Microwave Photonic Channelizer With Large Instantaneous Bandwidth Based on AOFS

Abstract

The microwave photonic channelizer can convert the RF signal into the optical domain for transmission and procession, effectively avoiding the limitation of electronic bottleneck, and realizing the instantaneous reception of ultra-wideband signal or multi-frequency signals, which can be perfectly applied to radar system and electronic warfare. In this paper, a microwave photonic channelizer based on dual-output image-reject mixer is proposed, both the signal path and the local oscillator path are divided into three paths by using an optical coupler. An acousto-optic frequency shifter (AOFS) is used by the optical local oscillator to shift the frequency to the left and right and then enters the image rejection mixer with the signal path. Finally, a 6 GHz bandwidth RF signal is divided into six subchannels with a bandwidth of 1 GHz to achieve simultaneous reception. This scheme needs no optical frequency comb and doubles the channelization efficiency, the image rejection ratio of the sub-channels is about 22 dB, and the spurious-free dynamic range of the system can reach 103.2 dB• Hz 2∕3 .

Review of Microwave and RF Photonic Channelizers using Optical Kerr Microcomb Sources

“…In recent years, channelization schemes based on LO frequency shifting/scanning have been proposed, typically using acousto-optic frequency shifters (AOFS) [15] and injection locking [69] [14]. As shown in Fig.…”

“…In addition to the injection locking mentioned above, the LO frequency shifting can also be implemented by AOFS, where the shifted signal is fed to the I/Q coherent receiver along with the modulated signal, and finally the broadband RF signal is split into six subchannels for output [15]. In some studies, the round-trip time of the cyclic frequency-shifting loop was varied by controlling the duration of a single pulse through the optical 5 switch to ensure that each frequency is within the appropriate time window, similar to wavelength scanning, to achieve multiple RF channels serial in the time domain [16].…”

“…Obviously, the stability and accuracy of the filter are not specified, which reduces the complexity of the system. In recent years, wavelength scanning has been achieved by external laser source injection locking [14], acousto-optic frequency shifters (AOFS) [15], and optical switches [16]. Each wavelength marks a specific RF channel, which is then received serially by a low-speed photodetector.…”

Review of Photonic RF Channelizers based on Optical Microcombs

“…In recent years, channelization schemes based on LO frequency shifting/scanning have been proposed, typically using acousto-optic frequency shifters (AOFS) [15] and injection locking [69] [14]. As shown in Figure 1(e), a broadband RF signal is first modulated onto an optical carrier, while the LO comb is generated by electro-optic modulation.…”

Review of Microwave Photonic RF Channelizers based on Optical Kerr Microcombs

“…In addition to the injection locking mentioned above, the LO frequency shifting can also be implemented by AOFS, where the shifted signal is fed to the I/Q coherent receiver along with the modulated signal, and finally the broadband RF signal is split into six subchannels for output [15]. In some studies, the round-trip time of the cyclic frequency-shifting loop was varied by controlling the duration of a single pulse through the optical switch to ensure that each frequency is within the appropriate time window, similar to wavelength scanning, to achieve multiple RF channels serial in the time domain [16].…”