K~+-Na~+Exchanged Germanate Glass Waveguide Amplifier Operating in Particular Wavelength Region
|School||Dalian University of Technology|
|Keywords||Tm3+ Germanium glasses Ion exchange waveguide amplifier Firsttelecommunication window S-band U-band Signal gains|
In fiber-optical telecommunication, the near-infrared wavelength range from800to1625nm is employed. The old first window wavelength (FWW) band (around800-850nm), whichwas earlier used for the multi-mode optical communication, has not been fully exploredbecause of the high loss and dispersion associated with the band. Recently, with the rapidexpansion of the local area network (LAN) and intercity fiber-to-home net-work, FWW bandhas come into the focus for short-range communication.1470nm belongs to S-band andlocated in the traditional wavelength-band side of Er3+. The typical1470,1800nm and800nm fluorescence of Tm3+make it attractive in infrared optical amplifier.Most optical amplifiers operating in infrared wavelength region are based on the normalStokes emission, however, for signal amplification in FWW band anti-Stokes upconversionemission plays an essential role. Up to now, rare-earth (RE) ions doped silicate,alumino-germano-silicate, and fluoride glass fibers have achieved effective signal gains in thefirst telecommunication window, which encourage us to re-examine the window again. Inaddition, with the growing request of compact and large capability communication, much ofthe research interest was centered on waveguide amplifiers owing to their potentialapplication in short-length, high-gain, and multi-channel signal amplification. In the design ofupconversion amplifiers, considering the higher sensitivity of the upconversion emission tophonon energy, to explore robust oxide glass with low phonon energy is necessary. Moreover,the upconversion emission spectra present a non-clutter fluorescence peak in infraredwavelength region in most oxide glasses, and effective amplifiers with high fidelity signalamplification can be obtained using this characteristic.Based on this consideration, Tm3+doped low phonon energy germanium glasses weredesigned and synthesized, and the optical and spectral properties of Tm3+were studied. Inaddition, the ion-exchange channek waveguide was fabricated in Tm3+/Yb3+-dopedgermanium glasses surface prepared, and its signal gain ability wass characterizaed, laying thefoundation for Tm3+, Pr3+, and Ho3+-doped germanium glasses for special-band signal amplifier. The followings are results this work achieved:1. Tm3+/Yb3+co-doped low phonon23Na2O3MgO22Al2O352GeO2-1.0wt.1.0%Tm2O3-2.0wt.%Yb2O3glasses have been designed and fabricated. Based on opticalabsorption, Judd-Ofelt parameters2,4and6have been derived，then the radiativetransition probabilities, radiative lifetimes and fluorescence branching ratios were calculated.A powerful794nm upconversion emission, which was originated from Tm3+:3H43H6transition, in Tm3+/Yb3+codoped aluminum germanate (NMAG) glasses excited at974nmlaser diode was investigated.2. K+–Na+ion-exchanged multimode channel waveguide has been fabricated in theNMAG glass substrate. The investigate results indicate that Tm3+/Yb3+codoped NMAG glasschannel waveguide is an effective device for the first window amplifier and it will arouse theresearch enthusiasm for the signal amplification in this window.3. Tm3+doped low phonon NMAG glasses have been designed and fabricated. Basedon optical absorption, Judd-Ofelt parameters2,4and6have been derived, and theradiative transition probabilities, radiative lifetimes and fluorescence branching ratios werecalculated. Efficient1.479μm and1.793μm infrared emission have been observed in Tm3+codoped aluminum germanate (NMAG) glasses excited at793nm laser diode.4. K+Na+ion-exchanged channel waveguide also have been fabricated andcharacterized in Tm3+doped NMAG glass. Experimental results and theoretical anticipationindicate that Tm3+doped NMAG glasses are potential and attractive substrates in developingS-and U-band waveguide amplifiers and eye-safe medical laser.、The present research indicates that, NMAG glass is an attractive material in fabricatingparticular wavelength band glass waveguide amplifier. Tm3+/Yb3+codoped NMAG glasschannel waveguide is an effective device for the first window amplifier. Tm3+doped NMAGglasses are potential and attractive substrates in developing S-and U-band waveguideamplifiers.