All-optical differentiator and high-speed pulse generation based on cross-polarization modulation in a semiconductor optical amplifier

Institute of Optical Information and Key Laboratory of Luminescence and Optical Information of Ministry of Education, Beijing Jiaotong University, Beijing, China.
Optics Letters (Impact Factor: 3.29). 04/2009; 34(6):830-2. DOI: 10.1364/OL.34.000830
Source: PubMed


We propose an all-optical intensity differentiation scheme based on cross-polarization modulation (XPolM) in a semiconductor optical amplifier (SOA) while demonstrating the absolute value of differential signal that can be obtained by the SOA-based XPolM of two parts with relative delay from the input signal and well extracted by the polarization filter. The differentiation errors and eye diagrams versus sampling time Delta are investigated for data rate at 12.5 Gbits/s, and the minimal error approximately 0.06 is achieved at Delta=0. Owing to a much faster polarization response, our scheme bears great potential for all-optical signal processing over 100 Gbits/s. By application of the differentiator, we further obtain the 20 GHz short pulse train with a pulse width of approximately 10 ps.

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    • "A photonic microwave temporal differentiator could be achieved based on PM and PM-IM conversion in an FBG serving as a frequency discriminator [14], [15]. A temporal differentiator using other schemes such as the XGM [16] and the XPolM [17] in a SOA has also been reported. "
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    ABSTRACT: A microwave bandpass differentiator implemented based on a finite impulse response (FIR) photonic microwave delay-line filter with nonuniformly-spaced taps is proposed and experimentally demonstrated. To implement a microwave bandpass differentiator, the coefficients of the photonic microwave delay-line filter should have both positive and negative coefficients. In the proposed approach, the negative coefficients are equivalently achieved by introducing an additional time delay to each of the taps, leading to a π phase shift to the tap. Compared with a uniformly-spaced photonic microwave delay-line filter with true negative coefficients, the proposed differentiator features a greatly simplified implementation. A microwave bandpass differentiator based on a six-tap nonuniformly-spaced photonic microwave delay-line filter is designed, simulated, and experimentally demonstrated. The reconfigurability of the microwave bandpass differentiator is experimentally investigated. The employment of the differentiator to perform differentiation of a bandpass microwave signal is also experimentally demonstrated.
    Journal of Lightwave Technology 11/2011; 29(22):3470-3475. DOI:10.1109/JLT.2011.2169939 · 2.97 Impact Factor
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    • "First-order and higher order differentiators of complex optical signals have been successfully demonstrated [1]–[9]; coherent differentiation has shown to be of scientific and practical significance for a wide range of applications, including generation of high-order Hermite–Gaussian pulse waveforms [1]–[12], ultrashort pulse shaping [13]–[15], and direct phase reconstruction of arbitrary optical signals [16]–[18]. On the other hand, incoherent photonic differentiators, operating on intensity time waveforms, have proven particularly useful for ultrawideband (UWB) microwave signal generation and processing [10]–[12], [19]–[21]. These last types of photonic differentiators can be considered as a direct all-optical equivalent to conventional electronic temporal differentiators since amplitude-only signals are actually processed in the electronic domain. "
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