GARDNER, Mass., Mar. 20 -- Precision Optics Corp. Inc. has completed a private placement valued at up to $22.9 million to institutional and private investors. Investors agreed to purchase 657,895 shares of common stock and warrants exercisable for an additional 388,157 shares of common stock; gross proceeds to the company totaled $12.5 million, with additional proceeds of up to $10.4 million possible upon exercise of the warrants.Precision Optics said these investments would allow it to acquire additional equipment and facilities, to increase production capacity for dense wavelength division multiplexer optical filters, and to develop other telecommunications products. Additional proceeds will be used for general corporate purposes.