In 10 years your investment will be worth $71,237.48. Don't forget that 48 cents.
I'm being sarcastic. I understand that we were all new to investing at some point and I don't mean to sound harsh, but based on the questions you've asked, you seem to be particularly naive about investing. If we could answer your questions, we wouldn't be sitting here on a computer posting to Yahoo. We'd be on a yacht somewhere with a bunch of supermodels.
My question for you is: why did you buy JDSU?
Don't buy it because you read something about it in last month's Money magazine and you saw that it did really well last year. Find out what the company actually does, find out the potential of that market, and look at their competitors. That will be a good start.
In my opinion, JDSU is the clear market leader in an industry with enormous growth potential. I think it (and thus the stock ultimately), will do extremely well. But guess what? Stocks go down on some days too. Maybe it will be lower next week, or next month. Maybe it will never be this low again. If you find out for sure, let me know. All I can say is that I am pretty confident in 3-7 years it will be significantly higher than it is today. That is as much "certainty" as you can get in the stock market.