well..i believe,if u travel in opt u will have ur I-20 with you which is a valid F1 status...so u should not have any problem traveling outside US
but if you are on H1, then ur status changes so while coming back u need to have visa stamped for H1 status ...

but please note..your I-20 should be valid for atleast 6months..as in port of entry they will check ur I-20 ..

good luck ..