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Gerbrunn, Germany

Krzempek K.,Wroclaw University of Technology | Lewicki R.,Rice University | Nahle L.,Nanoplus GmbH | Fischer M.,Nanoplus GmbH | And 5 more authors.
Applied Physics B: Lasers and Optics | Year: 2012

The development of a continuous wave (CW), thermoelectrically cooled (TEC), distributed feedback (DFB) laser diode based spectroscopic trace-gas sensor for ultrasensitive and selective ethane (C 2H 6) concentration measurements is reported. The sensor platform used tunable diode laser absorption spectroscopy (TDLAS) based on a 2f wavelength modulation (WM) detection technique. TDLAS was performed with a 100 m optical path length astigmatic Herriott cell. For an interference free C 2H 6 absorption line located at 2976.8 cm -1 a 1σ minimum detection limit of 240 pptv (part per trillion by volume) with a 1 second lockin amplifier time constant was achieved. In addition, reliable and long-term sensor performance was obtained when operating the sensor in an absorption line locked mode. © Springer-Verlag 2011. Source

Fuchs P.,Nanoplus GmbH | Friedl J.,University of Wurzburg | Hofling S.,University of Wurzburg | Koeth J.,Nanoplus GmbH | And 3 more authors.
Optics Express | Year: 2012

We report the fabrication of single mode quantum cascade lasers using a shallow-etched distributed Bragg reflector as frequency selective element. Quasi-continuous single mode tuning over 15 cm-1 at room temperature and 25 cm-1 via temperature tuning at Peltier temperatures is demonstrated. The behavior of both electro-optic and spectral characteristics under variation of the segment currents is analyzed, showing a maximum peak output power at room temperature of 600 mW. Thermal crosstalk between the laser segments is investigated. The spectral resolution of a gas absorption experiment is determined to be better than 0.0078 cm-1. © 2012 Optical Society of America. Source

Fuchs P.,Nanoplus GmbH | Semmel J.,University of Wurzburg | Friedl J.,University of Wurzburg | Hofling S.,University of Wurzburg | And 3 more authors.
Applied Physics Letters | Year: 2011

We report on the growth, processing, and characterization of distributed feedback quantum cascade lasers emitting in single mode at 13.8 μm. Lasers were grown in the indium phosphide material system with a bound-to-continuum active region and processed as double channel ridges with metalized top grating. Electro-optic characteristics as well as current and temperature tuning are investigated. Maximum single mode peak powers exceeding 800 mW at room temperature and intrapulse-tuning covering 3 cm-1 for a gas absorption experiment are demonstrated. Furthermore data on the far field are presented showing a slow-axis divergence angle of 28.3° (full width at half maximum). © 2011 American Institute of Physics. Source

Weih R.,University of Wurzburg | Nahle L.,Nanoplus GmbH | Hofling S.,University of Wurzburg | Koeth J.,Nanoplus GmbH | Kamp M.,University of Wurzburg
Applied Physics Letters | Year: 2014

Single mode distributed feedback (DFB) interband cascade lasers were realized by placing metal gratings laterally to dry etched ridges. A discrete tuning range of 104 nm could be realized on the same gain material by a variation of the grating period. At room temperature, a 2.4 mm long and 9.8 μm wide ridge with as-cleaved facets emitted more than 6 mW of single mode output power in continuous-wave (cw) mode at a wavelength around 3.8 μm. With typical temperature- and current-tuning rates of 0.31nm/°C and 0.065 nm/mA, respectively, a total tuning bandwidth of more than 10 nm could be covered with a single device. © 2014 AIP Publishing LLC. Source

Zeller W.,Nanoplus GmbH | Kamp M.,University of Wurzburg | Koeth J.,Nanoplus GmbH | Worschech L.,University of Wurzburg
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

Distributed feedback (DFB) laser diodes nowadays provide stable single mode emission for many different applications covering a wide wavelength range. The available output power is usually limited because of catastrophical optical mirror damage (COD) caused by the small facet area. For some applications such as trace gas detection output powers of several ten milliwatts are sufficiently high, other applications like distance measurement or sensing in harsh environments however require much higher output power levels. We present a process combining optimizations of the layer structure with a new lateral design of the ridge waveguide which is fully compatible with standard coating and passivation processes. By implementing a large optical cavity with the active layer positioned not in the middle of the waveguide layers but very close to the upper edge, the lasers' farfield angles can be drastically reduced. Furthermore, the travelling light mode can be pushed down into the large optical cavity by continuously decreasing the ridge waveguide width towards both laser facets. The light mode then spreads over a much larger area, thus reducing the surface power density which leads to significantly higher COD thresholds. Laterally coupled DFB lasers based on this concept emitting at wavelengths around 976 nm yield hitherto unachievable COD thresholds of 1.6 W under pulsed operation. The high mode stability during the 50 ns pulses means such lasers are ideally suited for high precision distance measurement or similar tasks. © 2010 Copyright SPIE - The International Society for Optical Engineering. Source

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