 Shares of Ciena Corp. CIEN, 1.04 slumped 3.6 in premarket trading Thursday, after the networking systems and services company reported fiscal second-quarter profit and revenue that missed expectations, amid an increasingly challenging supply environment. Net income for the quarter to April 30 fell to 38.9 million, or 25 cents a share, from 103.1 million, or 66 cents a share, in the year-ago period. 