We demonstrate 3rd order micro-ring filters, 100 GHz-spaced 16 channels and 50 GHz-spaced 32 channels. Fabrication-induced resonant wavelength errors, σ = 0.237 nm, and temperature-dependent wavelength shift, 0.043 nm/°C tolerable to ΔT>10 °C, has been measured on filters based on the fundamental TM mode. The problem of CMOS-compatible photolithography is solved, while maintaining a small radius, R = 9 μm. As some dummy channels are arranged, it is shown that an on-chip optical network for many cores CPU can be constructed by 16 channel ring filters with the currently available technology.

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Two-dimensionally arrayed nanocolumns of InGaAsP/InP were fabricated using double-exposure laser holography and reactive ion etching ͑RIE͒. The size and period of nanocolumns could be controlled accurately from 80 to 150 nm in diameter and 220 to 450 nm in period by changing the incident angle of the laser beam. RIE for a typical time of 30 min using CH 4 /H 2 plasma enhanced the aspect ratio by more than 1.5 with a slight increase of the bottom width of columns. Furthermore, a wet-treatment after RIE showed a large enhancement of photoluminescence intensity, suggesting that the damage was cured effectively on the sidewalls of the nanocolumns.Nanometer-scale structures, such as low-dimensional quantum structures and photonic crystals ͑PCs͒, are of considerable interest due to the predicted improvements in device performance and/or realization of new functions by unprecedented control of light. A PC is a kind of periodic nanostructure comprised of optical atoms such as nanoholes or nanocolumns, which are arranged in a medium with a period of submicrometer order and produce unusual properties such as photonic bandgaps in which the propagation of electromagnetic waves is forbidden and spontaneous emission is inhibited. 1 Because material preparation is much easier with 2D PC than with 3D PC, many experimental studies have been reported on twodimensional ͑2D͒ PC recently. It was also known that the 3D control of light is achievable with an index waveguide in the third dimension, simply by using standard nanoprocessing technologies. 2 Therefore, the fabrication of 2D PCs is a key technology for the integration and miniaturization of photonic components, 3 such as a low threshold laser, 4 a waveguide for sharp bends, 5 and a spot-size converter. 6 These additional degrees of freedom for device design can strongly enhance the functionality of integrated optoelectronics.Among the numerous fabrication methods, electron-beam lithography is conventionally used to form nanometer patterns due to its controllability of the feature size. 7-10 In some applications, a largearea formation of the patterns is essential for the efficient fabrication process and mass production, 11 and it also requires high resolution nanofabrication technology with flexibility such as tailoring the feature size, because the periods of 2D PCs should be on the light wavelength scale of interest. Kitson et al. 12 have proposed the multiple exposure method using an interference of monochromatic laser beam, capable of achieving a high throughput for large area pattern formation. Ohira et al. 11 reported the fabrication of nanocolumns with aspect ratios of less than 1 by using the wet etching method after double-exposure lithography.In this article, we demonstrate that 2D arrays of nanocolumns with variable widths and periods can be fabricated uniformly using laser holography and a dry-etching process. The aspect ratio of the nanocolumns could be increased to more than 1.5 by CH 4 -based RIE. Furthermore, we discuss the etch behavior in the formation of na...

It is shown that the resonant frequencies and the transmission spectra of ring resonators can be adjusted by depositing or etching the cladding nitride layer on the ring waveguide without introducing an extra loss or extra variations of channel spacing. The cladding nitride layer increases the minimum width of the gap in the coupling region to larger than 150nm which makes it possible to consider photolithography instead of E-beam lithography for the typical design rule of ring filters. KOH silicon etching can also adjust not only the resonance frequencies but also coupling coefficients with a small sacrifice of guiding loss.

We present a silicon-on-insulator Echelle grating 8-channel demutiplexer showing characteristic features, average insertion loss 2.4 dB measured at 1520~1570 nm, adjacent channel crosstalk 15-18 dB, and channel spacing 11.9 nm. Our Echelle grating is remarked by a total internal reflector (TIR) which reflects incident light by a single reflection in contrast to the double reflections of retro-reflector TIR Echelle gratings.