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Logo:iSense – Integrated Quantum Sensors
Logo Leibniz Universität Hannover
Logo:iSense – Integrated Quantum Sensors
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Ferdinand-Braun-Institut, Leibniz Institut für Höchstfrequenztechnik

One of the aims of iSense is the development of a miniaturized laser system for coldatom applications. In the context of the laser system the Ferdinand-Braun-Institut(FBH) in Berlin will micro-integrate extended cavity diode lasers (ECDLs) on aceramic carrier (microbench). ECDLs provide significantly narrower linewidth than DFB lasers and hence better suited for ultra-high precision spectroscopy. An ECDLconsists of a laser diode chip, collimation micro-optics, miniature optical isolatorsand a volume holographic Bragg grating. For frequency stabilization the laser willbe locked to the Rubidium D 2 line at 780 nm by means of transfer modulationspectroscopy ([1], [2], [3]). The miniaturized Rubidium spectroscopy cell will beprovided by the University of Hamburg (UHH). Both, the ECDL laser source andthe spectroscopy setup (includes the Rubidium cell, optics, and modulators) willbe integrated by FBH on a microbench. Additionally, the FBH will realize poweramplifiers  (PA)  for  laser  cooling  and  for  Raman  interrogation  applications,  andDFB-MOPAs near 780 nm for the realization of optical lattices. The PAs (withthe appropriate collimation micro-optics) and the DFB-MOPAs will be integratedon individual microbenches.

DFB-MOPA integrated within a 25 x 25 x 10mm 3 volume with microbench technology. The front end of the capacitivly cooled package shows the ceramic microbench with the DFB laser coupled to the power amplifier by means of a micro-optical gradient index (GRIN) lens, FBH. The lasers for iSense will be use a similar technology.



  • Development of micro-integrated narrow linewidth extended cavity diode lasers (ECDLs) for Rb spectroscopy at 780 nm. The components, like laser diodechip, optical grating, miniature optical isolators and collimation optics will be integrated on a microbench with a volume of approximately 5 x 2.5 x 1 cm3 .The laser will provide an optical power of 50 mW, a short-term (10 µ s) linewidth of 100 kHz and a frequency tuneability of ±50 GHz
  • Micro-optical integration of the spectroscopy setup with the ECDL and an optical isolator on a microbench
  • Realization of power amplifiers (PA) with up to 1 W optical power
  • Realization of DFB-MOPAs with 1 W optical power, a short term (10 µs) linewidth of less than 200 kHz


[1]  J. H. Shirley.  Modulation transfer processes in optical heterodyne saturation spectroscopy. Opt. Lett., 7:537–539, 1982. 1

[2]  Changde Xie Jing Zhang, DongWei and Kunchi Peng. Characteristics of absorp- tion and dispersion for rubidium d2 lines with the modulation transfer spectrum. OPTICS EXPRESS, Vol 11(Nr. 11):1338–1340, 2003. 1

[3]  S. A. King D. J. McCarron and S. L. Cornish. Modulation transfer spectroscopy in atomic rubidium. Measurement Science and Technology, 19(10):1–8, 2008. 1