Query: DMZM

title: Photonic microwave frequency shift keying signals generation based on a PM DMZM
abstract: A photonic microwave FSK signal generator is proposed based on a PM DMZM The proposed signal generator features on very simple structure and great frequency tunability. Experiments are conducted to validate the feasibility of the generator.

title: Photonic assisted microwave phase shifter using a DMZM and an optical bandpass filter.
abstract: We propose and demonstrate a photonic assisted wideband 360deg microwave phase shifter based on a conventional dual drive Mach Zehnder modulator (DMZM) and an optical bandpass filter (OBPF) The two arms of the DMZM are driven by the fundamental microwave signal to be phase shifted and its frequency doubled component, respectively. The OBPF followed after the DMZM is used to remove the optical carrier and the sidebands at either side of the optical carrier. As a result, only two sidebands corresponding to the fundamental microwave signal and its frequency doubled component, respectively, are left. Moreover, the phase shift between the two sidebands can be continuously tunable by adjusting the bias voltage of the DMZM. This phase shift is mapped to the fundamental microwave signal which is recovered by beating the two sidebands in a photodetector (PD) The proposed approach is theoretically analyzed and experimentally verified.

title: Equivalent photonic switch for microwave frequency shift keying signal generation.
abstract: A photonic microwave frequency shift keying (FSK) signal generator is proposed and experimentally demonstrated based on an equivalent photonic switch (EPS) The EPS is constructed using a polarization multiplexing dual drive Mach Zehnder modulator (PM DMZM) By properly controlling the data sequences and RF signals applied to the PM DMZM, microwave FSK signals with flexible frequency intervals can be obtained. The proposed FSK signal generator features the advantages of a simple structure, low loss, good stability, and great frequency tunability. In addition, the proposed setup can also be easily reconfigured to generate microwave amplitude shift keying and phase shift keying signals. The experimental results show that 2 Gb/s at 5/14 GHz and 1 Gb/s at 6/20 GHz microwave FSK signals are successfully generated, after transmission over 5 km single mode fiber. The required received optical power at 7% forward error correction threshold is only 14.48 dBm.

title: Stable radio frequency transfer over fiber based on microwave photonic phase shifter.
abstract: We demonstrate a radio frequency (RF) phase stable transmission over fiber based on microwave photonic phase shifter. In the proposed system, both assistant RF signals are applied to drive two arms of a dual drive Mach Zehnder modulator (DMZM) respectively. An optical bandpass filter is followed to filter out the first order sideband of optical modulated signal. Due to the phase independence between two optical sidebands, the phase perturbation caused by fiber length variations can be compensated automatically via controlling the direct current bias voltage of the DMZM. We have performed RF transfer in a 155 km single mode fiber with a frequency instability of 3.05 x 10 17 at 10,000 s averaging time.

title: Microwave photonic phase tunable mixer.
abstract: Traditional microwave photonic systems cannot implement frequency up conversion with phase tunable capability, which plays an important role for phase array beamforming. Here, a method that can implement both upconversion and downconversion with a broadband full degree phase shift capability by constructing an optical path with a Hilbert transform function is presented. Owing to the Hilbert transform path, the dual drive Mach Zehnder modulator (DMZM) bias information, which initially influences the amplitudes of the output signals, are transferred to their phases. As a result, the phase shift capability of the output radio frequencies (RFs) and intermediate frequencies (IFs) can be achieved by simply adjusting the bias voltage of the DMZM without using an optical filter. Experimental results demonstrate that a 360deg phase shift can be achieved when the IF signal below 4 GHz and the RF signal between 8 and 16 GHz are converted into each other.

title: Photonic downconversion with tunable wideband phase shift.
abstract: A microwave photonic frequency downconversion system with wideband and continuous phase shift function is proposed and experimentally demonstrated. In the proposed system, a radio frequency (RF) and a local oscillator (LO) signal drive two arms of a dual drive Mach Zehnder modulator (DMZM) A fiber Bragg grating (FBG) is used for reflecting the first order sidebands of both RF and LO signals. Due to phase independence between RF and LO optical sidebands, the phase shifting operation for an output intermediate frequency (IF) signal can be implemented either by adjusting the bias voltage of DMZM or by controlling the optical wavelength of laser. Experimental results demonstrate a full 0deg to 360deg phase shift, while an RF signal between 12 GHz to 20 GHz is downconverted to IFs below 4 GHz. The phase deviation is measured less than 2deg, and the fluctuation of magnitude response is measured less than 1 dB over a wideband frequency range.

title: Full duty triangular pulse generation based on a polarization multiplexing dual drive Mach Zehnder modulator.
abstract: A simple and flexible photonic approach to generating a triangular microwave waveform using a single integrated polarization multiplexing dual drive Mach Zehnder modulator (PM DMZM) and a polarizer is proposed and demonstrated, which needs no specific large modulation indices or an optical filter. In the proposed method, one sub Mach Zehnder modulator (MZM) in the PM DMZM is driven by a fundamental frequency, which generates an optical signal composed of an optical carrier and a 1st order sideband along one polarization direction; and the other sub MZM is driven by a frequency tripled signal, generating an optical carrier and a 1st order sideband along the orthogonal polarization direction. By adjusting the polarization direction of the polarizer following the PM DMZM, which changes the power ratio of the two sidebands, optical intensity with expression corresponding to the Fourier expansion of a triangular shaped waveform is obtained. Different from the previously reported approaches, neither specific large modulation index nor optical filtering is required, which guarantees a large operational frequency range and improved robustness. A proof of concept experiment is carried out. 5 GHz triangular shaped waveform signals are successfully generated with different modulation indices.

title: Photonic microwave downconverter based on an optoelectronic oscillator using a single dual drive Mach Zehnder modulator.
abstract: A novel and compact photonic microwave downconverter is proposed and experimentally demonstrated based on an optoelectronic oscillator (OEO) using a single dual drive Mach Zehnder modulator (DMZM) The DMZM is used to simultaneously convert the input RF signal into an optical signal, form an OEO for RF carrier extraction, and downconvert the optical RF signal to the baseband. In the experiment, a 2 Gb/s NRZ coded 10.66 GHz RF signal is successfully downconverted to the baseband. In addition, a microwave receiver for wireless high definition (HD) video transmission is built and verified based on the proposed downconverter. The experiment results confirm that the proposed downconverter has simple configuration, good downconversion performance and very stable operation.

title: Photonic generation of a phase coded microwave signal based on a single dual drive Mach Zehnder modulator.
abstract: A compact scheme for photonic generation of a phase coded microwave signal using a dual drive Mach Zehnder modulator (DMZM) is proposed and experimentally demonstrated. In the proposed scheme, the radio frequency (RF) carrier and the coding signal are sent to the two RF ports of the DMZM, respectively. By properly setting the amplitude of the coding signal and the bias voltage of the DMZM, an exact p phase shift phase coded microwave signal is generated. The proposed scheme has a simple structure since only a single DMZM is required. In addition, good frequency tunability is achieved because no frequency dependent electrical devices or wavelength dependent optical devices are applied. The feasibility of the proposed scheme is verified by experiment. 2 or 2.5 Gb/s phase coded 10 and 20 GHz microwave signals are successfully generated.

title: Photonic generation of background free millimeter wave ultra wideband pulses based on a single dual drive Mach Zehnder modulator.
abstract: We propose a novel photonic approach for generating a background free millimeter wave (MMW) ultra wideband (UWB) signal based on a conventional dual drive Mach Zehnder modulator (DMZM) One arm of the DMZM is driven by a local oscillator (LO) signal. The LO power is optimized to realize optical carrier suppressed modulation. The other arm is fed by a rectangular signal. The MMW UWB pulses are generated by truncating the continuous wave LO signal into a pulsed one in a photodetector (PD) The generated MMW UWB signal is background free by eliminating the baseband frequency components because the optical power launched to the PD keeps constant all the time. The proposed method is theoretically analyzed and experimentally verified. The generated MMW UWB signal centered at a frequency of 26 GHz meets the Federal Communications Commission spectral mask very well.