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Hitoshi NAKAMURA Masato SHISHIKURA Shigehisa TANAKA Yasunobu MATSUOKA Tsunao ONO Takao MIYAZAKI Shinji TSUJI
We propose an InGaAlAs waveguide p-i-n photodiode (WG-PD) with a thick symmetric double-core for surface-hybrid integration onto optical platforms, which can be applied to low cost optical modules for access networks. The waveguide structure is designed to efficiently couple to flat-ended single mode fibers while maintaining low-voltage (less than 2 V) operation. Crystal growth conditions and a passivation technique are also investigated for obtaining high responsivity, low dark current and highly reliable operation. Fiber-coupled responsivity as high as 0.95 A/W, at a 1.3-µm wavelength, and vertical coupling tolerance as wide as 2.6 µm are demonstrated for a dispersion-shifted fiber (DSF) coupling at an operating voltage of 2 V. Dark current is as low as 300 pA at 25 and 12 nA at 100. A temperature accelerated aging test is performed to show the feasibility of using the WG-PD in long-term practical applications.
Yoshimasa SUGIMOTO Yu TANAKA Naoki IKEDA Kyozo KANAMOTO Yusui NAKAMURA Shunsuke OHKOUCHI Hitoshi NAKAMURA Kuon INOUE Hidekazu SASAKI Yoshinori WATANABE Koji ISHIDA Hiroshi ISHIKAWA Kiyoshi ASAKAWA
We have fabricated several two-dimensional photonic-crystal (2DPC) slab waveguides by using fine electron beam lithography and dry etching. The 2DPC waveguides include straight, bend, Y-branch, directional coupler, and coupled-cavity waveguides on the GaAs/AlGaAs substrate as an application to the ultra-small and ultra-fast all-optical switching device. Transmission spectra and near field patterns were characterized in a wide wavelength range from 850 to 1600 nm with the sample finished to the air-bridge type 2DPC slab. These waveguides appear to be suitable for achieving the waveguide platform in the symmetrical-Mach-Zehnder device.