抄録
We propose a simple method for measuring the birefringence of a polarization maintaining fiber (PMF).
Our method is based on measurements of the spontaneous emission noise intensity variation in a gainswitched
distributed feedback semiconductor laser with delayed optical feedback. The optical lengths of
the PMF along both the fast and slow axes were measured separately with a resolution of 20 μm. From
the measured optical lengths, the ratio of the birefringence to the refractive index of the fast axis was
estimated to be (2.217 ± 0.012) × 10‒4. We checked the validity of the estimated value by comparing it
with the measured value of (2.2452 ± 0.0002) × 10‒4 in a conventional method using a Sagnac
interferometer.
