Use of Fiber Optic Link for Phase-Noise Measurement

The measurement of phase noise plays a critical role in the characterization of modern radio and optical systems. This paper explores the use of fiber optic links to quantify phase noise. It introduces the delay-line method for measuring phase noise and explains its advantages and limitations. It presents the photonic-delay phase-noise measurement method and its implementation using standard components in fiber-optic access network equipment. The importance of achieving quadrature locking in the mixer for accurate phase noise measurement is highlighted, along with the calibration process. The paper concludes with an example of phase noise characteristics in an opto-electronic oscillator.