All‐optical data format conversion from WDM to OTDM based on FWM

Abstract

Conversion from 2 × 10 Gb/s NRZ WDM signals to a 20‐Gb/s OTDM signal has been experimentally verified based on four‐wave mixing (FWM) in a highly nonlinear fiber (HNLF) without the need of an extra NRZ‐to‐RZ conversion step. 10‐GHz control pulses are generated by the means of super continuum (SC) generation and are therefore synchronized with each other in time. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 992–994, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21544

Optical subtraction using nonlinear mixing

“…FWM of signal and pump wavelengths creates idlers at sum and difference wavelengths which carry information from the original wavelengths. As in [6], if a number of signal and pump wavelengths are selected such that the signal wavelengths have a separation of twice that of the pump wavelengths, then FWM of each signal and pump will create idlers at a common target wavelength, as shown in Figure 1 [see Appendix]. The optical power at this target idler wavelength depends on the relative phase of each mixing product at that wavelength.…”

“…The optical wavelengths for the mixing process were selected carefully following the principle of [6], so that the mixing products occur at the same idler wavelength. The relative phase of the pump wavelengths produces optical subtraction.…”

“…a) Selection of wavelengths based on the scheme in[6] for addition b) Illustration of the subtraction process by applying a π/2 relative phase shift to one pump wavelength.…”

WDM-to-OTDM Conversion Using Supercontinuum Generation in a Highly Nonlinear Fiber

“…Recently, highly nonlinear fiber (HNLF) has attracted much attention for performing optical signal processing [13]. Therefore, another approach is to use the different nonlinearities in the HNLF such as four-wave mixing (FWM) [14], and cross-phase modulation (XPM) [15] for WDM-to-OTDM conversion. The use of nonlinear optical loop mirror (NOLM) in conjunction with a hybrid mode-locked laser (HML) [16], time-domain optical Fourier transformation (OFT) [17] for WDM-to-OTDM conversion has also been reported.…”

All-optical NRZ-to-RZ format conversion at 10 Gbit/s with 1-to-4 wavelength multicasting exploiting cross-phase modulation & four-wave-mixing in single dispersion-flattened highly nonlinear photonic crystal fiber

“…The cascaded second-harmonic generation and difference-frequency generation (cSHG/DFG) in a periodically poled lithium niobate (PPLN) waveguide [9];  FWM in a passive GaAs bulk-waveguide [10];  Either XPM or FWM in a silicon (Si) nanowire [11]  By pulse carving of an NRZ optical data stream in a hybrid III-V-on-silicon technology platform [12];  FWM [13][14][15], and optical Kerr switching & pulse pre-chirping technique [16] in nonlinear optical fiber, Mach-Zehnder delay interferometer [17], respectively;  Two-wavelength injection locked Fabry-Perot lasers [18].…”