Yongheng Dai

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We demonstrate a novel fiber-based in-line DPSK demodulator using an in-fiber Mach-Zehnder interferometer (MZI). The device is fabricated by mismatch splicing of a photonic crystal fiber (PCF) with standard single mode fibers. The spectral characteristics at different PCF lengths are analyzed. The envelope of the interference fringes show a period that is(More)
We report a demodulator for DPSK signals at variable bit rates based on cascaded four-wave mixing (FWM). The demodulation utilizes two FWM processes in a photonic crystal fiber (PCF) with in-between dispersion in a chirped fiber Bragg grating (CFBG). The first FWM generates a wavelength-tunable idler carrying phase information of the signal. A tunable(More)
We propose a scheme to generate ultrawideband (UWB) monocycle pulses using delayed interference of a π/2 phase-shift keying (PSK) signal. The PSK signal is generated with an optical phase modulator. A fiber-based delay interferometer is used to provide the delay together with a ±π/2 phase shift between the signals in its two arms before the interference.(More)
We demonstrate a unique solution to use a one-pulse control to achieve simultaneous two-channel all-optical demultiplexing that usually requires a two-pulse control or a two-step operation based on the conventional approaches. By applying a dispersion asymmetric nonlinear optical loop mirror (DA-NOLM) to introduce cross phase modulation (XPM) in both the(More)
We demonstrate reconfigurable photonic ultrawideband (UWB) pulse generation by injecting a phase-modulated optical wave into a semiconductor laser. By adjusting the injection power level and phase modulation depth, the photonic UWB generator is capable of generating either a single-optical-carrier monocycle or power-efficient UWB pulses. A UWB pulse with(More)
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