In regards to X-mas lights and rope lights they can work, but they might not be optimal in all cases, especially in larger coops...
The threshold for photo-stimulation in chickens is about 0.15 foot candles, but maximum egg production is not achieved until about 0.5 - 1.0 foot candles or greater...
1.0 foot candle is about 10.764 LUX, so you should aim to achieve about 11 LUX in your coop if you want to assure yourself of maximum light stimulation levels...
If you have a smart phone you can download a LUX meter app (lots of free ones, at least for Android) they are not all that accurate but they give you a clue, I would aim for 15+ LUX if you are using a cell phone app, just to be sure and account for the fact they are not that accurate... Hold the phone horizontal at the chickens head height around the coop to take measurements around the coop...
Also be aware that the human eye is horrible at gauging light intensity as it dynamically adjust to compensate for the available light..,
Right now as I type this its about 4:30PM on an overcast day with the sun obviously on the way down... In my house in rooms with open windows and no artificial light my phone is only showing about 1-5 LUX depending on the room, enough to see and do stuff but not enough to optimally stimulate chickens or comfortably read a book... I held my phone horizontal next to some windows in the house and the LUX is still only 50-100 give or take... On the other hand as soon as I step outside it jumps to 3500+.... It's amazing how it jumps and it's amazing how inferior artificial lights are, especially as the distance increases, that whole square inverse law. comes into play very fast with artificial lights...