anbu123:
is there any other alternate optocoupler available??
There are many. I just chose that one because the datasheet made it seem like a good candidate for reducing R1 to where it could be a 1W resistor (because it has a nice, high, CTR). Otherwise it was going to be a 2W or even 5W.
How about 4N35, which has a CTR of around 50% for lower IF currents (at room temperature). So, for this one, I would increase R3 to 10k, which should allow R1 to stay the same.
Caveat: (and I should have included this on my original reply) I haven't tested this, so no guarantees -- it's just meant to stir the pot, so to speak.