B. Luo

Photonic arbitrary waveform generation based on crossed frequency to time mapping

Microwave photonic arbitrary waveform generation based on incoherent frequency-to-time-mapping (FTTM) accompanied by intersymbol interference, so called crossed FTTM (CFTTM). The pulse shape can be defined and tuned by properly adjusting the spectrum shaper (symbol shape) and the degree of intersymbol interference. UWB-, triangular-, rectangle-, comb- and user-defined pulse shapes are experimentally obtained.

Photonic generation of phase-coded microwave signals with tunable carrier frequency

A photonic scheme to generate a phase-coded microwave signal with tunable carrier frequency based on a simple single-trip and two-pass structure is proposed. Facilitated by the fiber Bragg grating and phase modulator along the trip, both frequency doubling and signal phase coding could be achieved simultaneously. Phase-coded microwave signals at 20 and 22 GHz are experimentally generated.

Comb filter with independently tunable wavelength spacing and bandwidth using cascaded variable differential group delay elements

An all-optical comb filter with independently tunable wavelength spacing and bandwidth (BW) is proposed. Using three cascaded variable differential-group-delay elements, we demonstrate theoretically and experimentally the tunability of the comb filter with >10 dB sidelobe reduction by adjusting three elements. The wavelength spacing is determined by the first filter module, while the sidelobe suppression ratio and the BW are defined by the middle and the last one, respectively.

Self-phase-modulation based all-optical regeneration of PDM signals using a single section of highly-nonlinear fiber

We demonstrate simultaneous self-phase-modulation-based 2R regeneration of 2 x 10.65-Gb/s polarization-division-multiplexed (PDM) signals using a single section of highly nonlinear fiber (HNLF). Mitigation of inter-channel nonlinearities is achieved through a bidirectional configuration, rejecting of backward Stimulated Brillouin Scattering noise is obtained by signal re-polarizing before the offset filter and putting the center wavelength of filter at the short wavelength side of the signal. The power penalty improvement up to 2.0 dB for two PDM signals at 10(-9) BER is achieved.

Simultaneous NRZ-to-RZ format conversion and one-to-six error-free channel multicasting using a single pump in a highly nonlinear fiber

We demonstrate simultaneous 10-Gb/s NRZ-to-RZ format conversion and multicasting from one to many data channels in a highly nonlinear fiber (HNLF) with only a single pump. Functionalities are achieved based on various nonlinear effects, such as four-wave-mixing (FWM), cross-gain-modulation (XGM) and cross-phase-modulation (XPM) between the pump channel and the NRZ data channel. Up to five and six converted data channels are error-free (10(-9) BER) as the wavelength spacing between the pump and the NRZ signal is set to 0.4-nm and 0.8-nm, respectively.

Simultaneous all-optical RZ-to-NRZ format conversion for two tributaries in PDM signal using a single section of highly nonlinear fiber

Simultaneous all-optical RZ-OOK to NRZ-OOK format conversion for two tributaries in PDM signal is demonstrated utilizing a single section of highly nonlinear fiber through polarization nonlinear loop mirror configuration. Less than 1-dB power penalty is achieved in a 2 × 12.5-Gb/s PDM system, and only 1.4-dB SNR penalty is obtained in a 2 × 40-Gb/s PDM system.

All-Optical Signal Regeneration in Polarization-Division-Multiplexing Systems

Schemes of all-optical regeneration in polarization-division-multiplexing (PDM) systems are proposed and demonstrated with 2 × 10-Gb/s return-to-zero on-off-keying (RZ-OOK) transmission. Regeneration is achieved based on self-phase-modulation (SPM) effect and detuned filtering in highly nonlinear fiber (HNLF) with a polarization-diversified loop configuration. Furthermore, the ability of mitigating polarization-mode-dispersion (PMD) effects in PDM systems is evaluated. More than 3.7-dB eye-diagram-based signal-to-noise-ratio (SNR) improvement is achieved in the presence of 6.3-ps PMD as the pulsewidth of the PDM signal is about 18 ps.

Determination of wavelength dependence of the reflectivity at AR coated diode facets

Wavelength dependence of the reflectivity at an antireflection (AR) coated diode facet has been determined by comparing the spontaneous emission spectra obtained under the same bias condition before and after this facet is AR coated. Reliable measurements can be achieved by proper choice of the bias current.<<ETX>>

A Tunable Microwave Photonic Filter With a Complex Coefficient Based on Polarization Modulation

A tunable microwave photonic filter with a complex coefficient based on polarization modulation and a single laser source is proposed and demonstrated. Two out-of-phase microwave signals with orthogonal polarization states are generated using a polarization modulator and then combined into one special polarization state to introduce certain phase shifts after filtering out one sideband. The tunability of the filter with the complex coefficient is achieved by adjusting the phase shifts between two taps. In addition, the frequency response of the proposed filter from 10 to 11 GHz with FSR of 400 MHz is measured.

A Photonic Comb Filter With Independently and Digitally Tunable Bandwidth and Frequency Spacing

A photonic comb filter with digitally tunable bandwidth and frequency spacing is proposed. Using cascaded differential-group-delay (DGD) element and polarization switch based filters, we demonstrate independent tunability of both parameters with >; 12-dB first-sidelobe reduction for a 6-bit configuration. Limitations of such an approach are also discussed.