This paper describes experimental results of the IP traffic condition based dynamic optical path allocation network system. In the system, optical paths are dynamically allocated between congested node pairs to cope with traffic fluctuations. It seems that this experiment is the first of its kind in the world.

We considered pulse width dependence in a time-spreading Optical Code Division Multiplexing (OCDM) system using a phase encoder and decoder (127-chip, time-spreading 800 ps) by simulation. It follows that in a fully asynchronous OCDM transmission, the light source pulse width had a 20 ps degree of freedom.

In this paper, we describe a wavelength-division multiplexing visible-light communication (VLC) system using two colored light-emitting diodes (LEDs) with similar emission wavelengths. A multi-input multi-output signal-separation method using a neural network is proposed to cancel the optical cross chatter caused by the spectral overlap of LEDs. The experimental results demonstrate that signal separation using neural networks can be achieved in wavelength-multiplexed VLC systems with a bit error rate of less than 3.8×10-3 (forward error correction limit). Furthermore, the simulation results reveal that the carrier-to-noise ratio (CNR) is improved by 2dB for the successive interference canceller (SIC) compared to the zero-forcing method.

A configuration capable of wavelength routing is indispensable in constructing an optical network that has the IP-over-WDM capability. A ring network based on WDM is one of the configurations that can make wavelength routing possible. As the nodes used to construct a WDM ring network, we have the optical ADM system (OADM) and optical cross connect system (OXC). In this paper, in order to make ring network realistic, we examined a wavelength routing way using the number of possible wavelengths and the number of Node-Connections. A wavelength routing way placement on a lattice letter logically, and the all paths forward by 1 hop or 2 hops. As the parameters for determining the number of nodes and the distance of transmission, we evaluated the deterioration resulting from coherent crosstalk and OSNR. As a result of evaluation, the number of node-passes for 1 hop transmission amounts to less than 20. In addition, when we made a test bed and made evaluations, the results almost coincided with theoretical values.

We previously reported, for a coherent optical code division multiplexing (OCDM) system using fiber Bragg grating (FBG) phase en/decoders, that the signals exhibited phase shift tolerance for a difference between the light source wavelength and the Bragg wavelength of an FBG phase en/decoder when the two signals were multiplexed. However, the phase conditions of only the central wavelength among the ones forming a pulse were analyzed. For a more specific consideration, we calculated the phase of each wavelength forming the decoded pulse. In this report, the measured and calculated reflecting properties were compared and the reliability of the method was confirmed. We calculated the phase conditions of the decoded pulses and clarified the phase characteristics with regard to the phase modulation and the interference between pulses overlapped during decoding. For the realization of an asynchronous access, the FBG phase en/decoders should be designed so that the spreading time is the inverse of 2(texttransmission rate).

This paper proposes an optical access networks that guaranteed QoS in bidirections. Our scheme is the PON (Passive Optical Network) systems using OCDM (Optical Code Division Multiplexing) technology. For the bidirectional 100 Mbps guaranteed, we examined the simple decision circuit, code length (the number of chips), the number of simultaneously accesses and transmission distance. Furthermore, we reported the results that evaluated prototype of speed-down (4 Mbps, 16 chips) for the functional check of simple decision circuit.