Ms. Takei, a 1st year master's student, presented a paper at CLEO Pacific Rim 2020.

CLEO PR 2020 (Conference on Lasers and Electro-Optics Pacific Rim), the international conference on laser and electro-optics, was held from August 3 to 5, 2020. CLEO PR 2020 was scheduled to be held in Sydney, Australia, but due to the spread of new coronavirus infection, the entire program was held in a virtual format.
Ms. Takei, a 1st year master's student, submitted a research paper and it was accepted as an oral presentation paper at this conference.
In the paper, Mr. Takei presented the research results of further development on the measurement method applying the coherent heterodyne technology and digital signal processing technology to the backscattered light measurement method of optical fibers, which was announced at CLEO 2020 in May.
This paper describes the results of high-resolution measurement of the distribution of optical fiber birefringence in the longitudinal direction of the fibers. The distribution of optical fiber birefringence has been measured so far, but since the polarization OTDR (POTDR) method was used, the measurement time was at least several tens of seconds. By using the technique proposed in this paper, the phase of backscattered light can be directly measured, so the measurement time excluding the signal processing time can be reduced to only about 1 ms. This paper also describes the measurement results of the probability distribution of birefringence in single-mode optical fibers using this technology.
We plan to further develop this technology and consider various applications.

Presented paper
N. Takei and S. Ryu, "Rapid measurement of spatial distribution of birefringence in optical fibers by coherent heterodyne detection of Rayleigh backscattered light," CLEO Pacific Rim 2020, Concurrent 10F, August 2020.