<?php
ini_set('date.timezone', 'Europe/Lisbon');
ini_set('intl.default_locale', 'en_US');
$cal = IntlCalendar::createInstance(NULL, '@calendar=ethiopic-amete-alem');
var_dump($cal->getType());
$cal = new IntlGregorianCalendar();
var_dump($cal->getType());
The above example will output:
string(19) "ethiopic-amete-alem"
string(9) "gregorian"