Hiroki Kishikawa

Proposal of all-optical wavelength-selective switching using waveguide-type Raman amplifiers and 3-dB couplers

We propose a new optical switch that can enable wavelength-selective high-speed switching for applications to photonic wavelength-division multiplexing (WDM) Internet protocol (IP) packet routing. The switch utilizes characteristics of waveguide-type Raman amplifiers and 3-dB couplers, and so it operates all-optically at a few tens of picosecond or faster speed. The operation of the switch is studied by coupled-mode theory and is verified numerically using a beam-propagation method (BPM). As a result, we found that optical waves having arbitrary wavelengths among those of incident WDM waves are amplified and switched when the amplification rate of each waveguide-type Raman amplifier is set to the proper value by pump wave injection. Moreover, the dynamic range over 30 dB was also obtained from the simulation results of the switch.

Designing of optical switches controlled by light intensity in cascaded optical couplers

Light-wave switching with optical circuits consisting of directional couplers and amplifiers is discussed. Designing of the switch structure using coupled mode theory is proposed. Using some configuration examples, we find that the light-wave switching is feasible when several conditions involving angles are maintained by properly controlling the intensity of the propagating light wave. When waveguide-type Raman amplifiers are employed as the amplifiers, wavelength-selective switching can be realized. Switching characteristics in a proposed circuit are clarified with regard to their dependence on wavelength and phase.