Ciena Posts Loss, Forecasts Flat Sales  NEW YORK (Reuters) - Telecommunications equipment maker  Ciena Corp. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=CIEN.O target=/stocks/quickinfo/fullquote"&gt;CIEN.O&lt;/A&gt; on Thursday reported a wider loss for the  fiscal third quarter due to slack demand and forecast sales in  the current quarter would be little changed from the third  quarter.