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ELOS 2021

Masahiko Kondow

Masahiko Kondow, Speaker at Masahiko Kondow: Speaker for Optics Conference
Osaka University, Japan
Title : Circular defect in photonic crystal (CirD) laser for intra-chip optical interconnects


By the analogy of inter-chip optical interconnects, the target density for intra-chip optical interconnects is estimated to be 10 Pbps/cm2. This value may not be possible anymore by so called Si-photonics that is the state-of-the-art technology, because its target density is as small as 10 Tbps/cm2. The authors have proposed a breakthrough by using 2 dimensional photonic crystal (2D-PhC). The laser has a circular defect (CirD) cavity in the triangular PhC lattice. Compact optical modules with a wavelength division multiplexing (WDM) function can be constructed by integrating several CirD lasers with one PhC line-defect waveguide for light output without a conventional optical multiplexer that have huge footprint in comparison with CirD lasers. In the numerical analysis, uniform low threshold and a modulation speed of approximately 50 Gbps within a lasing wavelength range of 20 nm can be estimated for the CirD lasers, because quality factors (Q) of CirD lasers are expected to be several thousands. In addition, single-mode lasing operations of CirD lasers with a linewidth narrower than 0.07 nm and the side-mode suppression-ratio (SMSR) of approximately 30 dB have been experimentally confirmed by conducting optical pumping under room-temperature continuous-wave (RT-CW) conditions. The lasing wavelengths of CirD lasers can be modulated over 20 nm. Thus, the bandwidth capacity of 1 Tbps may be realized by 20 channels of WDM within footprint of approximately 100 mm squire that equals 1 × 10-4 cm2. This meets the extremely high bandwidth density requirement of 10 Pbps/cm2 for intra-chip optical interconnects.


Dr. Masahiko Kondow received the B.E. and M.E. degrees in electrical engineering, from Osaka University in 1984 and 1986, respectively.  Since 1986, he had been with Central Research Laboratory, Hitachi, Ltd.  He received the Ph.D. degree in electrical engineering, from Osaka University in 1991.  In 1998, he was with University of California, San Diego, as a visiting scholar.  Since 2005, he has been with Osaka University as a professor in Graduate School of Engineering.