No abstract

No abstract

A novel tapered fiber-optic radiation sensor (TFRS) based on cerium (Ce) and terbium (Tb) co-doped YAG scintillation crystals is demonstrated for the first time. Using the CO2 laser-heated method, a Ce/Tb:YAG crystal is well embedded into silica glass cladding without any cracks. The scintillation light emitted from the YAG scintillation crystal can be directly coupled into the derived silica optical fiber by the tapered region. The loss of the derived optical fiber is 0.14 dB/cm, which is one order of magnitude lower than the 1.59 dB/cm of the YAG crystal in the TFRS. Subsequently, strong photo- and radio-luminescence of Tb3+ (5D4→7F5) ions in TFRS are achieved under ultraviolet light and high-energy ray excitation, respectively. In particular, a prominent remote radiation response of the TFRS is presented under excitation by γ-rays through fusion splicing with multimode optical fibers. The response is approximately four times larger than that of a plastic scintillation fiber (BCF-12) sensor. Furthermore, the results possess high stability as well as a good linearity between the radiation dose rate and the response intensity. The TFRS in combination with an all-silica fiber system is a promising candidate for remote radiation detection.

No abstract

By examining the spectral and amplification characteristics of Er-doped silica fiber (EDSF) and Bi/Er codoped silica fiber (BEDSF), an active doped silica fiber with broadband-and flat-gain is investigated. Results show that the bandwidth of BEDSF with a gain greater than 20 dB is approximately 50 nm. Moreover, in the entire C-band, the gain of BEDSF exceeds 26 dB with a fluctuation range of approximately 2 dB. The excellent performance may mainly come from the role of bismuth ions. Further analysis demonstrates that the emission and gain cross-sections are enhanced, the bandwidth is broadened, and the flatness is also optimized by co-doping Bi ions. The fluorescence lifetime of Er 3+ is lengthened by 1.82 ms, illustrating that there may exist energy transfer from Bi-related active centers to Er 3+ . The results indicate that the proposed BEDSF has significant potential application in optical fiber amplifiers, lasers, sensors, and so on Index Terms-Bi/Er co-doped silica fiber, broadband-and flat-gain, gain cross-sections, energy transfer * This paper has been supported by National Key Research and Development Projects (2020YFB1805800).