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.
Influence of Wavelength and Temperature Changes on Optical Performance of Fiber Joints With Small Gap
We have investigated the characteristics of optical fiber joints with a small gap over wide wavelength and temperature ranges. When there is a small air gap between fiber ends, the insertion loss increases between 0.0 and 0.6 dB over a wide wavelength range of 0.7-1.7 mum and a wide temperature range of -40 degC to +80 degC. The return loss varies greatly and the worst value is about 9 dB. The return loss depends on temperature with fiber end joints that employ index matching material. The value varies from more than 50 dB to a worst value of 35 dB at low temperature
Monomode optical fiber splice loss: combined effects of misalignment and spot size mismatch
Marcuse1 has shown that the fields of monomode fibers near cutoff are approximately Gaussian, and hence that splice loss can be calculated by evaluating the coupling between misaligned Gaussian beams. Based on this analysis, Nemoto and Makimoto2 derived a general equation for splice loss between nonidentical monomode fibers with combined transverse x, longitudinal z, and angular θ misalignments.2 This equation is in a particularly useful form, since the splice loss depends only on the spot size (SS) of each fiber rather than the details of the refractive-index profile.