaged transmitter device includes a base member comprising a planar part mounted with a thermoelectric cooler, a transmitter, and a coupling lens assembly, and an assembling part connected to one side of the planar part. The device further includes a circuit board bended to have a first end region and a second end region being raised to a higher level. The first end region disposed on a top surface of the planar part includes multiple electrical connection patches respectively connected to the thermoelectric and the transmitter. The second end region includes an electrical port for external connection. Additionally, the device includes a cover member disposed over the planar part. Furthermore, the device includes a cylindrical member installed to the assembling part for enclosing an isolator aligned to the coupling lens assembly along its axis and connected to a fiber to couple optical signal from the transmitter to the fiber.

Disclosed is a device for interaction between a laser beam and a hyperfine energy transition of a chemical species. The device further includes an electro-optic modulator with a single sideband with an input optical waveguide suitable for receiving a source laser beam and an output optical waveguide suitable for generating an output laser beam and an electronic system suitable for generating and applying, simultaneously, a first modulated electrical signal, sin(Ω.sub.1t)) to a first hyperfrequency pulse on a first high-frequency electrode of the electro-optic modulator and, respectively, another modulated electrical signal, cos(Ω.sub.1t)) to the first pulse on another high-frequency electrode of the electro-optic modulator, in such a way as to frequency-switch the output laser beam to a first optical frequency offset from the first pulse with respect to the initial optical frequency.

Discretely tunable laser systems include a continuously tunable laser for outputting a beam tunable among selectable frequencies, the selectable frequencies are separated in frequency by discrete frequency intervals, the discrete frequency intervals include a maximum interval and a minimum interval, where a difference between the maximum interval and the minimum interval is 100 MHz or less, and an external stabilization circuit coupled to the continuously tunable laser and a controller. The external stabilization circuit includes a first photodiode generating a first signal corresponding to a portion of the beam and an interferometer that produces resonances upon incidence of another portion of the beam. The resonances are equally spaced in frequency, with each defining one of the selectable frequencies. A second photodiode generates a second signal corresponding a transmission beam generated by the interferometer. The controller tunes the continuously tunable laser among the selectable frequencies based on the first and second signals.

A laser chip includes a first power detector, a first controller, an optical splitter, a polarization splitter-rotator, a bandpass filter, and a slave laser. The optical splitter includes a first, a second, and a third port. The first port is configured to receive injection light of a master laser. The second port is connected to the first power detector. The optical splitter is configured such that the injection light enters the optical splitter through the first port, and is output to the polarization splitter-rotator through the third port. The polarization splitter-rotator is configured to perform optical splitting and polarization conversion on the injection light. The polarization splitter-rotator includes a first waveguide configured to transmit TE mode injection light after the injection light is split by the polarization splitter-rotator, and a second waveguide configured to transmit TM mode injection light after the injection light is split by the polarization splitter-rotator.

A quantum cascade laser element includes: a semiconductor substrate; a semiconductor laminate including an active layer and having a first end surface and a second end surface facing each other in an optical waveguide direction; a first electrode; a second electrode; and an anti-reflection film formed on the first end surface. The semiconductor laminate is configured to oscillate laser light having a central wavelength of 7.5 μm or more. The anti-reflection film includes at least one of at least one layer of a CeO.sub.2 film formed by continuous sputtering and vacuum evaporation and a plurality of layers of CeO.sub.2 films formed by discrete sputtering and vacuum evaporation.

An on-chip ultra-narrow linewidth laser and a method for obtaining a single-longitudinal mode ultra-narrow linewidth optical signal are provided in the present invention. The on-chip ultra-narrow linewidth laser includes a laser generating gain unit for generating a broad-spectrum initial optical signal and performing wavelength filtering on the generated optical signal, and also includes a distributed scattering feedback unit for performing linewidth compression on the optical signal; the laser generating gain unit is connected with the distributed scattering feedback unit, so that the optical signal generated by the laser generating gain unit is subjected to wavelength filtering and then output to the light guide component of the distributed scattering feedback unit to scatter to form an optical signal with a narrower linewidth to achieve linewidth compression, and the optical signal returning along the original path and fed back to the optical signal of the laser generating gain unit is subjected to gain amplification and wavelength filtering once again, repeating until achieving a steady state so as to obtain a single-longitudinal mode ultra-narrow linewidth optical signal. The laser can obtain a steady single-longitudinal mode ultra-narrow linewidth optical signal, and is simple in structure and small in volume.

Frequency modulated lasers, LIDAR systems, and methods of controlling laser are disclosed. A laser source emits an optical beam having an optical frequency that changes in response to a signal applied to an input of the laser source. A laser driver that generates the signal applied to the input to cause the optical frequency to vary in accordance with a periodic frequency versus time function. The laser driver generates the signal for a current period of the periodic frequency versus time function based, at least in part, on optical frequency versus time measurements of one or more prior periods of the periodic frequency versus time function.

Disclosed is a device for interaction between a laser beam and a hyperfine energy transition of a chemical species. The device further includes an electro-optic modulator with a single sideband with an input optical waveguide suitable for receiving a source laser beam and an output optical waveguide suitable for generating an output laser beam and an electronic system suitable for generating and applying, simultaneously, a first modulated electrical signal, sin(Ω.sub.1t)) to a first hyperfrequency pulse on a first high-frequency electrode of the electro-optic modulator and, respectively, another modulated electrical signal, cos(Ω.sub.1t)) to the first pulse on another high-frequency electrode of the electro-optic modulator, in such a way as to frequency-switch the output laser beam to a first optical frequency offset from the first pulse with respect to the initial optical frequency.

An optical module includes: an optical element; and a thermoelectric module on which the optical element is mounted. Further, the thermoelectric module includes a first substrate, a second substrate disposed to face the first substrate, and a plurality of thermoelectric elements provided between the first substrate and the second substrate, and a pattern made of a material different from a material of the first substrate is formed on a surface of the first substrate opposite to a back surface of the first substrate facing the second substrate, and the optical element is mounted on the surface of the first substrate in association with the pattern.