Advanced pulsed and long-wavelength semiconductor lasers based on quantum-dot and antimonide materials
Nikkinen, Jari (2014)
2014
Teknis-luonnontieteellinen koulutusohjelma
Luonnontieteiden tiedekunta - Faculty of Natural Sciences
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Hyväksymispäivämäärä
2014-12-03
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201412051596
https://urn.fi/URN:NBN:fi:tty-201412051596
Tiivistelmä
In this thesis mid-infrared optically-pumped semiconductor disk laser (OP-SDL) emitting at 2.5 µm is developed for the very first time. Although laser diodes at this wavelength have already been reported, the motivation of this experiment is to extend the first SDL to this region. The advantage of SDLs over laser diodes is their superior beam quality with high powers, and practical potential for wavelength tuning. These properties are a great asset in many applications such as chemical sensing, biomedicine, thermal imaging and spectroscopy.
Mode-locked quantum dot edge-emitting lasers emitting at 1.2 µm and 1.3 µm are also investigated in this thesis. The purpose of these experiments is to use them as master oscillator for bismuth doped fiber amplifiers, operating at 1.2–1.3 µm. The motivation of these experiments was to build a compact system to achieve amplified short pulses with good beam quality.
Studies in this thesis were carried out experimentally. First, the SDL chip was processed and build into a laser. Then the laser output properties were measured with various instruments.
For the first time, a GaSb-based OP-SDL operating at 2.5 µm spectral range has been demonstrated. The laser operated in continuous wave as well as tunable laser. With an intra-cavity diamond heat spreader used for thermal management, 600 mW of continuous wave output power has been achieved with good beam quality. Tunable operation with 130 nm tuning range and output power up to 310 mW has been obtained, limited by the free spectral range and loss induced by the etalon.
As a conclusion, the obtained results show that the advantages of high-power disk laser technology can be extended to 2.5 µm and beyond utilizing (AlGaIn)(AsSb) semiconductor compounds. This material system was found to provide both wide band low loss mirrors and wide gain desired for tunable lasers. These characteristics allow high power and high brightness to be achieved.
The mode-locked edge-emitting quantum-dot lasers operating at 1.2 µm and 1.3 µm spectral range have been characterized in detail. For the 1.2 µm laser diode, the optimum performance resulted in 71 mW of average output power with 5.56 ps pulse width and 30.45 GHz repetition rate. Respectively, the 1.3 µm laser diode reached 20.4 mW of output power and 8.3 ps pulse width at 10.2 GHz pulse repetition rate.
For both laser diodes stable mode-locking was found to originate from ground state lasing. As a conclusion, it is shown that mode-locked edge-emitting lasers can be used as a compact ultra fast seed signal source for Bi-fiber amplifiers. Although the seed lasers themselves operated as planned, it was concluded that the Bi-amplifiers would still need further development.
Mode-locked quantum dot edge-emitting lasers emitting at 1.2 µm and 1.3 µm are also investigated in this thesis. The purpose of these experiments is to use them as master oscillator for bismuth doped fiber amplifiers, operating at 1.2–1.3 µm. The motivation of these experiments was to build a compact system to achieve amplified short pulses with good beam quality.
Studies in this thesis were carried out experimentally. First, the SDL chip was processed and build into a laser. Then the laser output properties were measured with various instruments.
For the first time, a GaSb-based OP-SDL operating at 2.5 µm spectral range has been demonstrated. The laser operated in continuous wave as well as tunable laser. With an intra-cavity diamond heat spreader used for thermal management, 600 mW of continuous wave output power has been achieved with good beam quality. Tunable operation with 130 nm tuning range and output power up to 310 mW has been obtained, limited by the free spectral range and loss induced by the etalon.
As a conclusion, the obtained results show that the advantages of high-power disk laser technology can be extended to 2.5 µm and beyond utilizing (AlGaIn)(AsSb) semiconductor compounds. This material system was found to provide both wide band low loss mirrors and wide gain desired for tunable lasers. These characteristics allow high power and high brightness to be achieved.
The mode-locked edge-emitting quantum-dot lasers operating at 1.2 µm and 1.3 µm spectral range have been characterized in detail. For the 1.2 µm laser diode, the optimum performance resulted in 71 mW of average output power with 5.56 ps pulse width and 30.45 GHz repetition rate. Respectively, the 1.3 µm laser diode reached 20.4 mW of output power and 8.3 ps pulse width at 10.2 GHz pulse repetition rate.
For both laser diodes stable mode-locking was found to originate from ground state lasing. As a conclusion, it is shown that mode-locked edge-emitting lasers can be used as a compact ultra fast seed signal source for Bi-fiber amplifiers. Although the seed lasers themselves operated as planned, it was concluded that the Bi-amplifiers would still need further development.