As mentioned at https://msdn.microsoft.com/en-us/library/cc296193.aspx the connection will convert some data into PHP data types. Of particular difference to other database functions in PHP is that dates will be output as objects instead of strings.
To make the sqlsrv_fetch_{array|object}() functions return dates/times/datetimes as strings instead, specify:
'ReturnDatesAsStrings' => true
in the $connectionInfo array.
For more info about this behaviour, see https://msdn.microsoft.com/en-us/library/ee376928.aspx