K. Tsuji et al., Polarization-independent wavelength conversion using four-wave mixing in single-mode fibers pumped with cross-polarized high frequency pulses, IEICE TR CO, E84B(5), 2001, pp. 1190-1196
This paper describes a simple polarization-independent wavelength conversio
n method using degenerated four-wave mixing (FWM) in single-mode fibers pri
mped with cross-polarized high frequency, saw-tooth pulses from a single pr
imp source. Successful polarization-independent wavelength conversion is ex
perimentally confirmed with less than +/- 12% and +/-5.6% variation using a
gain-switched LD pumping and a mode-locked fiber laser pumping, respective
ly. We clarify that the interference effect between two orthogonal pump pul
ses must be taken into account to achieve a good polarization-insensitive o
peration. since even the small pulse edges bring about the large polarizati
on fluctuations when they are interfered. Furthermore. it is reveal that th
e shorter pump pulse broadens its own spectrum due to the self-phase modula
tion in fibers, resulting in poor FWM efficiency. Finally. possibility of h
igh-speed operation is discussed taking into account the pump pulse conditi
ons.