Sycamore Networks Inc., once one of the state’s hottest young companies of the telecommunications boom, plans to sell off its remaining business and wind down operations.

The Chelmsford company, founded in the late 1990s by high-profile entrepreneurs Dan Smith and Desh Deshpande, said it signed an agreement to sell its telecommunications hardware business for $18.75 million and accelerate its “pursuit of strategic alternatives” for the company’s software business.