Jingzhong Guo

Experimental research on 10 Gb/s all-optical logic gates with return-to-zero data in high nonlinear fiber

A novel scheme to realize all-optical logic gates is proposed bases on nonlinear polarization rotation (NPR) in high nonlinear fiber (HNLF). Two optical signals A and B with return-to-zero data format are injected into the HNLF together with a continuous wave C. Thanks to the optical power variation in HNLF, nonlinear birefringence will be induced between the two polarization axes. Thus it results in the nonlinear polarization rotation of the lightwave in the HNLF. Both the optical signal and continuous wave are filtered out at the output of HNLF using optical band-pass filter. By adjusting the optical power and polarization of the optical signal as well as the polarization of the polarizer with respect to the polarization of optical signal/continuous wave, multiple all-optical logic gates can be realized. Theoretical analysis of the simultaneously realization of the multiple optical logic gates based on NPR in HNLF is provided. And we demonstrated the feasibility of the scheme by realizing all optical “and”, “not”, “nxor”, “A̅ • B”, “A• B̅ ”, half-adder and half-subtracter at 10Gb/s operation.

All-optical logic NOT gate based on cross phase modulation in highly nonlinear fiber using pre-chirped pulse probe

All-optical logic NOT gate based on cross phase modulation in fiber using a negatively pre-chirped pulse probe is demonstrated with improved extinction ratio (ER) at 10 Gb/s. The output ER is improved by 3 dB using pre-chirped probe compared with the chirp free probe.

Generation of optical pulse trains at multiplied repetition frequency based on Fractional Talbot effect in fiber

The optical pulse trains at a multiplied repetition frequency is generated by Fractional Talbot effects in optical fiber. The principles of Talbot effects and Fractional Talbot effects in fiber are analyzed in this paper. The 20GHz, 40GHz and 50GHz optical pulse trains are obtained from the original pulse trains with 2.8ps width at 10GHz repetition frequency. An optical pulse at 40GHz repetition frequency is also produced by upshifting the repetition frequency of 5GHz pulse trains. The degradation of 40GHz and 50GHz pulse trains is discussed by spectrum analysis of the pulse trains and some methods are proposed to enhance the performance of the pulse trains.

40GHz millimeter wave signal generation from 10GHz-pulse trains modulation based on fractional talbot effect

An all-optical frequency-upconversion based on fractional talbot effect is experimentally reported. The 2.5-Gb/s baseband signal carried on 10GHz pulse trains is upconverted to 40GHz millimeter wave after 18.49km transmission via repetition frequency multiplication of pulse trains. The phase noise of the 40GHz is as well as −92dBc/Hz at 10kHz frequency detuning. This scheme can operate in 60GHz band by employing the appropriate fiber length based on fractional talbot effect.

40GHz optoelectronic oscillator with low frequency optical and microwave devices

A high frequency optoelectronic oscillator (OEO) using only low frequency optical and microwave devices is attractive as it provides a low cost and high quality solution at the same time. In this paper, a novel OEO scheme is reported. The proposed optoelectronic oscillator includes a 5GHz directly modulated DFB laser, an optical circulator, a 10GHz photodetector, a 10GHz RF amplifier, and a bandpass RF filter with a central frequency at 5GHz. The OEO oscillates at the 5GHz and with a continuous wave injected into the directly modulated DFB laser, higher harmonics will be generated. The harmonic order can be controlled by the frequency difference between the free running DFB laser and injection lightwave. An optical domain combined dual-loop configuration with polarization-beam splitter and a polarization-beam combiner is employed to suppress the sidemodes in each single loop. Experiment results are proposed to verify the scheme, in which 40GHz microwave is obtained.

Tunable optical frequency up-conversion in millimeter wave band

We propose a novel technique to achieve optical frequency up-conversion in millimeter wave band without any local microwave oscillator. By utilizing injection locking of Febry-Perot Laser diode, a suitable negative dispersion device and polarization interferometer, a 2.5Gb/s baseband signal is frequency up-conversion to a subcarrier modulation signal at 30.8GHz.

40 Gb/s optical demultiplexing with amplitude regeneration based data pump FOPA

40 Gb/s optical demultiplexing with amplitude regeneration is demonstrated based on data pump fiber-optical parametric amplification while a 10 GHz short pulse is used as the probe. Four 10 Gb/s output channels with at least 14 dB extinction ratio enhancement and an average 5.5 Q factor is obtained after demultiplexing.