Generation of high repetition rate pulse trains in a fiber laser through a twincore fiber

1
Generation of high repetition rate pulse trains
in a fiber laser through a twin-core fiber
P. Peterka, P. Honzatko, J. Kanka, V. Matejec and
I. Kasik Institute of Radio Engineering and
Electronics Academy of Sciences of the Czech
republic, Prague
Photonics Prague 2002, 26-29 May 2002
2
Generation of high repetition rate pulse trains
in a fiber laser through a twin-core fiber
P. Peterka, P. Honzatko, J. Kanka, V. Matejec and
I. Kasik Institute of Radio Engineering and
Electronics Academy of Sciences of the Czech
republic, Prague

• nonlinear fiber coupler
• narrow-band comb filter
• modulational-instability fiber laser with a TCF

Photonics Prague 2002, 26-29 May 2002
3
Generation of high repetition rate pulse trains
in a fiber laser through a twin-core fiber
P. Peterka, P. Honzatko, J. Kanka, V. Matejec and
I. Kasik Institute of Radio Engineering and
Electronics Academy of Sciences of the Czech
republic, Prague

• Layout
• Modulational-instability based fiber laser
• pulse splitting in a twin-core fiber (TCF)
• parameters of the twin-core fiber filter
• fiber laser experiments
• Conclusions

Photonics Prague 2002, 26-29 May 2002
4
Modulational-instability (MI) based fiber laser
- a fiber laser producing a high-repetition rate
pulse train by the effect of MI induced in the
fibre Spectral domain MI spontaneous growth
of sidebands of a continuous wave in a nonlinear
dispersive medium Time domain Modulation
Instability (MI) breaks a CW signal or a pulse
into a modulated structure.
Photonics Prague 2002, 26-29 May 2002
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Modulational-instability (MI) based fiber laser

• MI can be induced by SPM in the anomalous
  dispersion regime, where a quasi-monochromatic
  signal spontaneously tends to generate two
  symmetric spectral sidebands

P. Franco, et al., Self-induced MI laser, Opt.
Lett., 20(19)2009, 1995.
Photonics Prague 2002, 26-29 May 2002
6
Modulational-instability (MI) based fiber laser
E. Yoshida and M. Nakazawa, Low-treshold 115-GHz
cw modulational instability erbium-doped fiber
laser, Opt. Lett 22(18)1409, 1997 P. Honzatko,
et al., Modulational-instability ?-resonator
fiber laser, Opt. Lett. 26(11)810, 2001.
Photonics Prague 2002, 26-29 May 2002
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Pulse splitting in a twin-core fibre due to
intermodal dispersion
Photonics Prague 2002, 26-29 May 2002
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Pulse splitting in a twin-core fibre due to
intermodal dispersion

• limits application of TCFs in
• all-optical switching of ultrashort (10 fs - 10
  ps) pulses
• spectral comb filters with subnanometer spacing
  of the transmission peaks
• channel power equilizers in EDFAs

Photonics Prague 2002, 26-29 May 2002
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Pulse splitting in a twin-core fibre due to
intermodal dispersion
can be utilized for the control of the pulse
repetition rate in a fiber laser.
) K. S. Chiang, et al.Experimental
demonstration of intermodal dispersion in a
two-core fibre, Optics Comm. 143(11),
pp.189-192, 1997.
Photonics Prague 2002, 26-29 May 2002
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Parameters of the TCF filter
ErTCF AD262 fibre parameters 2a(1.7 ? 0.05)
?m, d(5.95 ? 0.05) ?m, ?nmax 0.025, ??1565
9.85 ps/m
Photonics Prague 2002, 26-29 May 2002
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Spectral transmission function of the TCF
0.48-m sample of Er-doped TCF
d t and L are mutually coupled by
Photonics Prague 2002, 26-29 May 2002
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Determination of the IMD from spectral
transmission function of the TCF
l1565 nm L1.72 nm and dt9.78 ps/m
Photonics Prague 2002, 26-29 May 2002
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Fiber laser experiments
Laser setup
Photonics Prague 2002, 26-29 May 2002
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Fiber laser output periodIMD x LTCF
Time domain (Autocorrelator)
Photonics Prague 2002, 26-29 May 2002
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Fiber laser output periodIMD x LTCF
Time domain (Autocorrelator)
Spectral domain (Optical spectrum analyzer)
Photonics Prague 2002, 26-29 May 2002
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Fiber laser output periodIMD x LTCF /12
Time domain (Autocorrelator)
Spectral domain (Optical spectrum analyzer)
Photonics Prague 2002, 26-29 May 2002
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Conclusions

• We have built a PML fiber laser with repetition
  rates defined by the IMD of the TCF included in
  the cavity (as predicted by Chiang et al.)
• Highest repetition rate 206 GHz, pulse width
  2.7 ps

• Prospects for improvement
• optimization of the TCF transmission peaks
  spectral separation (by adjusting the TCF length)
  to match the maxima of the MI gain
• addition of a bandpass filter for diminishing the
  autocorrelation background of the output signal
• enhancement of the resonator frequency
  selectivity by
• lowering the cavity losses (TCF with MFD
  matching)

Photonics Prague 2002, 26-29 May 2002
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Acknowledgments
The authors especially thank G. R. Atkins of the
Australian Photonics Cooperative Research Center
for providing the Er-doped twin-core
fibre. This research has been in part supported
by the Grant Agency of the Czech Republic under
contract No.102/99/0779 and the Ministry of
Education, Youth and Sports within contract OC
265.
Photonics Prague 2002, 26-29 May 2002
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Generation of high repetition rate pulse trains
in a fiber laser through a twin-core fiber
P. Peterka, P. Honzatko, J. Kanka, V. Matejec and
I. Kasik Institute of Radio Engineering and
Electronics Academy of Sciences of the Czech
republic, Prague
Photonics Prague 2002, 26-29 May 2002