$day = cal_to_jd(CAL_GREGORIAN,2,2,2010); // Julian Day count
$day_unix=jdtounix($day); // Unix time stamp
echo date('m/d/y',$day_unix);// In date format
The output is here
02/02/10
We can get unix time stamp by using gdtounix() function. Here we will use Julian Date ( Integer )as input.