Design of polarity-preserved or polarity-inverted wavelength converters using cross-phase modulation in a highly nonlinear photonic crystal fiber with flat dispersion

Abstract

In this paper, we propose the design of tunable and robust wavelength converters which can perform the polarity-preserved or polarity-inverted wavelength conversion by using the cross-phase modulation (XPM) in a dispersion-flattened highly nonlinear photonic crystal fiber (DF-HNL-PCF). The newly designed wavelength converter consists of a DF-HNL-PCF and an optical band-pass filter in the simple straight-line configuration, where XPM leads to broadening the spectrum of a continuous-wave probe light and the polarity-preserved, tunable wavelength conversion is then implemented by filtering out the blue-chirped or red-chirped spectral component of a probe light. The experimental results show that the polarity-preserved wavelength converter using a DF-HNL-PCF can achieve the error-free conversion of 10 Gbit s−1 optical data signals with the maximum power penalty of less than 2.1 dB over a wavelength range of nearly 34 nm. This wavelength tunability is actually limited by an operational wavelength range of the tunable optical band-pass filter that is used to extract the wavelength-converted signal in our experiment. Moreover, the polarity-inverted wavelength conversion is observed at the XPM-based wavelength converter using a DF-HNL-PCF, for the first time. This is achieved by tuning the central wavelength of an optical band-pass filter to coincide with that of a chirped probe light.

Wavelength conversion, time demultiplexing and multicasting based on cross-phase modulation and four-wave mixing in dispersion-flattened highly nonlinear photonic crystal fiber

“…Then the injected OTDM data signal with high peak power modulates the refractive index of the fiber, which induces a phase shift of the CW probe light via XPM. Consequently, the leading edges of the converted probe light are redshifted and the trailing edges are blueshifted [27]. If the central wavelength of the followed tunable OBPF (model: Santec-OTF-950) with 1.05 nm bandwidth is detuned to the blue side with respect to the central wavelength of a probe light to appropriately select the blue sideband spectral component of the converted light, then phase modulation is converted to amplitude modulation through OBPF.…”

Modulation instability induced by cross-phase modulation in dispersion-decreasing fiber with high-order dispersion and high-order nonlinearity

“…XPM instability can occur between the two polarization components of a single beam or two beams with different wavelengths which co-propagate in a fiber. There has been a great deal of research about XPM as it can be used to realize ultra-short optical pulse phase stabilization, ultrafast pulse characterization, all-optical switching wavelength conversion, and all-optical data frequency multiplexing [5][6][7][8][9]. However, XPM affects the waveform and spectrum of each optical signal during transmission, which leads to pulse impairment and distortion, resulting in a serious limitation to the steady transmission of optical waves in fibers.…”