Haruo Nakaji

Wavelength dependence of dynamic gain fluctuation in a high-speed automatic gain controlled erbium-doped fiber amplifier

We have investigated the wavelength dependence of dynamic gain fluctuation in a high-speed automatic gain controlled erbium-doped fiber amplifier. The gain overshoot of a surviving channel owing to dropping channels increases slightly with decreasing surviving channel wavelength. On the other hand, the gain undershoot of a surviving channel caused by adding channels increases drastically at wavelengths shorter than 1536 nm, while that which remains is almost constant for wavelengths longer than 1536 nm. This sudden change in the wavelength dependence of the gain undershoot is caused by the wavelength dependence of the spectral-hole burning.

Wavelength Dependent Gain Dynamics in Erbium-Doped Fiber Amplifiers for Multiwavelength Optical Networks

Wavelength dependence of gain dynamics is theoretically and experimentally studied for a high Al codoped EDF. The power transients change drastically according to the surviving channel wavelength. The time constant of power transients in the forward pumped hybrid EDFA seems to depend on front EDF characteristics. There is no noticeable difference in the gain excursion derivatives at the beginning of the transient response among the high Al codoped the high Al codoped EDFA and the hybrid EDFAs.

A temperature-insensitive erbium-doped fiber amplifier for terrestrial wavelength-division-multiplexing systems

We have evaluated a variation in the temperature dependence of an erbium-doped fiber gain spectrum by a pump wavelength in the 980-nm band for the first time. By optimizing both the pump wavelength in the 980-nm band and a temperature-sensitive gain flattening filter, the gain change of an erbium-doped fiber amplifier was successfully suppressed to 0.18 dB/sub pp/ in the temperature range between 0/spl deg/C and 65/spl deg/C and the wavelength range of 37.0 nm.

Optical coherence tomography with a multi-fiber array in sample arm

I demonstrate the fiber-type optical coherence tomography system having the tip of sample arm with multi-fiber array and imaging of the interproximal contact area of porcine molars.