Precious metal refiner Chugai Mining Co. said Monday it has agreed to purchase a 21 percent stake in U.S. optic technology venture company Katsina Optics Inc. for $7 million in an effort to meet the growing demand for swift, inexpensive fiber-optic network-related services.

Chugai Mining said it will also extend loans worth $3 million to the California-based Katsina Optics.

If Chugai Mining requests it, the loans could be repaid in the form of Katsina Optics' stock, which would give the Japanese company a 30 percent stake in the U.S. firm, Chugai Mining said.

Chugai Mining said the company plans to sign an agreement with Katsina Optics at the end of next month.

Under the agreement, Katsina Optics will give Chugai Mining's subsidiary, Spider Systems of Japan Inc., exclusive rights to sell all Katsina Optics products worldwide, Chugai Mining said.

Katsina Optics is a wholly owned subsidiary of Citron Technology Group Inc. of the United States.