Influence of exterior acoustic noise on narrow linewidth laser measurements using self-homodyne optical fiber interferometer

Optical Fiber Spool Acoustic Wave Resonances Employing a Mach-Zehnder Interferometer in Vacuum Chamber

“…Additionally, the PSD intensity level of the measured resonances are shown in the last column of [30]. Indeed, the FFT frequency span shall be less than the laser linewidth of 220 Hz to achieve the best SNR using the MZI configuration of Fig.…”

“…Theory [35] and results [30] using commercial Finite Element Analysis packets: NASTRAN [42] and COMSOL [47].…”

“…The Finite Element COMSOL results of Table II assume were used to estimate the fiber induced birefringence [30] and smaller resonance frequencies in relation to the experiment were obtained. This might be a consequence of the Finite Element mesh constraints due to limitations of the computer memory and speed.…”

“…Nevertheless, the resonance effects of the OFS detector may also generate false positive signals in those applications. Additionally, OFS-MZI based self-homodyne (or self-heterodyne) linewidth measurements can be influenced by acoustical induced optical noises [30]. As a result, the…”

“…Those applications require the evaluation of the laser parameters such as Lorentzian linewidth [20]- [21], and several techniques have been developed for linewidth measurements [22], comprising: delayed selfheterodyne [23]- [24]; self-homodyne detection with short delay Mach-Zehnder interferometer (MZI) [25]; Brillouin induced self-heterodyne [26]; strong coherent envelope [27]; and heterodyne offline digital signal processing [28]- [29]. The use of the self-homodyne fiber MZI has the advantage of using only one laser with no distinct local oscillator, and the authors employed this technique to analyze narrow linewidth lasers [30].…”