 Shares of Coherent Inc. rose 1.8 in premarket trading Wednesday, after the laser technology company announced an amended buyout agreement with Lumentum Holdings Inc. , in which the value of the cash-and-stock deal increases to 6.6 billion from about 5.7 billion. The revised terms comes after II-VI Inc.s unsolicited bid, valued at about 6.4 billion, or 260 a share, was deemed by Coherent earlier this week to be superior to the original deal with Lumentum. 