Is Giggling is the same of Laughter?

Answer 1

No they are not the same :

To giggle means to laugh in a silly, often high-pitched way, esp. with short, repeated gasps and titters, as from juvenile or ill-concealed amusement or nervous embarrassment.

whereas

To laugh means to express mirth, pleasure, derision, or nervousness with an audible, vocal expulsion of air from the lungs that can range from a loud burst of sound to a series of quiet chuckles and is usually accompanied by characteristic facial and bodily movements.