Laser maker Coherent Inc agreed to a revised buyout offer of $6.6 billion from optical fiber firm Lumentum Holdings Inc on Wednesday, days after calling a rival bid from II-VI Inc "superior".

Coherent agreed to a $5.7 billion deal with Lumentum in January, setting off a three-way battle as bidders sought a bigger share of a market set to boom from the rising adoption of 5G networks and consumer electronics.

The Lumentum deal was followed three weeks later by a $6 billion rival bid from MKS Instruments and an another competing offer from optical components maker II-VI in February worth $6.4 billion.

Earlier this week, II-VI revised its original cash-and-stock offer to raise the cash component, prompting Coherent to call the bid "superior".

Coherent then flagged a "significantly higher" termination fee proposed by Lumentum.

On Wednesday, Coherent said the termination fee of the newly agreed deal with Lumentum remains unchanged from the original bid in January.

Under the offer, Coherent stockholders are set to receive $175 and 1.0109 Lumentum shares for each share held.