Browsing by Subject "Ytterbium-doped fiber lasers"
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Item Open Access 1018 nm Yb-doped high-power fiber laser pumped by broadband pump sources around 915 nm with output power above 100 W(OSA - The Optical Society, 2017) Midilli, Y.; Efunbajo, O. B.; Şimşek, B.; Ortaç, B.We demonstrate a 1018 nm ytterbium-doped all-fiber laser pumped by tunable pump sources operating in the broad absorption spectrum around 915 nm. In the experiment, two different pump diodes were tested to pump over a wide spectrum ranging from 904 to 924 nm by altering the cooling temperature of the pump diodes. Across this so-called pump wavelength regime having a 20 nm wavelength span, the amplified stimulated emission (ASE) suppression of the resulting laser was generally around 35 dB, showing good suppression ratio. Comparisons to the conventional 976 nm-pumped 1018 nm ytterbium-doped fiber laser were also addressed in this study. Finally, we have tested this system for high power experimentation and obtained 67% maximum optical-to-optical efficiency at an approximately 110 W output power level. To the best of our knowledge, this is the first 1018 nm ytterbium-doped all-fiber laser pumped by tunable pump sources around 915 nm reported in detail.Item Open Access Development of a rapid-scan fiber-integrated terahertz spectrometer(Springer New York LLC, 2014) Keskin, H.; Altan, H.; Yavas, S.; Ilday, F. O.; Eken, K.; Sahin, A. B.Scientists in terahertz (THz) wave technologies have benefited from the recent developments in ultrafast laser technologies and RF technologies and applied these new gained techniques into characterizing a wide variety of phenomena. Undoubtedly, the most successful of these applications has been in the development of time-domain terahertz spectroscopic and imaging systems which has been utilized in the characterization of dielectrics and semiconductors. This pulsed technique has allowed users to characterize dynamical behavior inside materials under illumination with picosecond resolution. Typically pump/probe or similar dynamical measurements require the use of amplified pulses derived from free-space solid state lasers in the μJ-mJ range and since interferometric techniques are typically used in pulsed measurements the measurement time of a THz spectrum can last at least tens of minutes. Better systems can be realized based on fiber laser technologies. Here we discuss the advantages of a THz spectrometer driven by an ultrafast Ytterbium doped fiber laser whose repetition rate can be tuned rapidly allowing for rapid dynamical measurements. The efficient gain medium, robust operation and compact design of the system opens up the possibility of exploring rapid detection of various materials as well as studying dynamical behavior using the high brightness source.Item Open Access Generation of soliton molecules with independently evolving phase in a mode-locked fiber laser(Optical Society of America, 2010) Ortaç, Bülend; Zaviyalov, A.; Nielsen, C.K.; Egorov, O.; Iliew, R.; Limpert, J.; Lederer, F.; Tünnermann, A.We report the experimental generation of two-soliton molecules in an ytterbium-doped fiber laser. These molecules exhibit an independently evolving phase and are characterized by a regular spectral modulation pattern with a modulation depth of 80%. © 2010 Optical Society of America.Item Open Access Observation of soliton molecules with independently evolving phase in a mode-locked fiber laser(2010) Ortaç, B.; Zaviyalov, A.; Nielsen, C.K.; Egorov O.; Iliew, R.; Limpert J.; Lederer F.; Tünnermann, A.We report the experimental generation of two-soliton molecules in an all-polarization-maintaining ytterbium-doped fiber laser operating in the normal dispersion regime. These molecules exhibit an independently evolving phase and are characterized by a regular spectral modulation pattern with a modulation depth of 80% measured as an averaged value. Moreover, the numerical modeling confirms that the limited modulation depth of the spectrum is caused by the evolution of the phase difference between the pulses. © 2010 Optical Society of America.Item Open Access Repetition rate tuning of an ultrafast ytterbium doped fiber laser for terahertz time-domain spectroscopy(IEEE, 2013) Keskin H.; Altan H.; Yavaş, Seydi; İlday, F. Ömer; Yagci, M.E.; Aydin O.; Eken, K.; Sahin, B.Repetition rate tuning enables the fast acquisition of THz pulse profiles [1]. By using this method we demonstrate a compact and broadband terahertz time domain spectroscopy system (THz TDS) driven by ytterbium doped fiber laser source. The importance of this method is realized in that Yb:doped fiber lasers can be amplified to sub-millijoule pulse strengths more easily than other types of fiber lasers [2]. Hence, it has the potential to be used in excite-THz probe experiments. Furthermore, the repetition rate-tuning adds flexibility in the excite-probe techniques. These attributes as well as THz generation and detection are investigated with the laser that was developed. © 2013 IEEE.