Inscription and characterization of waveguides written into borosilicate glass by a high-repetition-rate femtosecond laser at 800 nm

Thomas D.P. Allsop, Mykhaylo Dubov, Vladimir Mezentsev, Ian Bennion

Research output: Contribution to journalArticle


A series of waveguides was inscribed in a borosilicate glass (BK7) by an 11 MHz repetition rate femtosecond laser operating with pulse energies from 16 to 30 nJ and focused at various depths within the bulk material. The index modification was measured using a quantitative phase microscopy technique that revealed central index changes ranging from 5×10-3 to 10-2, leading to waveguides that exhibited propagation losses of 0.2 dB/cm at a wavelength of 633 nm and 0.6 dB/cm at a wavelength of 1550 nm with efficient mode matching, less than 0.2 dB, to standard optical fibers. Analysis of the experimental data shows that, for a given inscription energy, the index modification has a strong dependence on inscription scanning velocity. At higher energies, the index modification increases with increasing inscription scanning velocity with other fabrication parameters constant.
Original languageEnglish
Pages (from-to)1938-1950
Number of pages13
JournalApplied Optics
Issue number10
Publication statusPublished - 1 Apr 2010


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  • waveguides
  • borosilicate glass
  • repetition rate femtosecond laser
  • index modification
  • quantitative phase microscopy technique
  • optical fibers

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