A photonic frequency downconverter based on a single dual-drive Mach-Zehnder modulator

Abstract

A novel photonic frequency downconverter is proposed and demonstrated using a single dual-drive MachZehnder modulator (DMZM). In the proposed scheme, the local oscillator (LO) and radio frequency (RF) signals are sent to the two RF ports of the DMZM, respectively. By biasing the modulator at the minimum transmission point, a downconverted intermediate frequency (IF) signal with the RF and LO components suppressed is obtained. An experiment is carried out to demonstrate the feasibility of the downconverter. Results show that a 30-GHz RF signal with 50-Mbaud 16 quadrature amplitude modulation (QAM) is successfully downconverted to the 2.4-GHz IF band. The error vector magnitude (EVM) of the downconverted signal is less than 2.0%.

Efficient Photonic Microwave Mixer With Compensation of the Chromatic Dispersion-Induced Power Fading

“…will be maximized and the unwanted RF and LO signals will be suppressed, which has been experimentally verified in [18]. However, the mixer in [18] is only used for frequency down-conversion without fiber transmission.…”

“…2. Schematic of the photonic microwave mixer based on a dual-electrode Mach-Zehnder modulator (DEMZM) [18]. SMF: single mode fiber.…”

“…Another solution is to integrate the parallel EMs and the optical coupler to achieve stable coherent interference. So far, some types of integrated modulators, such as dual-electrode Mach-Zehnder modulator (DEMZM) [18], [19], bidirectional MZM [20], dual-parallel MZM (DPMZM) [21]- [24] and dual-polarization quadrature phase-shift keying (DP-QPSK) modulator, are all commercially available and can be used as parallel EM mixers. A major drawback of the integrated parallel EM mixer is that the RF and LO signals cannot be separated using fiber.…”

“…Similar to the mixer in [18], an integrated DEMZM is used, since it has only one direct current (DC) bias and is simpler in operation than other parallel-structure modulators. The two electrodes of the DEMZM are driven by the RF and LO signals, respectively.…”

“…The two electrodes of the DEMZM are driven by the RF and LO signals, respectively. However, there are two novelties compared to [18]. Firstly, the phase difference of the RF and LO modulated sidebands can be simply adjusted by the DC bias of the modulator, thus the power fading caused by the fiber dispersion can be compensated.…”