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Shinji YAMASHITA Teruyuki BABA Yoshinori NAMIHIRA
We propose and demonstrate a novel method to measure the polarization mode dispersion (PMD) of optical devices. The device under test (DUT) is installed in a fiber laser cavity which can operate at multiwavelength. PMD can be evaluated by the wavelength spacing of the multiwavelength laser output spectrum. In our method, the maximum extrema wavelength is easier to be identified than in the conventional fixed-analyzer (FA) method. We measure the PMD of polarization maintaining fibers (PMFs) and the ITU-T round robin KDD samples.
Takuya TANAKA Hiroshi TAKAHASHI Yoshinori HIBINO Toshikazu HASHIMOTO Akira HIMENO Yasufumi YAMADA Yuichi TOHMORI
We describe the fabrication method and characteristics of hybrid external cavity lasers composed of a spot-size converter integrated LD (SS-LD) and a UV written Bragg grating in a planar lightwave circuit (PLC) on a Si substrate. The SS-LD is passively aligned on a Si platform formed in the PLC, and the UV grating is created in the PLC with ArF laser irradiation through a phase mask. This structure enables us to fabricate a stable single-mode laser with a precisely controllable oscillation wavelength. By using the above techniques, we obtained a threshold current of 7-8 mA and a side mode suppression of 37 dB for an external cavity laser operating at 1.3 µm. Moreover, we successfully demonstrated a four-channel external cavity laser with a wavelength interval of 2 nm 0.1 nm by integrating 4 SS-LDs on a PLC and controlling the Bragg wavelengths with ArF laser irradiation without a phase mask.