Brunswick Group is handling Coherent Inc., the Santa Clara industrial laser maker, which is at the center of a bidding war.

Coherent on Jan. 19 agreed to $5.7B cash/stock merger with San Jose-based Lumentum Holdings optical and photonic products outfit,

It then received more lucrative offers and counter-offers from MKS Instruments (Andover, MA-headquartered process control systems), II-VI (Saxonburg, PA-based engineered materials, optoelectronics company) and Lumentum.

Lumentum revised its offer to $287 per-share on March 22 and gave Coherent a March 24 deadline to respond.

Brunswick has Charlie Koons, Jonathan Doorley and Rebecca Kral working the Coherent business.

MKS Instruments relies on Kekst CNC (Tom Davies and Jeremy Fielding.

II-VI uses Sard Verbinnen & Co. (George Sard, Jared Levy and David Isaacs).

Lumentum depends on Joele Frank, Wilkinson Brimmer Katcher (Eric Brielmann and Kelly Sullivan).