Except as provided in paragraph (2) of this subsection, if an employee or Member dies after having retired under this subchapter and is survived by a widow or widower, the widow or widower is entitled to an annuity equal to 55 percent (or 50 percent if retired before
October 11, 1962) of an annuity computed under section 8339(a)–(i), (n), (p), (q), (r), and (s) as may apply with respect to the annuitant, or of such portion thereof as may have been designated for this purpose under
section 8339(j)(1) of this title, unless the right to a survivor annuity was waived under such section 8339(j)(1) or, in the case of remarriage, the employee or Member did not file an election under section 8339(j)(5)(C) or
section 8339(k)(2) of this title, as the case may be.