The mechanical reliability of single mode optical fiber is determined by the presence of surface
flaws such as particles from the atmosphere during drawing or abrasion damage of the fiber surface by
physical contact with any hard surface or drawing equipment and its size distribution, which are produced
by normal fiber production methods. Proof testing is a common technique to ensure minimum strength of
the fiber and eliminate the flaws whose sizes are dependent on the stress applied during proof testing. This
paper describes the relation between the size and distribution of pre-and post-proof test flaws.