The optical process, following grinding, that puts a highly finished, smooth and apparently amorphous surface on a Lens or a mirror.
Polishing a Fiber after it has been cleaved takes out imperfections that can result from the Cleaving process. Polishing is done by using grit abrasive paper to smooth the fiber end. There are also machine fiber polishers.
Polishing is important in assuring that fibers are free from imperfections before they are joined to a Connector or are spliced SO that there is little or no connector or Splice loss.