Fault analysis: optical performance investigation of fiber connections with imperfect physical contact.
We investigated the insertion and return losses of optical fiber connections with various air-filled gaps. Such gaps might occur when a fiber connection using physical contact unexpectedly fails, resulting in imperfect physical contact. The optical performance of these fiber connections depends on wavelength and gap size. We revealed that the measured optical performance of fiber connections with an imperfect physical contact, i.e., with an air-filled gap, might deteriorate to ~18 dB for insertion loss and 9.4 dB for return loss at worst.
Chapter 3 Faults and Novel Countermeasures for Optical Fiber Connections in Fiber-ToThe-Home Networks
The number of subscribers to broadband services in Japan now exceeds 34 million, and about 20 million were using fiber-to-the-home (FTTH) services in December 2011 [1]. The number of optical fiber cables continues to increase as the number of FTTH subscribers in‐ creases; however, unexpected faults have occurred along with this increase. One such fault is damage caused by wildlife including rodents, insects, and birds [2], and another is that caused by defective optical fiber connectors [3]. It is very important to detect and investigate the causes of these faults and to apply correct countermeasures.
5.63 and 5.80 MeV levels of Ne20; de-excitation branching
Abstract The ratio Г γ /Г for the 5.63 and 5.80 MeV levels of Ne 20 has been determined to be 0.077 (±0.008) and −4 , respectively, by using the C 12 (C 12 , α)Ne 20 reaction and determining the fraction of the events in which the alpha-particle and the Ne 20 recoil are present in coincidence at the kinematically correct angles. In both cases these results in themselves are shown to imply radiative E1 transition (5.63→1.63 and 5.80→0, respectively) probabilities ⪡5 × 10 −5 Weisskopf units. When taken together with the life-time for the 5.63 MeV level measured by Evans et al . values of Г( E1 ) ≲ 5 × 10 −6 and Г α ≈ 6% of the particle estimate are obtained for this state.