I reviewed the E-Manual for your model and there was no information listed about the size of the optical drive.
Upon doing a search on the Asus eStore using the terms internal dvd, of the several optical drives listed, each were 12.7mm.
I would recommend contacting Asus directly at verify this is the size of your optical drive. If this is the case, you may be able to order through them directly.
A search on Amazon using the terms 12.7mm ssd dvd displays multiple results that would be compatible, but I recommend verifying the dimensions before ordering.