See http://stackoverflow.com/questions/3506988/output-utf-16-a-little-stuck/3508040#3508040
This converts to UTF-8:
function unescape_utf16($string) {
/* go for possible surrogate pairs first */
$string = preg_replace_callback(
'/\\\\u(D[89ab][0-9a-f]{2})\\\\u(D[c-f][0-9a-f]{2})/i',
function ($matches) {
$d = pack("H*", $matches[1].$matches[2]);
return mb_convert_encoding($d, "UTF-8", "UTF-16BE");
}, $string);
/* now the rest */
$string = preg_replace_callback('/\\\\u([0-9a-f]{4})/i',
function ($matches) {
$d = pack("H*", $matches[1]);
return mb_convert_encoding($d, "UTF-8", "UTF-16BE");
}, $string);
return $string;
}