It's not really a 'barcode' as such. It's just a piece of text that can be 'read' or scanned by machine. The <<<< symbols just seperate out the text so the machine reading the passport knows where the data starts and ends.
The top line contains your nationality, surname and then first names eg: P<GBRSMITH<<PAUL<FRED<<<<<<<<<<<<<<<<<
The second line contains your passport number, date of birth, and passport expiry date (with a few odd characters as well).
Nothing sinister
I assume the new biometric coded passports that the USA are insisting on will contain some sort os barcode or even a chip to hold all the extra data.