High-bandwidth measurement of femtosecond optical pulse timing based on two-dimensional transmission gating and parallel processing.

We demonstrate a high-bandwidth, precision timing measurement technique using a surface-normal two-dimensional (2D) all-optical switch and a parallel computational sensor array to achieve high-density, parallel extraction of timing information of femtosecond optical pulses. Optoelectronic parallel processing eliminates the bottleneck of conventional systems and achieves femtosecond precision and robust timing extraction using a simple on-chip algorithm. The timing fluctuation of 1- kHz, 100-fs optical pulses was extracted on a pulse-by-pulse basis.

Terabit all-optical logic based on ultrafast two-dimensional transmission gating.

Terabit all-optical complementary logic is proposed using two successive time slots to represent a unique logical status. An organic molecular thin film is used as an array of optically controlled optical switches. By utilizing the planar structure of the film and its ultrafast optical response, proof-of-principle fully optical NOT and AND logic operations were demonstrated with 400-fs interval pulses.

Discovery of novel dyes with absorption maxima at 1.1 microm.

During the process of developing organic molecules that match the wavelengths used in optical communications, we have discovered a new class of dyes, with absorption maxima at 1.1 mum, and clarified their molecular structures. The synthesis of this class of dyes was supposed to involve unexpected intramolecular tandem reactions, and the effect of alkyl substituents on such a synthesis was investigated. As a result, an effective alkyl-substituent structure for realizing a high synthetic yield and good solubility in organic solvents was found. Furthermore, thin films made of such a highly soluble dye were fabricated by solution-coating, and they exhibited a red-shifted absorption band with a maximum at approximately 1.3 mum, indicating the formation of J-like aggregates. The third-order nonlinear optical susceptibility chi(3) of these thin films at 1.3 mum, which is the wavelength used in optical communications, was measured by the Z-scan technique. The magnitude of chi(3) reaches approximately 10-7 esu. These results suggest that the solution-coated thin films of this type of dye are potential materials for optical switching at 1.3 mum and for other nonlinear optical applications.