We have developed a polymer tunable wavelength filter using cross-linked silicone as a waveguide material for wavelength division multiplexing (WDM) systems. The filter operated with a low insertion loss of 3.6-4.1 dB, a low crosstalk of < -30 dB, and a wide tuning range of 10 nm in the 20 to 80C temperature region without any changes in the spectral profile. We investigated the optical characteristics of the 32-ch WDM signals transmitted through the filter. We realized a stable filtering operation by introducing a feedback system. We also applied the filter to a WDM/SCM (subcarrier multiplexing) broadcast-and-select LAN system. We were able to realize a LAN system which operated at 6 Mbit/s and had 3200 channels by using 10-wavelength WDM signal. This suggests that our polymer tunable wavelength filter is suitable for practical use.

We have developed a new planar lightwave circuit (PLC) platform eliminating Si terraces for hybrid integrated optical modules. This PLC platform has the advantage of a lower fabrication cost than the conventional PLC platform with an Si terrace, because it does not require fabrication processes such as Si terrace forming and mechanical polishing. Using our new PLC platform structure, we fabricated a transceiver for optical access networks and an 8-channel multi-channel photoreceiver for wavelength division multiplexing (WDM) interconnection systems.

We have developed a new planar lightwave circuit (PLC) platform eliminating Si terraces for hybrid integrated optical modules. This PLC platform has the advantage of a lower fabrication cost than the conventional PLC platform with an Si terrace, because it does not require fabrication processes such as Si terrace forming and mechanical polishing. Using our new PLC platform structure, we fabricated a transceiver for optical access networks and an 8-channel multi-channel photoreceiver for wavelength division multiplexing (WDM) interconnection systems.

We have reviewed recent progress on arrayed waveguide gratings for DWDM applications. AWGs can be used to realize not only mux/demux filters with various channel spacings, but also highly integrated optical components.

We report the dispersion of two-photon absorption (TPA) coefficient, (β), in polydiacetylene (12, 8) thin film waveguides in the wavelength range less than the one-photon band-gap with a 100 femtosecond mode-locked Ti: Sapphire laser pulses. The TPA coefficient was found to be 4 cm/GW for TE polarization at 900 nm (1.38 eV) by taking into account a Gaussian intensity distribution as well as a temporal pulse shape. We observed a sharp resonance in β above the first one-photon allowed transition with a full width at half maximum (FWHM) of 90 meV.

Optical Kerr effect were applied to all-optical switching devices in the form of nonlinear waveguide directional couplers. The nonlinear waveguide directional coupler consists of a quartz thin gap between two Corning 7059 guided layers on a pyrex substrate with ion-milled grating and organic thin film as a top layer. The vacuum-deposited polydiacetylene (12, 8) film was used as an organic nonlinear material. Power-dependent switching phenomenon in this asymmetrical nonlinear directional coupler was observed by 100 fs pulse duration of mode-locked Ti: Sapphire laser.