Robertson Stephens & Co. widened its loss estimates on Redback Networks Inc. after the optical-networking company lowered its third-quarter guidance. Robertson increased its year-end loss estimate for Redback to $1.03 per share from 88 cents. For 2002, losses were adjusted to $1.04 per share from 76 cents. "These new estimates represent what we believe to be an adequately cautious assessment of the current environment's effect on Redback," Robertson said in a research note. Redback said its third-quarter revenue would be between $35 million and $40 million, due to reduced orders resulting from an already weak telecommunications market and the Sept. 11 terrorist attacks.