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Working Group 4.31

Wideband-tuneable single frequency light sources

Ideal optical single frequency oscillators display a well defined carrier phase at any instant of time. Furthermore, the intensity noise is small, i. e. quantum-imited in the ideal case, in contrast to, e. g., multimode lasers which suffer from strong fluctuations due to mode competition. Wideband mode-hop-free tuning of such lasers usually requires a mechanical manipulation of resonator components, e. g. the simultaneous translation and rotation of a grating of an 'extended-cavity laser diode' (ECLD). Such kind of actuation severly limits the tuning speed and reproducibility.
We investigate several alternative approaches avoiding these disadvantages. A promising novel method employs an optical requency comb whose spectral lines are jointly shifted via so-called 'phase-serrodyning' (ATLAS method). Subsequently, the desired individual line is selectively filtered and amplified while the filter frequency follows the tuning process. We have shown that coherent Brillouin scattering in optical fibers is well suited for this purpose [1].


[1] F. Rohde, E. Benkler, and H. R. Telle, ‘High contrast, low noise selection and amplification of an individual optical frequency
comb line’
, Opt. Lett. 38, 103-105 (2013)


Dr. Erik Benkler   Phone: +49 (0)531-592 4352
    FAX: +49 (0)531-592 69 4352
    E-mail: Erik Benkler