Second-order Sideband Research Articles

Generation of second-order sidebands and slow–fast light in cavity magnomechanics with a parametric amplifier

In this work, we theoretically investigate the optical second-order sideband (OSS) efficiency and group delay of an output probe field in a two-coupled cavity magnomechanics (CMM) system. The setup comprises a gain (active) cavity and a passive (loss) cavity, which simultaneously includes an optical parametric amplifier (OPA) and a yttrium iron garnet sphere to facilitate magnon–photon coupling. Employing experimentally attainable parameters, we show that the presence of an OPA can significantly enhance the optical transmission rate and OSS efficiency. We show that photon–magnon strong coupling can enhance OSS efficiency substantially when compared to weak photon–magnon coupling. Our results, in particular, show that the OSS’s efficiency may be significantly improved for active–passive-coupled cavities as compared to the passive–passive cavities system. Furthermore, we demonstrate that modifying the system configurations may change the group delay, affecting the transition from rapid to slow light propagation, and vice versa. Our results provide a novel and easy approach to designing CMM devices for altering light propagation, with possible applications including optical switching, information storage, and accurate measurement of weak signals.

Modulation of Second-Order Sideband Efficiency in an Atom-Assisted Optomechanical System

We propose an efficient scheme to enhance the generation of optical second-order sidebands (OSSs) in an atom-assisted optomechanical system. The cavity field is coupled with a strong driving field and a weak probe field, and a control field is applied to the atom. We use the steady-state method to analyze the nonlinear interaction in the system, which is different from the traditional linear analysis method. The existence of an auxiliary three-level atom driven by the control field significantly enhances the generation of an OSS. It is found that the efficiency of the OSS can be effectively modulated by adjusting the Rabi frequency of the control field, optomechanical cooperativity and atomic coupling strength. Our scheme provides a promising solution for controlling light propagation and has potential application in quantum optical devices and quantum information networks.

Second-Order Sidebands and Group Delays in Coupled Optomechanical Cavity System with a Cubic Nonlinear Harmonic Oscillator

The generation of second-order sidebands and its associated group delay is an important subject in optical storage and switch. In this work, the efficiency of second-order sideband generation in a coupled optomechanical cavity system with a cubic nonlinear harmonic oscillator is theoretically investigated. It is found that the efficiency of second-order sideband generation can be effectively enhanced with the decrease in decay rate of optomechanical cavity, the increase in coupling strength between two cavities and the power of probe field. The slow light effect (i.e., positive group delay) is also observed in the proposed optomechanical cavity system, and can be controlled with the power of control field.

High-precision realization for sensing charged particles based on optomechanically induced two-color second-order sidebands

We propose an effective scheme to sense charged particles by employing two-color second-order sidebands (TSSs) in a hybrid optomechanical system. This is realized in an optomechanical cavity with a double-oscillator structure, where the Coulomb force acting on two charged oscillators participates in nonlinear optomechanical interaction. With the aid of mechanical mode splitting induced by the Coulomb force, we report that the TSS spectrum can be generated and enhanced when the strong absorption in the transmission spectrum allows the TSS generated pathways to be readily accessed. More importantly, after seeking two correlations between the TSS spectra and the charged particles deposited on the oscillator, we design a dual-parameter sensor to measure the mass and the charge of the external particles simultaneously. Through evaluating the influence of the thermomechanical noise on the optomechanical sensing device, the resolution for detecting the mass and the charge of the measured particles can be identified as δm≈1.7×10−18g and δQ≈1.6×10−18C, respectively.

Generation of Second-Order Sideband through Nonlinear Magnetostrictive Interaction

Nonlinear interaction between the magnon mode and the mechanical mode in a magnomechanical system is treated analytically where the magnon mode is coherently driven by a bichromatic microwave drive field consisting of a strong pumping field and a weak probe field and that works within a perturbative regime. Using experimentally achievable parameters, we show that the magnonic second-order sideband is generated and can be considerably enhanced by increasing the power of the pumping field. The suppression of the magnonic second-order sideband generation at the resonance point is discussed. Furthermore, the efficiency of magnonic second-order sideband generation can be well controlled by adjusting the applied bias magnetic field strength, which is a particular feature compared to the optical second-order sideband. In addition to offering insights into the magnomechanical nonlinearity, the present results have the potential to pave the way for exploring practical applications for achieving high-precision measurement in magnonics.

Magnon-squeezing-enhanced slow light and second-order sideband in cavity magnomechanics

Magnon-squeezing-enhanced slow light and second-order sideband in cavity magnomechanics

Modulation of the second-order sideband efficiency of a double-cavity optomechanical system by mechanical pumps

We study the effect of external mechanical pumps on the second-order sideband generation (SSG) efficiency in a double-cavity optomechanical system. The SSG efficiency can be tuned by changing the amplitude and phase of the mechanical pumps. When external mechanical pumps are applied to both mechanical resonators, the influence on the SSG efficiency is a superposition of the two mechanical pumps driven separately. The SSG efficiency can be increased up to three times with the application of mechanical pumps compared to the case without external mechanical pumps. The present investigation proposes a method that can be applied to more cavity cascades to achieve more desirable SSG efficiency and optimize nonlinear optical properties.

Higher-order sideband based on transparent windows in a two-cavity optomechanical system

We present a scheme to realize the regulation of single and double transparent windows in a two-cavity optomechanical device. By studying the output field through the two-cavity device, we not only show the transmission spectrum of the probe field and the second-order sideband process, but also analyze the physical mechanism of the induced transparency window and the efficiency of the second-order sideband process. Moreover, the optomechanically induced transparency window and the coupling of two cavities resulting in transparency window are discussed. We find that the transparency windows and the second-order sideband process can be modulated by the power of the control field and the coupling strength between two cavities. Our device is feasible for controlling light propagation, which might have potential application in quantum optical devices and quantum information networks.

Nonreciprocal sideband responses in a spinning microwave magnomechanical system.

Nonreciprocal sideband responses in a spinning microwave magnomechanical system consists of a spinning resonator coupled with a yttrium iron garnet sphere are proposed. We show that the efficiency of sideband generation can be enhanced in one driving direction but restrained in the opposite. This nonreciprocity results from Sagnac effect induced by the spinning resonator, leading to asymmetric magnonic responses in two different driving directions. Beyond the conventional linearized description, the properties of nonreciprocal two-color second-order sideband are demonstrated. By adjusting Sagnac-Fizeau shift and the power of control field, the degree of asymmetric magnonic responses can be strengthened, therefore causing stronger nonreciprocity of sideband. Especially, for the case of strong Sagnac-Fizeau shift and the control field, high level of efficiency and isolation ratio of sideband are achieved simultaneously and the operational bandwidth of strong nonreciprocity can be expanded. Our proposal provides an effective avenue for the manipulation of the nonreciprocity of sideband and has potentially practical applications in on-chip microwave isolation devices and magnon-based precision measurement.

Enhanced 4×4 MIMO RoF architecture for 5G mmWave indoor applications at 60 GHz unlicensed band

4×4 Multiple Input Multiple Output (MIMO) optical architecture based on Radio over Fiber (RoF) is proposed for 5G millimeter Wave (mmWave) indoor applications in the unlicensed 60 GHz band. First-order and second-order sidebands, generated by Dual-Drive Mach-Zehnder Modulator (DD-MZM), are exploited as optical subcarriers in order to reduce the number of Local Oscillators (LOs) implemented. Four MIMO-OFDM signals are multiplexed using Dual-Parallel Mach-Zehnder Modulator (DP-MZM) configured to perform Optical Carrier Suppression (OCS) modulation. 60 GHz spacing is ensured between each data signal and its corresponding subcarrier which allows simple heterodyne detection at Radio Access Point (RAP) level. In addition, we have proposed a 4×4 MIMO extension of Triple-S-and-Valenzuela (TSV) radio channel model based on geometrical approach. We demonstrate that the proposed RoF system with adequate configuration can meet the 5G New Radio (NR) requirement in terms of Error Vector Magnitude (EVM). Moreover, Bit Error Rate (BER) performance is evaluated with and without 5G NR channel coding, for transmission over 25 km of optical fiber followed by 3 m of radio channel, by exploiting the overall allocated band at 60 GHz which allows to achieve a very high data rate up to 122.5 Gb/s.

Photothermal effects on optical bistability and second-order sidebands in a cavity

We theoretically study the optical bistability and second-order sideband generation (SSG) in an optical cavity having photothermal effect in our paper. Using the perturbation method, we give an explicit analytical expression for SSG, showing a conversion efficiency of over 30. With change in the system parameters, our numerical method shows that the transparency window of the photothermal induced transparency and the SSG can be significantly enhanced by the photothermal effects. Our obtained results in this study can provide a reference to develop a new way in all-optical switching and precision measurement.

Generation of second-order sideband and slow-fast light effects in a PT-symmetric optomechanical system

We theoretically study the second-order sideband generation and slow-fast light effects in a parity-time (PT) symmetric optomechanical system, which consists of an active cavity and a passive cavity containing optical parametric amplifier (OPA). Compared to the double-passive nonlinear system, we find that the second-order sideband efficiency can be significantly enhanced by the tunneling strength in the PT-symmetric system with OPA. The flexible manipulation of the second-order generation also can be realized by modulating OPA gain and phase. Moreover, the fast and slow light effects in the optomechanical system are discussed. When the tunneling strength J=3κ1, the time of the second-order sideband group delay can be effectively prolonged in a PT-symmetric cavity in the presence of OPA. The results may have some guidance for the enhancement of second-order sideband efficiency, which has potential applications in optical communication and storage.

The second-order sideband enhancement in spinning resonators with an external phonon pump

The second-order sideband enhancement in spinning resonators with an external phonon pump

Tunable second-order sideband effects in hybrid optomechanical cavity assisted with a Bose–Einstein condensate

We theoretically investigated a second-order optomechanical-induced transparency (OMIT) process of a hybrid optomechanical system (COMS), which a Bose–Einstein condensate (BEC) in the presence of atom–atom interaction trapped inside a cavity with a moving end mirror. The advantage of this hybrid COMS over a bare COMS is that the frequency of the second mode is controlled by the s-wave scattering interaction. Based on the traditional linearization approximation, we derive analytical solutions for the output transmission intensity of the probe field and the dimensionless amplitude of the second-order sideband (SS). The numerical results show that the transmission intensity of the probe field and the dimensionless amplitude of the SS can be controlled by the s-wave scattering frequency. Furthermore, the control field intensities, the effective detuning, the effective coupling strength of the cavity field with the Bogoliubov mode are used to control the transmission intensity of the probe field and the dimensionless amplitude of the SS.

Two-color second-order sideband generation via magnon Kerr nonlinearity in a cavity magnonical system

We investigate the enhanced generation of the optical second-order sideband (OSS) via magnon Kerr nonlinearity from a cavity magnonical hybrid system consisting of a single small yttrium iron garnet (YIG) crystal sphere and a three-dimensional (3D) rectangular cavity driven with a weak probe and a strong control field. Beyond the linear approximation, we solve the nonlinear Heisenberg–Langevin equations for achieving the analytical solutions by employing the perturbation technique. Using the experimentally achievable parameter settings, we demonstrate that the OSS generation can be significantly enhanced via increasing the magnon Kerr nonlinearity even if the coupling between the cavity and magnon is weak. Interestingly, two-color OSS generation can be observed when the cavity-magnon coupling is in the strong-coupling regime, which results from the magnonical polaritons induced by the hybrid of cavity and magnon modes. The present results illustrate the potential to utilize magnon Kerr nonlinearity for enhancing optical higher-order sidebands and controlling optical frequency combs, as well as to guide the design of experimental implementation.

Enhanced second-order sideband via surface plasmon polaritons in a low-Q microcavity

We investigate the creation of the optical second-order sideband (OSS) from a hybrid system consisting of a single quantum dot (QD), a spherical metallic nanoparticle, and a low-Q microcavity driven with a weak probe and a strong control field. Beyond the conventional linearized description, we solve the nonlinear Heisenberg–Langevin equations for achieving the nonlinear coefficient of the OSS by employing the perturbation technique. It is shown that the hybrid of plasmon and cavity modes induces the formation of the surface plasmon polaritons, resulting in a controllable interaction that can be enhanced into a strong coupling regime even if the cavity–QD interaction is initially in the weak-coupling regime. As a result, enhanced OSS generation and the splitting of the transmission spectra can be observed. In addition, it is also shown that the size of the metal nanoparticle (MNP) has a profound effect on the output OSS spectrum, which might form a precision self-referenced detection scheme for extracting size information of the MNP.

Analysis of Optical Single Sideband Modulators for Radio Over Fiber Link with and without Second Order Sidebands

The analysis of Optical Single Sideband (OSSB) generation with and without second-order sidebands for Radio over Fiber (RoF) is presented. The performance of systems based on hybrid coupler with distinct phase angle and Dual-Parallel Dual-Drive Mach-Zehnder Modulator (DP-DDMZM) is compared using simulation. Impact of parameters like Single-Mode Fiber (SMF) length, Radiofrequency (RF) amplitude, and laser linewidth on Signal-to-Noise Ratio (SNR) has been investigated. It has been observed that eliminating one of the second-order sidebands with 120° hybrid coupler improves peak SNR in comparison to 90° hybrid coupler with both second-order sidebands and DP-DDMZM-based system without second-order sidebands irrespective of Continuous Wave (CW) laser linewidth.

Composite optical phase locking technology of chirp synthetic aperture lidar

An accurate chirp synthetic aperture lidar is proven, and the chirp laser signal is generated by an optical filter selecting specific sidebands from infinite sidebands, which are generated by laser signals passing through an electro-optic phase modulator driven by a chirp signal. And the bandwidth and chirp rate of the N-th order sideband is N times as large as the chirp signal by the signal generator. Then, a chirp signal with a modulation bandwidth of 1.2 GHz and a tuning rate of 12 THz/s is obtained by selecting the positive second-order sideband by an optical filter. Next, by adopting composite optical phase-locking processing, the random phase caused by the lidar system will be well offset, and the phase is stable within 0.1rad. Finally, Laboratory imaging results show that the azimuth resolution of synthetic aperture lidar is better than 0.04 m. In the future, by applying the higher-order sideband, higher tuning rates and bandwidths can be expected.

Photonic broadband signal frequency conversion and bandwidth multiplication based on a Fourier domain mode-locked optoelectronic oscillator

A photonic broadband signal frequency conversion and bandwidth multiplication system is demonstrated based on a Fourier domain mode-locked optoelectronic oscillator (FDML-OEO). In this method, frequency conversion is achieved by using the selected optical sideband as the optical source of the FDML-OEO. An experiment is conducted, and a linear frequency modulation (LFM) signal with different central frequencies are converted. The central frequency of the converted signal can be tuned simply by adjusting the wavelength of the optical carrier. Due to the feature of low phase noise of the OEO, the degradation of the converted signal is almost neglected. Broadband signals with different time widths are also converted in terms of fibre length regulation. Furthermore, bandwidth multiplication of the LFM signal is achieved by selecting a second-order optical sideband as the optical source of the FDML-OEO.

Robust Four-Wave Mixing and Double Second-Order Optomechanically Induced Transparency Sideband in a Hybrid Optomechanical System

We theoretically research the four-wave mixing (FWM) and second-order sideband generation (SSG) in a hybrid optomechanical system under the condition of pump on-resonance and pump off-resonance, where an optomechanical resonator is coupled to another nanomechanical resonator (NR) via Coulomb interaction. Using the standard quantum optics method and input–output theory, we obtain the analytical solution of the FWM and SSG with strict derivation. According to the numerical simulations, we find that the FWM can be controlled via regulating the coupling strength and the frequency difference of the two NRs under different detuning, which also gives a means to determine the coupling strength of the two NRs. Furthermore, the SSG is sensitive to the detuning, which shows double second-order optomechanically induced transparency (OMIT) sidebands via controlling the coupling strength and frequencies of the resonators. Our investigation may increase the comprehension of nonlinear phenomena in hybrid optomechanics systems.