PHP array to postgres array

Now php can't work directly wit Postgresql array. For example, php taking postgresql array like '{"foo","bar"}'

I need simple php function to create multidimensional postgresql array from php array.

I think that experimental pg_convert() isn't optimal because it needs of extra data to form simple array string for database output, maybe I misunderstood the idea of this function.

For example, I need to convert

$from=array(  array( "par_1_1","par_1_2" ), array( "array_2_1", "array_2_2" )  );
$to='{{"par_1_1","par_1_2"},{"par_2_1","par_2_2"}}';

Can I use array_walk_recursive() to convert the deepest elements of array?