Ultrabroadband supercontinuum light expanding from ultraviolet to 6.28 μm is generated in a centimeter-long fluoride fiber pumped by a 1450 nm femtosecond laser. The spectral broadening in the fluoride fiber is caused by self-phase modulation, Raman scattering and four-wave mixing. The experimental and simulated results show that fluoride fiber is a promising candidate for generating the midinfrared supercontinuum light up to 8 μm.

A highly nonlinear composite fiber, which has a 1.5 microm chalcogenide glass core surrounded by a tellurite glass microstructure cladding, has been fabricated by the method of stack and draw. A tellurite glass capillary containing a As(2)S(3) rod was sealed with negative pressure inside. Then this capillary and other empty capillaries were stacked into a tellurite glass tube, and elongated into a cane. This cane was then inserted into another tellurite glass jacket tube and drawn into the composite microstructure fiber. The fiber has a flattened chromatic dispersion together with a zero dispersion wavelength located in the near infrared range. The propagation losses at 1.55 microm were 18.3 dB/m. The nonlinear coefficient at 1.55 microm was 9.3 m(-1)W(-1). Such a high nonlinear coefficient counteracts the high propagation losses to a large extent. A supercontinuum spectrum of 20-dB bandwidth covering 800-2400 nm was generated by this composite microstructure fiber.

We report wide and flattened supercontinuum generation in zero-dispersion-wavelength-decreasing tellurite microstructured fibers fabricated by using the tapering method. Flattened supercontinuum light expanding from 600to2800 nm can be generated when launching a 1550 nm femtosecond fiber laser into a 5-cm-long, zero-dispersion-decreasing, tellurite microstructured fiber. Our results show that short length (several centimeter) zero-dispersion-wavelength decreasing highly nonlinear fiber has a potential for generating wide and flattened supercontinuum light sources.

We report what we believe to be the first demonstration of supercontinuum generation spanning over three octaves from UV (at least approximately 350 nm) to 3.85 microm in a 2.5-cm-long fluoride fiber pumped by a 1450 nm femtosecond laser. The spectral broadening in the fluoride fiber is caused primarily by self-phase modulation. Its performance is also compared with that of a 2.5-cm-long silica fiber pumped by the same laser.

No abstract