Compact Tunable Light Source Based On Non-Linear Optics

Periodically poled waveguides on lithium niobate and other nonlinear materials capable of quasi-phase-matched second harmonic generation have recently achieved conversion efficiencies above 100% per watt. Combined with semiconductor diode lasers, such waveguide devices promise compact sources of blue and green light (390-490 nm) with power above 2 mW today and above 100 mW in the future. An essential prerequisite is a stable pump source, such as the external-cavity diode lasers (ECDL's) produced by New Focus, Inc. The second harmonic can be tuned by varying the input wavelength and the temperature of the nonlinear waveguide simultaneously, or designing a broad phase-matching band. In some applications such as holographic data storage and process monitoring, tunable narrowband blue and green light is highly desirable. The ECDL- doubler concept provides convenient tunability with little increase in complexity. We propose to combine periodically poled waveguide technology with compact new ECDL designs to achieve a tunable blue;green source in a 4"x4"x6ii package, which may be reduced to 1iix1"x3ii - or even smaller - by incorporating micro-optical and micro-mechanical components, The success of this program will facilitate for compact nonlinear optical sources in the 3000 - 5000 nm range.