Abstract:
The invention describes a laser device (10) comprising an array (50) of laser emitters (100) and a control unit (200), the array (50) comprises at least a first sub array (110) of laser emitters and a second sub array (120) of laser emitters, wherein the first sub array (110) emits laser light of a first polarization and the second sub array (120) emits laser light of a second polarization being different from the first polarization, and wherein the control unit (200) is adapted to control the first sub array (110) and the second sub array (120) such that the polarization of the laser light emitted by the array (50) can be changed. The invention further describes a sensor device (300) and an optical detection system (400) comprising such a laser device (10). Furthermore, a method of determining the shape of an object by means of the optical detection system (400) is described.
Abstract:
The invention provides a system and a method for wavelength referencing and polarization mitigation. An optical wavelength tunable laser source is swept in a number of contiguous, overlapping sweep segments. A coarse reference wavelength section produces a reference signal that defines at least one absolute wavelength within a sweep segment. A fine wavelength reference section produces a periodic wavelength reference signal that defines a plurality of equidistant wavelengths within each sweep segment with an indeterminate offset relative to the absolute wavelength(s) of the coarse reference wavelength section. The free spectral range of the fine wavelength reference section is smaller than the spacing between subsequent absolute reference wavelengths of the coarse reference wavelength section. This arrangement allows reducing the minimum required overlap between contiguous sweep segments.
Abstract:
Tunable external cavity lasers are used in applications such as interferometry, FM spectroscopy, and optical communications equipment testing. Mode hop free high bandwidth frequency modulation operation is desired in a tunable external cavity laser. This application describes new and novel techniques for controlling the output wavelength of a tunable external cavity laser while suppressing mode hop.
Abstract:
A method and apparatus are provided for stabilizing a distributed feedback semiconductor laser (12). The method includes the steps of comparing an optical output of a first oscillating mode of the semiconductor laser (12) at a first polarization angle with an optical output of a second oscillating mode of the semiconductor laser at a second polarization angle orthogonal to the first polarization angle. A first feedback signal is provided to a cavity temperature controller of the semiconductor laser in response to detected differences of the compared first and second oscillating modes. The method further includes the step of comparing an output of the reference laser (40) with an output of the semiconductor laser (12) and providing a difference signal as a second feedback signal to the temperature controller of the semiconductor laser in response to detected differences between the reference laser (40) and semiconductor laser (12).
Abstract:
The invention provides a measurement system to interrogate at least one birefringent optical sensor and a method to interrogate birefringent optical sensors at high speed and high resolution. The system and method detects, at least, a first and a second spectral feature that are polarization dependent, wherein the detected first and second spectral features correspond to different responses of at least one birefringent optical sensor.
Abstract:
A chip scale ultra violet laser source includes a plurality of laser elements on a substrate each including a back cavity mirror, a tapered gain medium, an outcoupler, a nonlinear crystal coupled to the outcoupler with a front facet that has a first coating that is anti-reflectivity (AR) to a fundamental wavelength of the laser element and high reflectivity (HR) to ultra violet wavelengths, and has an exit facet that has a second coating that has HR to a fundamental wavelength of the laser element and AR to the ultra violet wavelengths, a photodetector coupled to the outcoupler, a phase modulator coupled to the photodetector and coupled to the back cavity mirror, and a master laser diode on the substrate coupled to the phase modulator of each laser element. Each laser element emits an ultra violet beamlet and is frequency and phase locked to the master laser diode.