I had one of the original Jawbone Ups, and it was great for this. Sadly, it didn't last forever and now they're discontinued. I did a solid search about a year ago and couldn't find anything that suited - essentially a sleep tracker with a smart alarm that's not tied to a mobile phone, and ideally with the ability to wake via light as well as noise.
(I get that the Apple Watch offers options, but it never seemed sensible to use a) use quite a bulky watch to sleep with, and b) choose a watch that would ideally charge overnight, to capture sleep data.)
This one works great for me & is free.