In this work, chalcogenide all-solid hybrid microstructured optical fibers (Ch-ASHMOF) using As2Se3, As2S5 and AsSe2 glasses are proposed. The polarization-maintaining properties are induced by breaking the symmetry of the rod arrangement and the core shape. The fibers have all-normal chromatic dispersion profiles which are flattened about -10 ps/km/nm over a wavelength range from 5 to 10 m and the birefringence values are up to 4.5x10-4 at 10 μm. By pumping the fiber with a 200-fs-pulse laser source at 5.3 μm, a broad supercontinuum generation from 2 to 10 μm in the mid-infrared window is experimentally demonstrated.
Fiber-based optical parametric amplification (FOPA) has been exploited for various applications due to its broad gain bandwidths and high signal gain in many spectral bands. By extending FOPA gain bandwidth towards the mid-infrared (MIR) region, more novel applications in spectroscopy, sensing, biology and so on are expected to be realized. However, highly efficient and stable FOPA performance is not easy to be obtained. It requires optical fibers with high nonlinearity, suitable control of chromatic dispersion and pump sources to satisfy the phase-matching condition which is the key for FWM process to occur. Among non-silica glasses, chalcogenide glasses have attracted great attention due to their very broad transmission window in MIR region and very high nonlinearity. For these reasons, this work is highly motivated to control and maintain the chromatic dispersion of chalcogenide optical fibers so as to achieve and maintain high-intensity and broad FOPA signal gain bandwidths in the MIR region by using an AsSe2 step-index optical fiber and a pump source near 5.0 μm. It is realized that by adding a chalcogenide buffer layer with appropriate refractive index and diameter to the conventional step-index structure, the performances of chromatic dispersion and FOPA can be improved and their fluctuation due to the change of fiber core can be greatly suppressed. As a result, a broad signal gain bandwidth from 3 to 14 μm at about 15 dB is attainable and can be maintained although the fiber core diameter drastically fluctuated from 2 to 5 μm.
Supercontinuum (SC) has been applied in many applications such as optical coherence tomography, high-precision spectroscopy and frequency metrology [1]. SC can be generated in highly nonlinear fibers by launching high intensity laser pulses into these fibers. The dynamics of SC generation (SCG) closely relates to the chromatic dispersion of the fibers [2]. In the normal dispersion regime, the spectrum broadening dynamics is mainly based on self phase modulation and optical wave breaking which are self-seeded processes. Thus, the output SC preserves its high coherence. Highly coherent and broadband mid-infrared SCG in the all-normal dispersion regime was demonstrated by pumping at 8, 10, and 12 μm [3]. However, only few laser sources are able to provide such long wavelengths. Moving the pumping laser wavelengths to around 1.5 or 2 μm will be more attractive because many commercial fiber lasers are available. In this report, we propose a novel tellurite fiber for supercontinuum generation with a pumping laser at 2 μm. The fiber is obtained by adding six solid rods around the core of a step-index fiber. Such fiber is called all-solid hybrid microstructured optical fiber (ASHMOF). The fiber possesses flattened chromatic dispersion from 2 to 4 μm. Successful fabrication of the ASHMOF was done with an in-house drawing tower. Using a laser pumping at 2 μm into the ASHMOF, highly coherent and high spectral flatness supercontinuum spanning a range from 1.4 to 3.0 μm at - 20 dB level was experimentally generated. Such broad and highly coherent SC will be valuable for applications as optical coherence tomography, ultrafast transient absorption spectroscopy, etc.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.