Poszerzenie widma impulsu laserowego poprzez zastosowanie przewężki dwustronnej na standardowym włóknie jednomodowym

• Autorzy: Stasiewicz K. A. , Młyńczak J. , Jaroszewicz L. R. , Kopczyński K.

Warianty tytułu

EN

Broadening of a pulse laser spectrum obtained by bionical taper on a standard single mode optical fiber

• Języki publikacji: PL

Abstrakty

PL

Praca przedstawia eksperymentalne wyniki poszerzenia impulsu laserowego dużej mocy w standardowych światłowodach telekomunikacyjnych. Poszerzenie uzyskano poprzez wykorzystanie technologii przewężki dwustronnej, której optymalizacja dla danego typu włókna pozwala na sterowanie tak szerokością impulsu jak i składem widmowym wychodzącej wiązki, prowadząc w konsekwencji do generacji światła białego.

EN

The papers describes the results of a laser pulse broadening in tapered standard single mode fiber. Additional description of a set - up for taper manufacturing, with a principle of its operation, based on elongation procedure of fiber-optics in a low-pressure gas burner, is also presented. A virtue of such a set-up is the possibility of different kinds of taper manufacturing, like punctual, long distance on regular or increasing distance. Tapering process allows us to change a diameter of an optical fiber what means boundary condition changes, beam is propagating in a core (made from silica) surrounded by air. There is a large refractive index step between these two media, allowing for confined pulse (with high power) in a very small area. This effect causes increasing intensity of a propagated beam and amplifies nonlinear effects, like self-phase modulation etc. The article presents the results of pulse broadening obtained in different tapers, made on a single-mode fiber for a wavelength of 1310 nm and a core diameter of about 9 žm. As a light source, the pumped laser operated at a wavelength of 532 nm, which emitted the pulses of 0.6 ns with a repetition rate of about 1 kHz, has been used. All the measured fibers with a taper have a length of about 3 m, where about 1.2 m was for the input (for easier launching) and the output (for easier connection with an optical spectrum analyzer). Experimental results show the pulse broadening in the used taper structures. The best result are obtained for a long distance taper, where the elongated part was about 50 mm (flame brush is travelling to and from along the constant length). For this taper, it can be observed more flat spectrum broadening to the longer wavelength, together with increasing average power of a laser. Theoretically the best broadening we should obtain for a taper length of about 100 mm what will be one of the next subjects of our research. Other tapers also cause broadening effects but their spectra are not so flat. Interesting example is a taper with an increasing length of elongation. We observed additional spectral pick at the wavelength of about 630 nm and 950 nm. These picks are connected with the smaller core diameter obtained in this type of tapering process (the smaller core, the larger broadening). The worst results were for a punctual taper. In this case, a diameter of a taper is very small (about several micrometers) but the losses are very high. The presented results show that biconical tapered single mode optical fiber is a good way to obtain spectral broadening (supercontinuum effect).

Słowa kluczowe

PL

poszerzenie impulsu; efekt supercontinuum; przewężka światłowodowa; laser impulsowy

EN

broadening of a pulse; supercontinuum generation; optical fiber taper; pulse laser

• Wydawca: Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
• Czasopismo: Biuletyn Wojskowej Akademii Technicznej
• Rocznik: 2007
• Tom: Vol. 56, nr 4
• Strony: 155--165
• Opis fizyczny: Bibliogr. 6 poz., wykr.

Twórcy

autor

Stasiewicz K. A.

autor

Młyńczak J.

autor

Jaroszewicz L. R.

autor

Kopczyński K.

• Wojskowa Akademia Techniczna, Wydział Nowych Technologii i Chemii, Instytut Fizyki Technicznej, 00-908 Warszawa, ul. S. Kaliskiego 2

Bibliografia

• [1] W. J. Wadsworth, A. Ortigosa-Blanch, J. C. Knight, T. A. Birks, T. P. M. Man, P. St. J. Russell, Supercontinuum generation in photonic crystal fibers and optical fiber tapers: a novel light source, J. Opt. Soc. Am. B., 19, 2002, 2148-2155.
• [2] T. A. Birks, Y. W. Li, The shape of fiber tapers, J. of Lightwave Techn., 10, 1992, 432-438.
• [3] L. R. Jaroszewicz, R. Świłło, Z. Krajewski, P. Marć, Technological set-up for TAPER type fiber-optic elements manufacturing, Optoelektronika 2003 — Oferta Nauki Polskiej dla Przemysłu, 11-12.06, Poznań, 2003, 94-96.
• [4] S. G. Leon-Saval, T. A. Birks, W. J. Wadsworth, P. Russel, Supercontinuum generation in submicron fiber waveguids, Optics Express, 12, 2004, 2864-2869.
• [5] W. J. Wadsworth, T. A. Birks, P. St. J. Russell, Supercontinuum generation in tapered fibers, Opt. Lett, 25, 2000, 1415-1417.
• [6] G. Humbert, W. J. Wadsworth, S. G. Leon-Saval, J. C. Knight, T. A. Birks, P. St. J. Russel, Supercontinuum generation system for optical coherence tomography based on tapered photonic crystal fibre, Optic Express, 14, no. 4, 2006.