High-frequency characterization of an optical phase modulator with phase modulation-to-intensity modulation conversion in dispersive fibers

Abstract

We propose a new method for characterizing optical phase modulators based on phase modulation-to-intensity modulation (PM-to-IM) conversion in dispersive fibers. The fiber dispersion spectrally alters the relative phasing of the phase-modulated signal and leads to the PM-to-IM conversion, which is extended to measure the modulation efficiency of optical phase modulators. In the demonstration, the frequency-dependent modulation index and half-wave voltage are experimentally measured for a commercial phase modulator. Compared with conventional methods, the proposed method works without the restriction of small-signal operations, and allows swept-frequency measurement with high resolution and accuracy by using a vector network analyzer. electro-optic modulators, microwave photonics, optical fiber dispersion, phase modulation Citation:Zhang S J, Lu R G, Chen D J, et al. High-frequency characterization of an optical phase modulator with phase modulation-to-intensity modulation conversion in dispersive fibers.

Dispersive optical systems for scalable Raman driving of hyperfine qubits

“…where α = Gω 2 q /2 describes the phase curvature as a function of sideband index. The resulting Raman Rabi frequency depends simply on the phase-modulation depth β and the dispersion curvature α according to a Bessel function identity (F5) [28]:…”

“…However, in practice, the electro-optic phase-modulation depth is limited to β π , requiring α π/4 to achieve reasonable efficiency; this corresponds to an enormous dispersion of G 8.5 × 10 8 fs 2 . For comparison, dispersion in a typical optical fiber is approximately 4 × 10 4 fs 2 /m [28,29]. Even ultrahighdispersion chirped Bragg mirrors (mirrors with gradually varying Bragg layer thickness) offer only up to 1300 fs 2 from a single reflection [30] [see Fig.…”