Abstract

The photorefractive effect in electro-optic crystals has been extensively studied for many applications. These include real-time holography, optical data storage, and phase-conjugate wavefront generation. Recently, interest has grown in the use of two-wave mixing to produce nonreciprocal energy transfer between two beams. Both theoretical and experimental evidence indicate that the energy transfer occurs without any phase crosstalk. This unique characteristic allows coherent combination of light from two (or more) injection locked lasers whose relative phases cannot be controlled. We describe and demonstrate he use of two-wave mixing in photorefractive BaTiO₃ to coherently combine the outputs from two locked, single mode diode lasers operating near 830 nm. Neglecting Fresnel and absorption loses, transfer of over 70% of the power in one beam to the other has been observed using this method. In addition to the coherent summation of light from two single element laser diodes, the results of experiments on combining the output of an injection locked multi-element laser diode array with light from a single element laser diode will be presented.

© 1988 Optical Society of America