Photonic-Assisted Wideband Phase Noise Analyzer Based on Optoelectronic Hybrid Units

Abstract

We demonstrate a photonic-assisted wideband phase noise analyzer based on optoelectronic hybrid units comprising a microwave photonic phase shifter (MPS) and a microwave true time delayer. The MPS and the microwave true time delayer are achieved by a dual-drive Mach-Zehnder modulator (DMZM) incorporating with a broadband microwave frequency up-convertor (MFC) and an optical fiber delay line (ODL), respectively. Our scheme, which is analogous to the conventional microwave delayed homodyne self-reference method, can effectively improve its accuracy using longer time delay with minimum power consumption. In the scheme, the microwave signal is up-converted using the MFC and then down-converted using optical mixing in a photo-detector (PD). Meanwhile, the microwave signal is phase shifted using the MPS and time delayed using the ODL and are finally homodyne mixed with reference signals for converting phase fluctuations to voltage fluctuations. The motivation of this work lies in the fact that the previously reported phase noise measurement configurations based on photonic techniques are hard to accurately measure phase noise of microwave oscillators working at low frequencies. The microwave signals are phase tuned over 360º at frequency range of 0.5-9 GHz to achieve a photonic-assisted phase detector. Microwave signals at the frequency of 3-, 9-GHz are measured with a phase noise of -70.9 and -66 dBc/Hz at 1 kHz offset frequency, respectively.Index Terms-Phase noise measurement, microwave photonic phase shifter, microwave frequency up-conversion.

High Precision Phase Noise Analysis Based on a Photonic-Assisted Microwave Phase Shifter Without Nonlinear Phase Distortion

“…However, the system based on a polarization modulator is extremely sensitive to the surrounding environment, making it unreliable for realistic applications [22], [23]. In another study [18], a dual-drive Mach-Zehnder modulator was utilized to upconvert the low-frequency signal to a higher frequency. This approach effectively expanded the operational bandwidth of the system at lower frequencies to 0.5 GHz.…”

Wideband microwave phase noise measurement based on photonic-assisted I/Q mixing and digital phase demodulation

“…Photonic-delay-line-based phase noise measurement, which acquires the phase noise by mixing the signal under test (SUT) with its optically delayed replica, attracts great attentions thanks to its high phase noise measurement sensitivity [4][5][6][7]. To measure the phase noise of signals in a large frequency range, the bandwidth limitation of electrical phase shifters and frequency mixers should be overcome, which can be solved by implementing microwave phase shifting and frequency mixing in the optical domain [8][9][10][11]. However, a feedback loop is required in these systems to ensure that the SUT and its delayed copy are quadrature to each other before sent to a frequency mixer, which is usually implemented by dynamically controlling an adjustable electrical or microwave photonic phase shifter incorporated in the feedback loop.…”

Wideband Microwave Phase Noise Analyzer Based on All-Optical Microwave Signal Processing

“…However, among the previously reported photonic-delay-line-based phase noise measurement systems, the operational bandwidth is usually restricted by electrical devices (e.g., electrical mixers, phase shifters and amplifiers). To cope with this problem, the functions of microwave phase shifting [21,22] or frequency mixing [23] are realized based on microwave photonic technologies to achieve bandwidth enhancement. Nevertheless, an all-optical phase noise measurement system that realizes all microwave signal processing functions in the optical domain, has rarely been reported [24].…”