Presentation of project idea

1
Presentation of project idea

• Bi-doped optical fibers Photosensitivity,
  luminescence active centers, gain, and
  application
• FORC RAS, ICHPS RAS, EPFL, Univ. Milano, ESO
• Dr. Hans G. Limberger, EPFL , Lausanne

2
Agenda / content

• Possible partners
• Background
• State of the art
• Objective
• Open questions

3
Possible partners

• Institute of Chemistry of High Purity Substances,
  ICHPS RAS (Nizhny-Novgorod, Russia)
• Synthesis of high-purity glasses and realization
  of Bi-doped fibers
• Fiber optic research center, FORC RAS (Moscow,
  Russia)
• Fiber drawing, spectroscopic studies, laser
  experiments.
• Optical fiber device group, OFDG EPFL (Lausanne,
  CH)
• Study of photosensitivity and grating fabrication
• Univ. of Milano-Bicocca, Dip. di Sci. dei
  Materiali (Milano, I)
• Theoretical modeling of point defects in silica
• European Organisation for Astronomical Research
  in the Southern Hemisphere (ESO), Garching,
  Germany
• SHG realization and test

4
Background

• Why investigating fibers with fluorescence and
  gain at 1.3 mm
• Internet evolution (high definition television
  and video on demand, user oriented services) will
  ask for more and more bandwidth It is expected
  that till 2018 the bandwidth increase will be a
  factor 30100 x ? more WDM channels.
• At this moment managing light is restricted to
  C-band (erbium amplifier band), limiting the
  number of wavelength channels.

5
Background

• Why investigating fibers with fluorescence and
  gain at 1.3 mm
• ? Bi-doped fibers show broad luminescence and
  gain in the range from 1.1 1.4 mm depending on
  additional co-dopents (Al, P). Several Bi-active
  centers might be involved.
• Bi-doped active silica fibers may be the basis
  for fiber laser and amplifiers that can solve the
  problem of optical amplification in the O- and
  E-bands (1.26-1.46 um).
• Research has to be concentrated on an
  international level to get better understanding
  of conditions for luminescence, gain,
  photosensitivity and stability of involved
  centers.

6
Background

• Why fabricating all-fiber lasers and frequency
  doubling
• All-fiber lasers allow for power scaling and
  gratings improve their performance. Frequency
  doubling into the visible (yellow-orange) is of
  interest for medicine, biology, display
  technology and spectroscopy.
• High power narrowband single mode lasers are very
  attractive devices for applications such as
  yellow laser guide star, which requires a laser
  at 589 nm to excite a resonant backscattering in
  the mesospheric sodium D2 line.

7
Background

• Why investigating photosensitivity?
• Bi-doped FORC fibers show strong photosensitivity
  possibly due to Bi (results from 2008)
• Bragg grating inscription directly in Bi-doped
  fibers will increase fiber laser efficiency and
  simplify laser construction.
• Parallel luminescence studies and theoretical
  modeling are needed to identify the nature of
  Bi-PS center.

8
Background

• National funding on Bi-doped fibers in the past
• This study is funded in Russia by Academy (i.e.
  on governmental level) and Russian Foundation on
  Basic Research for the last 4 years.
• A study on photosensitivity of Bi-doped fibers
  was initiated 2 years ago in Switzerland and
  funded by Swiss national science foundation.
• Continuation of two separate national projects
  into a fused international projects with the
  integration of additional specialists would
  foster the collaboration and speed up research in
  this field.

9
State of the art

• Bi-doped glasses with IR luminescence in 2001 in
  Japan.
• Bi-doped optical fibers have been fabricated in
  2005 in Russia (FORC RAS) large variety of
  Bi-doped glasses that possess infrared
  luminescence observed. Relatively powerful and
  effective fiber lasers realized in the spectral
  range from 1140 to 1470 nm.
• Activities in Japan, Fr, UK, USA, and especially
  in China. All studies show that this fibers are
  very promising.
• Many hypothesis and theories on the nature of Bi
  luminescent center. Their identification, their
  dependence on glass host and dopant concentration
  is necessary to understand and enhance spectral
  properties and gain combined with high
  photosensitivity.

10
Objective

• Study the photosensitivity of Bi-doped fibers and
  realization of fiber Bragg gratings
• Identification of active bismuth point defects in
  silica
• Realization of all-fiber lasers (1.17 mm)
• Realization and test of yellow fiber laser

11
Open questions

• Basic versus applied research
• Enhance research on basic questions or include
  application, i.e. yellow star?

12
Thank you

• Dr. Hans G. Limberger
• Hans.limberger_at_epfl.ch
• EPFL-APL, BM4.116, station 17
• CH-1015 Lausanne, Switzerland