Hideki Nonen

Novel architecture of wavelength interleaving filter with Fourier transform-based MZIs

A novel wavelength interleaving filter (interleaver) has been demonstrated with Fourier transform-based Mach Zehnder interferometers (MZIs). The interleaver works as two independent 1/spl times/2 interleavers by sharing their delay lines and couplers.

Dynamic gain equalizer using proposed adjustment procedure for thermooptic phase shifters under the influence of thermal crosstalk

A dynamic gain equalizer (DGE) is required to automatically compensate for gain variations related to fiber amplifiers. This paper proposes a DGE with thermooptic (TO) phase shifters based on a single-filtered-arm interferometer. A design procedure was newly developed for the control of the TO phase shifters, which could be used to accurately control the intended attenuation profile in one adjustment. In this procedure, the Taylor series method was used as an optimization algorithm, and thermal crosstalk was taken into account. From the point of view of thermal crosstalk, the behavior of phase shifters in an array and the effect of three-dimensional (3-D) trenches formed around the phase shifters were precisely investigated. A DGE module based on 1.5%-/spl Delta/ planar lightwave circuits and the 3-D trench structure are demonstrated. The measured spectra were found to be in good agreement with arbitrarily designed profiles under open-loop control, even when there was some thermal crosstalk between phase shifters. The results indicate that the design procedure and the estimation of the thermal crosstalk are effective for accurate control of the DGE.

High resolution dynamic gain equalizer using super-high /spl Delta/ planar lightwave circuit technology

A dynamic gain equalizer has been successfully demonstrated based on super-high-/spl Delta/ PLC with 53-channel AWGs and novel trench formation technology. Low insertion loss and well-fitted spectral response were achieved over 55-nm wavelength range.

Wavelength splitters for DWDM systems

We have demonstrated chromatic dispersion free DWDM wavelength splitters by novel configuration of monolithically integrated three identical circuits, which consist of Fourier transform-based Mach Zehnder interferometers (MZI)s.

High-speed transmission copper cable for 25Gbit/s/lane

The conventional copper cable has the intra-pair skew about 10ps/m, and it makes using the copper cable for the 25Gbit/s/lane difficult. For the purpose of reducing intra-pair skew, we analyzed the generation factor of the intra-pair skew about some cables. For this analysis, we converted the S-parameters of cables into the impulse responses and the step responses of each mode. As a result, in the conventional copper cable, it became clear that the intra-pair skew was caused by the propagation time difference between differential mode and common mode, and that the reduction of the intra-par skew is difficult structurally. On the other hand, the new structure cable, “OMNIBIT®”, which has one batch extruded insulator covering two wires, does not have the propagation time difference between differential mode and common mode. It was confirmed that the new structure was hardly to increase the intra-pair skew structurally. As a result of the trial manufacturing with the new structure cable, it was confirmed that the intra-pair skew was less than or equal to 6ps/m.

Planar wave-guide interleaving filters

We have demonstrated monolithically integrated 1/spl times/4 (50-200GHz) interleaving filters, which consist of Fourier transform-based MZIs, and arrayed waveguide gratings(AWGs) with 200GHz-channel spacing suitable for interleaving WDM system.