| Budget Amount *help |
¥8,600,000 (Direct Cost: ¥8,600,000)
Fiscal Year 1989: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1988: ¥7,600,000 (Direct Cost: ¥7,600,000)
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| Research Abstract |
ARROW is a novel single-mode optical waveguide on a semiconductor substrate which utilizes a pair of thin interference cladding layers between the core and substrate. This waveguide is promising for integrated optics because of many features. e.g. (1)low loss. (2)ease of fabrication owing to thin cladding and luck of necessity to control the refractive indexes precisely, (3)performance of useful functions, such as polarization and wavelength selective characteristics, and so on. In this study, by utilizing the last feature, the investigator have aimed at developing a novel integrated device of ARROW-type demultiloexer and photodetector on a silicon substrate.
In the study of last fiscal year, an ARROW-type demultiplexer operating at the wavelengths of 0.78 mum and 0.88 mum was designed, and it was shown that an isolation as high as 20 dB is achievable. Next the integrated device of ARRONY-type demultiplexer and photodetector was fabricated and its fundamental function was confirmed. In
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the current fiscal year. the demultiplexing characteristics of the integrated device was measured precisely and a clear demultiplexing characteristics having a center wavelength of 0.83 mum was observed. In addition to this. we invented a modified structure of ARROW named ARROW-B. which can overcome the polarization dependence of propagation loss in ARROW, and a new three dimensional structure of ARROW named STRIPE LATERAL CONFINESIENT OF ARROW. which can be fabricated easily by etching only a thin intermediate layer. On the other hand. we investigated the scattering loss of ARROW to reduce the propagation loss, and showed that the discrepancy between the measured and theoretical values of propagation loss ia attributed to the scattering loss resulting from the surface roughness. By optimizing the fabrication process, the propagation loss of ARROW was successfully reduced to 0.16 db/cm, which is the lowest record of ARROW.
The investigator is planning to continue this study by utilizing many features of ARROW, e.g. high density optical interconnection by stacking ARROWs. Less
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