Figure 10.

Comparison of the measured and calculated S/N along a 5 m long polarization-maintaining (PM) fiber, where the up-conversion frequency was 10.881 GHz and the DFB LD was driven with current source B whose power spectral density is shown in Figure 5b. Both ends of the PM fiber were spliced to 250 µm buffered single-mode fibers with APC connectors which were mated to those of the fiber pigtails of optical circulators CL1 and CL2. z_c (= 3.8 m) is the distance to the center of pumping. The fast and slow axes of the PM fiber were excited by the respective probe light and counter-propagating pump lights by using in-line polarization controllers (PCs). CL1 and CL2 are optical circulators. ω_p and ω_p + Ω are the angular frequencies of the counter-propagating pump light waves. APC: Angled physical contact.