the unit of the emitted power

I am modelling an LED using comsol and I want to get the LED emitted optical power . Then I used the "semi.ot1.dP_dE" which name is the emitted power per unit volume and energy and the unit of the "semi.ot1.dP_dE" is "1/(m^3*s)" . But the unit of the power is "W".
The result "2.8E16" I have got is far from the accurate optical power value . i think the "semi.ot1.dP_dE" is not the optical power. So, which one is the optical power?
anyone can help me? thanks a lot!