ObjectiveSince the "Einstein-Podolsky-Rosen (EPR) paradox" was proposed by Einstein, Podolsky and Rosen in the early 20th century, quantum entanglement has become key to understanding non-local and non-classical correlations based on the quantum mechanics. The entangled sideband modes represent a vital quantum resource, enabling multi-channel, high-capacity quantum information processing by actively distributing sideband modes across multiple nodes within a quantum system. A large number of entangled sideband modes are generated through optical parametric down-conversion. However, the extraction and manipulation of vacuum sideband modes present significant challenges. Therefore, a simple sideband modes control scheme is needed desperately for easier integration and application.MethodsThis paper presents a frequency-comb-type seed beam injection control scheme to generate a coherent beam with the same frequency and convert the vacuum entangled sideband modes to bright optical modes. We employed a fiber-coupled wave-guide amplitude modulators (WGAM) based on Mach-Zehnder interferometer structure to generate the frequency-comb-type seed beam and the modulated frequency equals to the free spectral range of the optical parametric oscillator (OPO). By precisely adjusting the bias voltage of the WGAM, the 1^st to 3^rd sideband modes are simultaneously output. All of the modes are parametric amplification taking advantage of the phase-matching relationship in the OPO, which determined the signal to noise (SNR) of the squeezed angle locked error signal remains constant.The broadband squeezed state, which involves many EPR entangled modes at the symmetric sidebands of around the half-pump frequency, are generated by pumping the nonlinear crystal. The ring filter cavity (RFC) as the frequency beam splitter are utilized to separate the entangled sideband modes, the upper sideband modes resonate while the lower sideband modes reflect. The RFC is the near-impedance matching cavity, which could efficiently separate the sideband modes and reduce the decoherence. The separated sideband modes are interfered with the corresponding LOs on a 50/50 beam splitter and directed toward two pairs of balanced homodyne detectors (BHDs) to detect the correlation noise.Results and discussionsThe OPO is locked in the parametric amplification status for the entangled state controlling, in which the carrier and each order entangled sideband mode are amplified. Combined with efficient mode filtering, low-loss feedback control, and time-delay compensation techniques, we achieve stable control and efficient detection of entangled sideband modes. The optimal correlation noise variances of the first- to third-order entangled sideband modes are detected by employing narrowband and high-gain BHDs. The quadrature amplitude correlated noise variances are 7.8 dB, 7.8 dB, 7.7 dB, respectively, while the quadrature phase correlated noise variances are 7.8 dB, 7.6 dB, 7.5 dB. We also show the noise spectrum in 1～15 MHz frequency band of the multiple-orders entangled sideband modes.ConclusionsIn summary, we have experimentally demonstrated three pairs of entangled sideband modes by employing the frequency-comb-type seed beam injection scheme. The frequency-comb-type seed beam was generated by a waveguide amplitude modulator and then injected into OPO. By parametrically amplifying the three pairs of entangled sideband modes, the entangled sideband modes are actively controlled. This scheme provides a straightforward method for the control of sideband modes, which can be further applied to achieve the multi-channel multiplexing quantum communications.