Hirotaka Ono

1480-1510 nm-band Tm doped fiber amplifier (TDFA) with a high power conversion efficiency of 42 %

The highest reported power conversion efficiency of 42 % has been achieved using a high Tm/sup 3+/ concentration doped fluoride fiber amplifier with one color 1.4 /spl mu/m pumping and a double pass configuration for S-band amplification. We achieved gains exceeding 26 dB and NFs of less than 7 dB in the 1480 to 1510 nm wavelength region (30 nm bandwidth). Furthermore, an 8 /spl times/ 10 Gb/s transmission experiment clarified that there was no excess noise generated in our proposed gain-shifted GS-TDFAs.

Four-fold reduction in the speed of light at practical power levels using Brillouin scattering in a 2-m Bismuth-oxide fiber

A 2-m long Bismuth-oxide-based highly-nonlinear fiber is used to generate Brillouin-assisted slow-light. Time delays of 46-ns and a four-fold reduction in the speed of light are achieved for 180-ns pulses with a CW pump power of just ~400-mW.

120.7-Tb/s (7 SDM/180 WDM/95.8 Gb/s) MCF-ROPA un epeatered transmission of PDM-32QAM channels over 204 km

We demonstrate 120.7-Tb/s SDM/WDM unrepeatered transmission over a 204-km 7-core fiber with aggregate spectral efficiency of 53.6 b/s/Hz using a remotely pumped 7-core EDFA and Raman amplification. 17.2-Tb/s (180 × 95.8 Gb/s) PDM-32QAM signals have been transmitted at each core.

Spectrally efficient optical phase conjugation based on complementary spectral inversion for nonlinearity mitigation

We proposed complementary spectral inversion for reserved-band-less optical phase conjugation with parametric gain and broad conversion bandwidth using a novel wavelength-exchanged configuration based on highly efficient PPLN waveguides. Fiber nonlinearity mitigation for two-carrier QPSK signal was successfully demonstrated.

Mode dependent loss equaliser and impact of MDL on PDM-16QAM few-mode fibre transmission

We experimentally evaluate the relationship between mode dependent loss (MDL) and Q penalty for few-mode fibre transmission. We employ a low-MDL recirculating loop and free-space-optics type MDL equaliser and transmit 3-mode signals with PDM-16QAM modulation.

Ultra-broadband and gain-flattened EDFAs for WDM signals

This paper reviews recently developed ultra-broadband EDFAs which include an amplifier composed of a 1.55 μm-band and a 1.58 μm-band gain-flattened EDFA in a parallel configuration and an Er3+-doped tellurite fiber amplifier. Furthermore, it dcscribes improvements in the 1.55 μm-band gain-flattened fluoride-based EDFA.

Novel fiber amplifier technology

We must expand the operating wavelength range of the optical fiber amplifier if we are to achieve a large scale DWDM and CWDM optical communication system with high performance levels. In this report, we introduce the S-band amplification technique with a Tm3+-doped fluoride fiber amplifier and an Er3+-doped fiber amplifier, and a fiber Raman amplification technique with a wider application range realized by using tellurite fiber. Furthermore, we describe the use of our proposed wide optical fiber amplifiers in an 8-channel CWDM communication system.

Recent progress on few-mode fiber amplifier

One of the most important issues as regards the few-mode erbium-doped fiber amplifier (FM-EDFA) is the differential modal gain (DMG). This paper reviews various schemes for reducing the DMG. We also present results for multi-core, few-mode erbium-doped fiber amplifiers (MC-FM-EDFA).