Ciena Corp., the Linthicum-based telecom networking equipment company, is laying off 57 employees in its distribution and product engineering departments, according to state officials. The company filed a WARN layoff notice with the Maryland Department of Labor, Licensing and Regulation that says the job cuts will take effect May 29. The state agency says it will provide outplacement services, as needed, for the affected employees.The company employs about 4,700 people.