Micro-integrated high-power narrow-linewidth external-cavity tapered diode laser at 808  nm

Abstract

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Micro-integrated high-power narrow-linewidth external-cavity tapered diode laser at 762 nm for daylight imaging

“…For the micro-integrated tapered diode laser presented here, the peak wavelength fluctuates in the range of 12 pm for CW mode operation, and peak wavelength is furthermore almost unchanged in pulsed mode operation at injected current up to the maximum of 3.0 A. For the VBG based micro-integrated tapered diode laser, the tuning rate of the wavelength versus temperature is around one order of magnitude lower, i.e., around 6 pm/K [17,22]. This means, compared with the evanescently coupled DBR laser arrays, the peak wavelength of the emission spectrum of the micro-integrated tapered diode laser is more insensitive to the injected current and operating temperature.…”

“…The peak wavelength is around 761.88 nm, and the FWHM spectral bandwidth with an injected current of 3.0 A (determined by a Gaussian fit of the main lobe of the spectrum) is around 0.20 nm. In pulsed mode operation, the changing thermal load during the pulses affects the refractive index of the gain medium and the length of the laser cavity [17]. Thus, the emission spectrum of the micro-integrated tapered diode laser varies during the pulses and leads into a broad 0.2 nm emission bandwidth in pulsed mode operation compared with a 4 pm linewidth for CW mode operation.…”

“…Compared to the MOPA approach, the external-cavity feedback technique is preferred since the additional single-mode master oscillator is not needed. In this technique, different frequency-selective elements are implemented to achieve narrow-linewidth operation of the tapered diode laser, such as bulk diffraction gratings [11], fiber Bragg gratings [14,15], and volume Bragg gratings (VBGs) [16][17][18][19][20][21].…”

“…For laser-based daylight imaging/sensing application, the laser is usually operated in pulsed mode [2][3][4]. Normally, high power narrow-linewidth tapered diode lasers and laser systems are operated in continuous wave (CW) mode [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. However, they are also well operated in pulsed mode, and in most cases, they are operated in quasi-continuous wave (QCW) condition, i.e., the duty cycle is less than a few percent and the thermal effect can be reduced significantly.…”

All-semiconductor continuous-wave volumetric ranging for spaceborne differential absorption lidar

“…Moreover, this class of lasers typically exhibits wall-plug efficiencies above 10%, even at Watt-level power outputs. [3][4][5][6][7] As a result, semiconductor lasers and power amplifiers can enable a drastic reduction in size, weight and power consumption (SWaP) of the transmitter, while allowing for highly desirable wavelength agility.…”