<?php 

$currentUser = get_current_user_id();   //get  currently logged user ID  

$user = get_user_by( \'id\', $currentUser );   // Get the user Object by id

$userUrl = get_bloginfo(\'home\').\'/author/\'.$user->user_login; //Formulate the outout 

echo $userUrl; //echo the output 
?>