Atsushi Oguri

1 THz-step bandwidth upgrades in broadband Raman amplifier by adding pump laser diodes

A bandwidth-upgradeable Raman amplifier by adding laser diodes at different wavelengths was developed. We show that the total cumulative pump power can be decreased to one half for the bandwidth extension toward shorter wavelength as compared with the opposite case.

Novel Automatic Service Restoration Technique by Using Self-Reconfiguration of Network Resources for a Disaster-struck Metro-Access Network

This paper shows the concept of the elastic lambda aggregation network (EλAN) that will achieve an elastic common access infrastructure for the metro-access network. It proposes a service restoration technique that uses optical path switching and intercentral office handover for EλAN to recover from disasters. The feasibility of the proposed service restoration technique is successfully demonstrated for the first time by using a prototype testbed of a metro-access network. By applying both orthogonal frequency division multiplexing and adaptive modulation, the system automatically changes the transmission parameters (modulation level, the number of subcarriers, and symbol rate) according to the service requirements and conditions of the optical distribution network, such as the links end-to-end optical loss, in order to achieve accommodate multiple services. In the experiment, an optical network unit in a faulted system automatically reconnected within 10 s to another office 20-km away with the same throughput.

First-time Demonstration of Automatic Service Restoration by Using Inter-Central-Office OLT handover and Optical Path Switching in Metro-Access Network

The first demonstration of the service restoration technique for metro-access networks successfully shows that ONU accommodated by the disaster-stricken central office is automatically reconnected within 10 sec to another office 20-km away with the same throughput as before disaster.

Programmably repetition tunable low pedestal femtosecond pulse train generation using comb-like profiled fiber

We demonstrated programmably repetition tunability from 5 MHz to 500 MHz on low pedestal 300 fs pulse train generation through the compression of gain-switched laser diode pulse by comb-like profiled fiber with normal-dispersion Er doped fiber.

A wavelength-tunable, 10-GHz, sub-500-fs optical pulse source based on square-wave-driven LiNbO3 modulator and comb-like profiled fiber

By driving a 20-Gb/s intensity modulator with a 5-GHz square-wave, we successfully generate a 10-GHz, 15-ps optical pulse train, which is compressed to sub-500 fs in the wavelength range from 1535 nm to 1560 nm.

Repetition-rate and wavelength tunable optical short pulse source by using comb-like profiled fiber compression and supercontinuum generation

A repetition-rate and wavelength tunable optical pulse source by using comb-like profiled fiber compression and supercontinuum generation has been developed. A supercontinuum with 70 nm bandwidth is observed for 500-1000 MHz repetition rate.

Ultra short pulse generation and reshaping using highly nonlinear fibers

We experimentally investigate the generation of a low-noise ultra short pulse train from 40GHz to160GHz by using Comb-like profiled fiber (CPF) for adiabatic soliton conversion and compression. Highly nonlinear fibers allow us to reduce total length of CPF as well as to utilize Kerr effect in the fiber effectively. We demonstrate generations of 160GHz soliton train of 750fs, the compression to 500fs of 40GHz externally-modulated pulse with wideband tunability over 30nm. Then we apply the CPF pulse compression technique to achieve the programmable repetition tunability from 5 to 500 MHz in low pedestral 300fs pulse train generation.