Silicon Substrate For Integration Research Articles

Asymmetric multimode interference isolator based on nonreciprocal phase shift

This paper presents an asymmetric multimode interference-based (MMI) optical isolator, by utilizing the magneto-optical nonreciprocal phase shift (NPS). Equivalent beam propagation method (BPM) simulation of symmetric and asymmetric isolators are performed using configuration of Air/Ce:YIG/SiO2 on silicon substrate for integration. The asymmetric isolator is found to be much more compact in size and efficient in isolation compared with symmetric isolator. Simulation results show that the isolation of asymmetric structure is 23.8dB higher than that of symmetric one. It is mainly because both symmetric mode and anti-symmetric mode are excited in asymmetric structure and hence can interfere destructively. The proposed device may play an important role in the optical communication systems and photonic integrated devices.

Packaging compatible microtransformers on a silicon substrate

Surface micromachining techniques have been utilized to realize microtransformers on a silicon substrate for integration with a multi-chip package, allowing compact integration with chips, complementary metal-oxide-semiconductor (CMOS) circuits, sensors, and other components. Two different microtransformers comprised of two-layer vertically stacked spiral-type copper conductor lines and permalloy magnetic cores have been designed, fabricated, and characterized. Low temperature processes have been chosen for fabricating these microtransformers. The fabricated microtransformers have been tested and compared for finding out better geometries for integrated microtransformers. Electroplated thick permalloy cores and copper coils have been utilized for obtaining better performance characteristics in the intermediate frequency range. The fabricated microtransformers have a turn ratio of 1, coupling coefficient of 0.85, DC resistance of 3.3 /spl Omega/, and gain characteristics of -5 dB, respectively. They are suitable for integrated power converter applications, since these devices have also high current carrying capability (up to 2 A steady DC current).