www.neuron.yale.edu

Is there any way in which we can insert a light electrode in the neuron code in a similar way in which we insert a current electrode or voltage electrode

Not as such, but it's a reasonable question that I have been waiting for you to ask. The real question is "how to represent the effect of photic stimulation." If your question is related to the channelrhodopsin model you are constructing, the way to represent how it is affected by photic stimulation is to change the rate constants in the course of a simulation. Further discussions about that should probably be done in that thread where the code is posted.