Shares of Finisar closed up significantly at 15.4% higher to hit $21.79 on Friday. II-VI's stock closed down nearly 19% at $38.01.
Under the deal, II-VI is buying Finisar in a "merger" agreement of cash and shares of II-VI common stock. The transaction values Finisar at $26 a share, or about $3.2 billion in equity value. Finisar shareholders would own nearly a third of the combined company.
II-VI is a maker of electronics components, developing engineered materials and opto-electronic components.
Just a year ago, Apple invested $390 million in Finisar to increase the company's research and development and production of a type of laser used in Apple's iPhone X camera.