We demonstrate the integration of a single-crystal magneto-optical film onto thin silicon-on-insulator (SOI) waveguides by use of direct wafer bonding. Simulations show that the high confinement and asymmetric structure of SOI allows an enhancement of approximately 3x over the nonreciprocal phase shift achieved in previous designs; this value is confirmed by our measurements. Our structure will allow compact magneto-optical nonreciprocal devices, such as isolators, integrated on a silicon waveguiding platform.

Abstract:We report the design criteria and performance of Si ring resonators for passive athermal applications in wavelength division multiplexing (WDM). The waveguide design rules address i) positivenegative thermo-optic (TO) composite structures, ii) resonant wavelength dependent geometry to achieve constant confinement factor ( Γ ), and iii) observation of small residual second order effects. We develop exact design requirements for a temperature dependent resonant wavelength shift (TDWS) of 0 pm/K and present prototype TDWS performance of 0.5pm/K. We evaluate the materials selection tradeoffs between high-index contrast (HIC) and low-index contrast (LIC) systems and show, remarkably, that FSR and footprint become comparable under the constraint of athermal design.

Bonding between liquid-phase-epitaxy-grown yttrium iron garnet films and various semiconductors is realized by direct wafer bonding. The semiconductor substrates can serve as a platform for integration or as a “handle” platform for the transfer of mesoscopic garnet films. To effect film transfer, a sacrificial layer is formed in the garnet by deep ion implantation prior to bonding. Shear stress at the garnet/semiconductor interface can be controlled by temperature tuning during the bonding process. A debonding temperature threshold of ∼400 °C is found and related to the interfacial thermal stress due to difference in thermal expansion coefficients of the bonded materials. Film separation is realized by the application of thermally induced stress at the sacrificial layer.

We review the main ROADM subsystem technologies, and propose a 40-channel PLCbased ROADM subsystem that exhibits ultra-low power consumption and compact size, while meeting the requirements for high optical performance, high reliability, and low cost.