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The output powers coupled into the fiber versus increased and decreased IFP as solid and dashed lines, respectively, at TEC temperatures of 280, 285, 290, 295, and 305 K.
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All-optical flip-flop has been demonstrated experimentally based on our optical bistable hybrid square-rectangular lasers. In this paper, dual-mode rate equations are utilized for studying the optical bistability in the two-section hybrid-coupled semiconductor laser. A phenomenological gain spectrum model is constructed for considering the mode com...
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In this paper, we proposed a model based on Rydberg atoms for controlling the optical bistability (OB) and optical multistability (OM) in a ring cavity. The atoms interact with an elliptical polarized probe light and a strong coupling light in the presence of external magnetic field. We realized that the threshold of OB can be controlled by ellipti...
Citations
... Recently, a hybrid square-rectangular laser (HSRL) with a square microcavity and a FP cavity was designed and fabricated to realize stable single-mode operation [31,32]. Based on the saturable absorbability of the square microcavity, a two-section dual-mode rate equation model was set up to study the optical bistability of the HSRL and the operation of all-optical flip-flop was numerically analyzed [33]. Experimentally, an all-optical switch with a wide wavelength tolerant range was obtained, and all-optical multiple logic gates were implemented based on the mode competitions under the injection of low-power optical pulses [34]. ...
... Based on the mode competition characteristic of the HSRL, all-optical logic gates are simulated by optical signal injection at the side modes to suppress the dominant lasing mode. With optical injection terms for two side modes, we can establish the rate equations of the carrier densities and the photon densities in the HSRL similar to [33]: ...
... Finally, the simplified gain spectrum model including the nonlinear gain in [33] is modified to account for the effect of temperature rise T more exactly. According to the relationship between material gain spectrum and spontaneous emission spectrum, the phenomenological gain spectrum is considered as [36,37] ...
All-optical switch and multiple logic gates have been demonstrated using a hybrid-cavity semiconductor laser composed of a square microcavity and a Fabry–Perot cavity experimentally. In this paper, two-section tri-mode rate equations with optical injection terms are proposed and applied to study all-optical logic gates of NOT, NOR, and NAND operations utilizing the hybrid-cavity laser. Steady-state and dynamical characteristics of all-optical multiple logic gates are simulated, taking into account the influence of mode frequency detuning, gain suppression coefficients, mode Q factor, injection energy, and biasing current. All-optical logic NOT, NOR, and NAND gates up to 20, 15, and 20 Gbit/s are obtained numerically with dynamic extinction ratios of over 20, 20, and 10 dB, respectively, which are potential response speeds of the all-optical logic gates based on the hybrid-cavity semiconductor lasers.
... Furthermore, mode competition can flatten the chaotic signal due to the enhancement of low-frequency energy. The hybrid-cavity lasers formed by a whispering gallery mode microcavity and a Fabry-Perot (FP) cavity have been investigated for realizing single-mode laser and all-optical signal processing with optical bistability [23][24][25][26][27][28]. Here we design a hybrid square/rhombus-rectangular laser (HSRRL), as shown in the inset of Fig. 1, where the square/rhombus microcavity (SRM) works as a wavelength selective reflector for the FP cavity with high reflectivity related to the mode in the SRM. ...
In this Letter, we design and realize a hybrid-cavity laser with single- or dual-mode lasing states and study the nonlinear states of the laser under external optical feedback (EOF). The laser at a dual-mode state easily and directly enters the chaotic state without periodic oscillation states and display chaos for a much wider range of the EOF magnitude than the laser at a single-mode state. A flat chaotic signal is obtained for the laser at a dual-mode lasing state under a weak EOF benefitting from the low-frequency energy enhancement caused by mode competition between the dual modes.
We report the latest development in high-speed directly modulated tunable laser based on simple and compact hybrid square/rhombus-rectangular laser (HSRRL), aiming for low-cost deployment in next generation high-throughput optical interconnects, intra-/inter-data center networks, and optical fiber communication system. The HSRRL is composed of a deformed square whispering gallery mode (WGM) microcavity and a Fabry–Pérot (FP) cavity, and the WGM microcavity is used as an end face of the FP cavity with mode selection. A deformable WGM microcavity is designed to obtain a high reflectivity. The HSRRL, fabricated with deep-etching processing steps similar to FP laser without grating or epitaxial regrowth, has achieved 7-mA threshold current, 0.4-mW/mA slope efficiency, above 52-dB side mode suppression ratio (SMSR), and 16.2-GHz modulation bandwidth with injection currents of 34.3 mA and 60 mA for WGM microcavity and FP cavity, respectively. A wavelength tuning from 1537.40 nm to 1570.42 nm is realized by adjusting the injection currents simultaneously. In the tuning range, the laser has an SMSR greater than 40 dB, a linewidth less than 4 MHz, and a 3-dB modulation bandwidth greater than 14 GHz.
Low relative intensity noise (RIN) was demonstrated experimentally for hybrid square-rectangular lasers (HSRLs). In this paper, RIN of the HSRL is numerically simulated and the laser linewidth is investigated theoretically and experimentally. The non-zero delayed self-heterodyne method is utilized to measure the linewidth, and the laser linewidth of 2.9 MHz is obtained experimentally. A two-section single-mode rate equation model including Langevin noise sources is established to study the noise characteristics theoretically. The time-varying mode photon density and frequency are simulated, then the intensity and frequency noise (FN) spectra are calculated. With the rising of bias currents, RIN decreases and approaches the standard quantum limit. Large mode
Q
-factor, high bias current, and passive square microcavity are effective methods to reduce FN and linewidth of the HSRLs. By inducing a passive square microcavity, we can expect a low linewidth of 37 kHz for the hybrid-cavity laser with
Q
= 1.17 × 10
<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup>
.
A hybrid‐cavity laser composed of a whispering‐gallery‐mode (WGM) microcavity and a Fabry–Perot (FP) cavity has been proposed and demonstrated for improving the characteristics of single‐mode operation and realizing high‐speed all‐optical switching. The reflectivity spectra for a square microcavity as one side reflector of the hybrid cavity are simulated, which shows high reflectivity around high‐Q WGMs. The mode Q‐factor enhancements are numerically and experimentally demonstrated for the hybrid modes between the WGM of square microcavity and FP modes. High‐performance single‐mode laser is obtained with side mode suppression ratio (SMSR) as high as 47 dB, and single‐mode lasing with SMSR larger than 40 dB over wide variations of the injection currents indicates the robustness of single‐mode operation, by applying currents to the square microcavity and the FP cavity at the same time. Furthermore, two types of optical bistability are demonstrated as the square microcavity is unbiased, due to saturable absorption in the microcavity section and mode competitions, respectively. High‐speed all‐optical switching and logic operations are realized using the on–off bistability around the threshold current and mode competition bistability above the threshold. In addition, all‐optical multiple logic gates with NOT, NOR, and NAND functions are verified under low‐power optical pulses.
In this study, optical bistability and multistability phenomena are numerically investigated in the terahertz frequency domain based on the quasiperiodic photonic metamaterial multilayers, in which both the regular positive index and special negative index materials are artificially arranged, according to the interesting Fibonacci sequence structure. In order to obtain the tunable bistability and multibistability behaviors, the Kerr-type nonlinear dielectric layer and graphene sheet are sandwiched between two Fibonacci quasiperiodic one-dimensional photonic crystals. Results show that the intensity-dependent hysteresis curves including bistability and multistability are thoroughly discussed by judiciously changing the systematical parameters such as the frequency of incident wave, thickness of each layer, incident angle, as well as the chemical potential of graphene which can produce strong influences on the switch-up/down threshold values and widths of hysteresis loops.
All-optical switching and multiple logic gates are experimentally demonstrated using AlGaInAs/InP hybrid square-rectangular lasers. Controllable bistability induced by saturable absorption in the square microcavity is achieved around the threshold with the square cavity in an open circuit state. Based on the bistability, all-optical switching operation is realized by injecting set/reset optical signals with the wavelengths around the lasing mode of 1529.9 nm and another high-Q mode at 1560 nm. Furthermore, mode competitions between three resonant modes around 1541 nm with an interval of 1.2 nm are used to realize all-optical multiple logic gates of NOT, NOR and NAND functions under low-power optical pulses, with injecting currents to the square and rectan-gular sections. The static extinction ratio of 34 dB, 40 dB and 24 dB are obtained for NOT, NOR and NAND gates, respectively, and the dynamic extinction ratio over 10 dB of NOT function at 15 Gb/s, NOR and NAND functions at 2 Gb/s are demonstrated. With the merits of multifunctional operations, large optical injection wave-length tolerant ranges, low power consumption, small footprint and suitability for on-chip integration, the device offers a potential solution for all-optical signal processing in photonic integration circuits.
