Based on chaos synchronization between two 1550 nm response vertical-cavity surface-emitting lasers (R-VCSELs), we propose and numerically investigate a bidirectional dual-channel chaotic secure communication system. Under delayed dual-path chaotic signal injections from the injection VCSEL (I-VCSEL) with polarization-preserved optical feedback, a driving VCSEL (D-VCSEL) can generate an optimized chaotic signal, which can drive two R-VCSELs to output polarization-resolved chaotic signals with wide bandwidth about 35 GHz and low TDS below 0.1 in a relatively large parameter range. Moreover, high-quality isochronal chaos synchronization between the corresponding linear polarization components of two R-VCSELs can be achieved. In contrast, the synchronization quality between D-VCSEL and arbitrary one R-VCSEL is inferior. On this basis, through the polarization-division-multiplexing technique in conjunction with the chaos modulation (CM) method, this proposed system can realize security-enhanced bidirectional dual-channel message transmission of 30 Gbps bipolar non-return-to-zero signals over a 140 km fiber link with Q-factors above six. After adopting four-level pulse amplitude modulation, 60 Gbps signals can be successfully transmitted over a 60 km fiber link with Bit-Error-Rates (BERs) below the hard-decision forward error correction (HD-FEC) threshold of 3.8×10-3.
KEYWORDS: Logic, Signal to noise ratio, Vertical cavity surface emitting lasers, Simulations, Quantum optical ring resonators, Microresonators, Signal intensity, Polarization, Optical resonators, Fire
In this paper, we propose an all optical JK flip-flop system consisting of three vertical-cavity surface-emitting lasers with embedded saturable absorber (VCSEL-SAs) is proposed and numerically simulated. Also, the effects of injection intensity, delay and noise on the JK flip-flop are numerically analyzed. The results show that, based on the spiking dynamics of excited VCSEL-SA, the proposed all-optical JK flip-flop model can perform all the fundamental functions of conventional JK flip-flop under suitable bias current, injection intensity and perturbation delay between two trigger signals. Moreover, the noise has a little effect on the performance of JK flip-flop, but the proposed system has good robustness to the noise. The results provide a feasibility for the application of VCSEL-SA devices in the future ultrafast neuromorphic computing systems.
Based on two Response Vertical-Cavity Surface-Emitting Lasers (R-VCSELs) subject to identical chaos optical injection with phase modulation and dispersion compensation, we propose and numerically investigate a high-speed bidirectional chaotic secure communication system. The driving VCSEL (D-VCSEL) is used to generate the injected chaotic signals to two R-VCSELs. After introducing the phase modulation and dispersion compensation into injection path, the bandwidth of chaotic carrier from the linear polarization components of R-VCSEL1 and R-VCSEL2 can be extended to 45GHz, and corresponding Time Delay Signatures (TDSs) can be suppressed to about 0.15. Moreover, high-quality chaos synchronization between corresponding polarization components of two R-VCSELs but very low correlation between the D-VCSEL and any R-VCSEL can be achieved. On this basis, the bidirectional dual-channel information transmission of 30 Gbit/s over 100 km fiber link is successfully realized.
Due to many advantages of compact structure, high efficiency, good beam quality, etc., diode-pumped all-solid-state passively Q-switched lasers have a bright future in military, industrial processing, medicine, and other fields. At present, the relevant reports on diode-pumped all-solid-state passively Q-switched lasers mainly focus on the characteristics of the period-1 dynamic state, while there are few reports on the characteristics of other nonlinear dynamic states. In this work, we experimentally investigated the dynamic characteristics of a diode-pumped all-solid-state passively Q-switched Nd:LaMgAl11O19 laser by using a semiconductor saturable absorber mirror. The experimental results show that, under different absorbed pump power and cavity loss, the laser can display various dynamic states such as period-1, period-2, period-4, period-5, period-7, and chaotic pulsing states. Through changing the cavity loss, the laser goes through period- 1, period-2, period-4 to chaos, or period-1, period-5, period-7 to chaos.
We have experimentally investigated the generation of tunable and broadband Optical Frequency Comb (OFC) based on a gain-switching vertical-cavity surface emitting laser driven by a square wave signal under optical injection. During the experiment, the influences of modulation frequency fm and injection light wavelength λion OFC performances are analyzed systematically. The experimental results indicate that under suitable operation parameters, an OFC with bandwidth of 77.0 GHz within 10 dB power variation and single sideband phase noise of -115.7 dBc/Hz @ 10 kHz can be generated. Also, during the modulation frequency range of 1.5 GHz - 2.8 GHz, broadband OFCs with bandwidth exceeding 70.0 GHz can be obtained based on the square-current modulated VCSEL under optical injection.
We experimentally investigated multi-channel chaos synchronization characteristics based on two asymmetrical mutually coupled Weak-Resonant-Cavity Fabry-Perot Laser Diodes (WRC-FPLDs). Experimental results show that, through adjusting the center wavelength of the Tunable Optical Filter (TOF) and the injection power, different modes can be selected and induced into chaotic state with wideband. Under proper asymmetrical injection power and frequency detuning, stable leader-laggard chaos synchronization with the maximal correlation coefficient about 0.90 between two asymmetrical mutually coupled WRC-FPLDs can be achieved. In addition, the effects of injection power and frequency detuning between the two lasers on chaos synchronization performance have also been discussed.
Based on a vertical-cavity surface-emitting laser with saturated absorber (VCSEL-SA) subject to optical injection, we proposed an ultrafast pattern recognition scheme of four-bit binary data and theoretically investigated the recognition performances. The results show that, patterns recognition of different four-bit binary data at Gb/s rate can be realized by adjusting the injection weight of each bit number and optimal weight values can be determined. Although noise has some influences on the patterns recognition speed and accuracy, this proposed system has a certain robustness to noise on the whole. These results provide a promising application prospect for VCSEL-SA based ultrafast photonic neuromorphic system in pattern recognition field.
Based on a four-level rate equation model, we numerically simulated the nonlinear dynamics of a diode-pumped solidstate passively Q-switched laser. A Nd:YAG and a Cr4+:YAG is used as the gain medium and the saturable absorber in this system, respectively. Through setting the pumping rate or the round-trip optical loss at different values, the diodepumped solid-state passively Q-switched Nd:YAG/Cr4+:YAG laser may operate at the period-one, period-two, multiperiod or chaotic states. For a certain specific state, the time series, the power spectra and the Poincaré maps are represented. Moreover, the route for the diode-pumped solid-state passively Q-switched Nd:YAG/Cr4+:YAG laser entering into chaos is revealed by mapping the bifurcation.
We proposed a reconfigurable all-optical logic gate (AND, OR) based on a vertical-cavity surface-emitting laser with saturated absorber (VCSEL-SA) subject to dual pulse injection and numerically investigated the effects of injection delay, injection strength and bias current on the system performance. The results show that, through adjusting bias current, the pulse injection strength and the injection delay between two pulses, the reconfigurable all-optical logic gate (AND, OR) can be realized. For a suitable injection intensity, all-optical logic AND and OR gates can be implemented within a certain bias current range. Moreover, both AND and OR gates have good robust to noise under suitable injection strength. These results are expected to open a new window for future ultra-fast neuromorphic computing systems to solve complex classification and decision-making tasks
In this paper, we propose and numerically demonstrate a security-enhanced high-speed chaotic communication system by introducing phase modulation and phase-to-intensity conversion. The driving laser (DL) with delayed optical feedback can be used to generate the chaotic driving signal, which is simultaneously injected into two response lasers (RLs) through a phase modulator (PM) and a dispersion component (De). The simulated results show that, due to the phase modulation and phase-tointensity conversion, TDS of injected chaos signal from DL can be effectively suppressed and its bandwidth can be increased to 39.6 GHz under suitable parameter conditions. Simultaneously injecting the chaos signal into two identical RLs, high-quality chaos signals with weakened TDS and enhanced bandwidth between two RLs can be achieved even under certain parameter mismatches, but the synchronization quality between DL and any one of RLs is extremely bad. Based on the system synchronization, secure transmission of 20 Gbit/s messages can be realized and the transmission distance can be over 200km.
We experimentally demonstrate a diode-pumped passively Q-switched Yb:Lu3Al5O12 ceramic laser operating at 1031 nm or 1047 nm based on a semiconductor saturable absorber mirror (SESAM) and an output coupler (OC) of different transmission (T). For an OC of T=7.5% and an absorbed power of 9.25 W, the laser operates at 1031 nm with a maximum average output power of 1.47 W, the corresponding optical-to-optical efficiency of 15.85%, and the slope efficiency of 19.04%, respectively. The pulse width and the pulse repetition frequency (PRF) are about 1.23 μs and 245.04 kHz, respectively. For an OC of T=1.6% and an absorbed power of 9.25 W, the laser operates at 1047 nm with a maximum average output power of 0.85 W, the corresponding optical-to-optical efficiency of 9.21%, and the slope efficiency of 8.43%, respectively. The pulse width and the PRF are 1.49 μs and 112.63 kHz, respectively.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.