R.R.
I agree with the others who say that she is too young, and the fact she sleeps through the night so well is just great! Whatever she is doing now will likely change again. She may be going through a growing spurt or a touchpoint. I understand the desire to not have to spend a lot of time putting her to sleep once you're back to work. I've read a lot of the different sleep books and my thought is that you can start developing some rituals and habits that will help that to happen later when she's a little older (which could be only a few weeks from now, or even sooner, you never know). For example, having a bedtime ritual (bath, reading), rubbing her belly in the crib when she wakes instead of picking her up right away, giving her a favorite stuffed toy or blanket to hold. But for now if it doesn't take, don't worry too much, she is still young. Also, assuming you're using a nanny or day care when you return to work, tell them what's going on with her and what you're trying to accomplish (be clear that you're not using CIO). She will likely respond better to their efforts and that will help things along. I firmly disagree with CIO, especially for such a young one. There are a lot of sleep books out there with different stances, and it comes down to what works for you and for your little one. The most rational, unbiased source I've read so far isn't even a sleep book. It's a short chapter in a developmental book called "Touchpoints" by Brazelton. It explains the whole sleep issue succinctly. Keep in mind that this will pass, and the fact that she's sleeping through the night is a major accomplishment!