Abstract

In the past two decades, third-order nonlinear optical properties of organic and polymeric materials have attracted considerable attention to realize all-optical signal processing devices.^1,2 Especially, the large off-resonance third-order optical nonlinearities of conjugated organic polymers with delocalized π--electron systems, such as polydiacetylenes³,⁴, are considered to be potential candidates. Although conjugated polymer is reported to have large χ⁽³⁾ and fast response time, many of them are highly intractable materials that are difficult to process to form the low-loss waveguide structures required for their application⁵. Recently, many techniques for fabricating low-loss planar waveguides in thin films of solution processible conjugated polymer have been developed⁷,⁸ besides third-order nonlinear optical polymers that exhibit low absorption have been reported⁶ Furthermore, numerous different schemes which aim is all-optical switching and all-optical logic operations have been suggested for practical devices. They are included in nonlinear prism and grating couplers and nonlinear directional couplers⁹,¹⁰, such as two-channel nonlinear directional couplers, nonlinear Mach-Zehnder interferometers, nonlinear distributed-feedback grating reflectors and adiabatic polymer-glass-waveguide all-optical switch¹¹,¹². However, though the prism coupler has attracted partially significant attention both theoretically¹³ and experimentally¹⁴, as so far we know the nonlinear prism coupling to organic polymer waveguide has only been demonstrated in single beam experiments on intense-dependent nonlinear effects¹⁵.

© 1997 Optical Society of America