40-Gb/s Polarization-Insensitive All-Optical Clock Recovery Using a Quantum-Dot Fabry–PÉrot Laser Assisted by an SOA and Bandpass Filtering
ABSTRACT We experimentally demonstrate polarization-insensitive all-optical clock recovery using a passively mode-locked quantum-dot Fabry-Perot (QD-FP) semiconductor laser at 40 Gb/s. Polarization insensitivity is achieved by using a wavelength conversion stage based on cross-phase modulation in a semiconductor optical amplifier and optical bandpass filtering. A clock signal with a root-mean-square timing jitter of 300 fs is recovered for an input data signal with a scrambled state-of-polarization (SOP). This is comparable to that from the QD-FP laser alone for an input signal with a fixed SOP. Moreover, an improvement in the tolerance to a degradation in the optical signal-to-noise ratio of the input signal is achieved by the use of the wavelength conversion stage.
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ABSTRACT: High-speed all-optical clock recovery using a two-section gain-coupled distributed feedback laser is demonstrated operating in the coherent and the incoherent modes. It is found that the coherent mode has a much better performance compared with the incoherent mode. The performance of the coherent clock recovery scheme at 12 and 40 Gb/s, including wavelength and polarization insensitivity, timing jitter, and phase noise; power penalty; sensitivity; dynamic range; locking bandwidth; detuning range of the injection wavelength; and lockup time are described in detail. A comparison between the performances of the two modes of operation is also presented.Journal of Lightwave Technology 10/2002; 20(9):1705- 1714. · 2.56 Impact Factor
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ABSTRACT: This paper reports on timing-jitter analysis of an all-optical clock-recovery scheme at 40 GHz using self-pulsating (SP) lasers. Based on the analogy with injection locking of oscillators, theoretical investigations on phase-noise properties of the recovered clock lead to the demonstration of a filtering function with slope that is compliant with the International Telecommunications Union (ITU) standards and allow us to underline the dependence of the cutoff frequency of the filtering transfer function on the spectral linewidth of the free running SP laser. From this phase-noise analysis, an analytical expression of the timing jitter of the recovered clock is derived, including the optical signal-to-noise ratio (OSNR) of the injected signal. A set of experiments on all-optical clock recovery at 40 GHz is then presented and demonstrates the crucial role of the spectral linewidth on the timing-jitter-filtering function of the SP laser. In good agreement with theoretical results, the impact of the OSNR degradation of the injected signal on the timing jitter is also demonstrated. Finally, the all-optical clock-recovery operation using a quantum-dot SP laser is shown to be standard compliant in terms of timing jitter, even for highly degraded OSNR.Journal of Lightwave Technology 11/2006; 24(10):3734-3742. · 2.56 Impact Factor
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ABSTRACT: We report on the experimental assessment of an all-optical clock-recovery scheme at 40-Gb/s cascading a polarization-insensitive bulk-based self-pulsating (SP) laser and a high spectral purity quantum-dots-based SP laser. It is demonstrated experimentally that such a clock-recovery scheme is polarization insensitive, efficient in the jitter filtering, and tolerant for an input optical signal-to-noise ratio (OSNR) as low as 15 dB/0.1 nm. It is shown theoretically that the jitter-filtering function of the cascade is the product of the transfer functions of both lasers. The contributions of the phase noise of these two lasers to the final jitter are also identified and quantified. The influence of the degradation of the OSNR to the total timing jitter is also analyzed. The approach proposed in this paper offers the real opportunity to realize an all-optical clock recovery with a performance compatible for system applicationsJournal of Lightwave Technology 02/2007; · 2.56 Impact Factor