Abstract

High-repetition rate femtosecond lasers are shown to drive heat accumulation processes that are attractive for rapid writing of low-loss optical waveguides in transparent glasses. A novel femtosecond fiber laser system (IMRA America, FCPA µJewel) providing variable repetition rate between 0.1 and 5 MHz was used to study the relationship between heat accumulation and resulting waveguide properties in fused silica and various borosilicate glasses. Increasing repetition rate was seen to increase the waveguide diameter and decrease the waveguide loss, with waveguides written with 1-MHz repetition rate yielding ~0.2-dB/cm propagation loss in Schott AF45 glass. A finite-difference thermal diffusion model accurately tracks the waveguide diameter as cumulative heating expands the modification zone above 200-kHz repetition rate.

© 2005 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |

  1. P.R. Herman, R.S Marjoribanks, and A. Oettl, �??Burst-ultrafast laser machining method,�?? US Patent (6,552,301 B2)
  2. C.B. Schaffer, J.F. Garcia, and E. Mazur, �??Bulk heating of transparent materials using a high-repetition rate femtosecond laser,�?? Appl. Phys. A 76, 351-354 (2003).
    [CrossRef]
  3. K. Minoshima, A.W. Kowalevicz, I. Hartl, E.P. Ippen, and J.G. Fujimoto, �??Photonic device fabrication in glass by use of nonlinear materials processing with a femtosecond laser oscillator,�?? Opt. Lett. 26, 1516-1518 (2001).
    [CrossRef]
  4. S. Nolte, M. Will, J. Burghoff, and A. Tünnermann, �??Ultrafast laser processing: new options for three-dimensional photonic structures,�?? J. Modern Optics. 51, 2533-2542 (2004)
    [CrossRef]
  5. R. Osellame, N. Chiodo, V. Maselli, A. Yin, M. Zavelani-Rossi, G. Cerullo, P. Laporta, L. Aiello, S. De Nicola, P. Ferraro, A. Finizio, and G. Pierattini, �??Optical properties of waveguides written by a 26 MHz stretched cavity Ti:sapphire femtosecond oscillator,�?? Opt. Express 13, 612-620 (2005), <a href= "http://www.opticsexpress.org/abstract.cfm?URI=OPEX-13-2-612">http://www.opticsexpress.org/abstract.cfm?URI=OPEX-13-2-612</a>.
    [CrossRef] [PubMed]
  6. R. Osellame, N. Chiodo, G. Della Valle, S. Taccheo, R. Ramponi, G. Cerullo, A. Killi, U. Morgner, M. Lederer, and D. Kopf, �??Optical waveguide writing with a diode-pumped femtosecond oscillator,�?? Opt. Lett. 29, 1900-1902 (2004).
    [CrossRef] [PubMed]
  7. K. Miura, J. Qiu, H. Inouye, T. Mitsuyu, and K. Hirao, �??Photowritten optical waveguides in various glasses with ultrashort pulse laser,�?? Appl. Phys. Lett. 71, 3329-3331 (1997).
    [CrossRef]
  8. Y. Sikorski, A.A. Said, P. Bado, R. Maynard, C. Florea, and K. Winick, �??Optical waveguide amplifier in Nd-doped glass written with near-IR femtosecond laser pulses,�?? Electron. Lett. 36, 226-227 (2000).
    [CrossRef]
  9. K.M. Davis, K. Miura, N. Sugimoto, and K. Hirao, �??Writing waveguides in glass with a femtosecond laser, Opt. Lett. 21, 1729-1731 (1996).
    [CrossRef] [PubMed]
  10. A.M. Streltsov and N.F. Borrelli, �??Study of femtosecond-laser-written waveguides in glasses,�?? J. Opt. Soc. Am. B 19, 2496-2504 (2002)
    [CrossRef]
  11. Y. Jaluria and K.E. Torrance, Computational Heat Transfer (Taylor & Francis, New York, 2003).
  12. Thermal data for AF45 glass provided by M. deCastro, Schott glass.
  13. A.F. Van Zee and C.L. Babcock, �??A method for the measurement of thermal diffusivity of molten glass,�?? J. Am. Ceram. Soc., 34, 244-250 (1951).
    [CrossRef]
  14. L. Shah, A. Y. Arai, S. M. Eaton, and P. R. Herman, "Waveguide writing in fused silica with a femtosecond fiber laser at 522 nm and 1 MHz repetition rate," Opt. Express 13, 1999-2006 (2005), <a href= "http://www.opticsexpress.org/abstract.cfm?URI=OPEX-13-6-1999">http://www.opticsexpress.org/abstract.cfm?URI=OPEX-13-6-1999</a>.
    [CrossRef] [PubMed]
  15. Y. Okamura, S. Yoshinaka, and S. Yamamoto, �??Measuring mode propagation losses of integrated optical waveguides: a simple method,�?? Appl. Opt. 22, 3892-3894 (1983).
    [CrossRef] [PubMed]

Appl. Opt.

Appl. Phys. A

C.B. Schaffer, J.F. Garcia, and E. Mazur, �??Bulk heating of transparent materials using a high-repetition rate femtosecond laser,�?? Appl. Phys. A 76, 351-354 (2003).
[CrossRef]

Appl. Phys. Lett.

K. Miura, J. Qiu, H. Inouye, T. Mitsuyu, and K. Hirao, �??Photowritten optical waveguides in various glasses with ultrashort pulse laser,�?? Appl. Phys. Lett. 71, 3329-3331 (1997).
[CrossRef]

Electron. Lett.

Y. Sikorski, A.A. Said, P. Bado, R. Maynard, C. Florea, and K. Winick, �??Optical waveguide amplifier in Nd-doped glass written with near-IR femtosecond laser pulses,�?? Electron. Lett. 36, 226-227 (2000).
[CrossRef]

J. Am. Ceram. Soc.

A.F. Van Zee and C.L. Babcock, �??A method for the measurement of thermal diffusivity of molten glass,�?? J. Am. Ceram. Soc., 34, 244-250 (1951).
[CrossRef]

J. Modern Optics

S. Nolte, M. Will, J. Burghoff, and A. Tünnermann, �??Ultrafast laser processing: new options for three-dimensional photonic structures,�?? J. Modern Optics. 51, 2533-2542 (2004)
[CrossRef]

J. Opt. Soc. Am. B

Opt. Express

Opt. Lett.

Other

Y. Jaluria and K.E. Torrance, Computational Heat Transfer (Taylor & Francis, New York, 2003).

Thermal data for AF45 glass provided by M. deCastro, Schott glass.

P.R. Herman, R.S Marjoribanks, and A. Oettl, �??Burst-ultrafast laser machining method,�?? US Patent (6,552,301 B2)

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (5)

Fig. 1.
Fig. 1.

Ultrafast laser beam delivery system for transverse waveguide writing

Fig. 2.
Fig. 2.

Optical microscope images showing heat affected zones created in AF45 borosilicate glass with 450-nJ pulse energy from a 1045-nm femtosecond laser. Total pulse (top) and fluence accumulation (bottom) is shown for each column and the laser repetition rate is indicated for each row. Laser direction is normal to page.

Fig. 3.
Fig. 3.

Finite-difference model of glass temperature versus exposure, at a radial position of 2 µm from the center of the laser beam.

Fig. 4.
Fig. 4.

Melt radius versus net fluence: numerical simulation (solid line) assuming 40% absorption and observed waveguide diameter (solid circle).

Fig. 5.
Fig. 5.

Left to right: cross sectional (a) and transverse (b) microscope images, and 1550-nm mode profile (c) of waveguide written in AF45 at 1 MHz, 520 nJ, 0.65-NA and 15 mm/s. The red arrows indicate the direction of the femtosecond laser.

Tables (1)

Tables Icon

Table 1. Glass properties Schott and Corning glasses [12]

Equations (2)

Equations on this page are rendered with MathJax. Learn more.

E ( r ) = E 0 exp ( r 2 w 0 2 )
r ( r 2 T r ) = r 2 D T t

Metrics