Low-Threshold Heterogeneously Integrated InP/SOI Lasers With a Double Adiabatic Taper Coupler

Abstract

Abstract-We report on a heterogeneously integrated InP/SOI laser source realized through DVS-BCB wafer bonding. The hybrid lasers present several new features. The III-V laser is only 1.7μm wide, reducing the power consumption of the device. The silicon waveguide thickness is 400 nm, compatible with highperformance modulator designs and allowing efficient coupling to a standard 220nm high index contrast silicon waveguide layer. In order to make the mode coupling efficient, both the III-V waveguide and silicon waveguide are tapered, with a tip width for the III-V waveguide of around 800 nm. These new features lead to good laser performance: a lasing threshold as low as 30mA and an output power of more than 4mW at room temperature in continous wave operation regime. Continuous wave lasing up to 70C is obtained.Index Terms-Hybrid integrated circuits, silicon laser, silicon-on-insulator (SOI) technology, adiabatic taper.

Optimization of taper structures for III-V on Silicon lasers

“…At the ends of the gain section, light is coupled to the silicon waveguide layers using an adiabatic taper. Initial results showed Fabry-Perot type devices operating with threshold currents as low as 30mA and output powers up to 4mW [6]. Here we present a study focusing on the adiabatic taper and show how its design influences the operation of the device.…”

“…Therefore an alternative approach based on bonding high quality epi-layers on prepatterned silicon waveguide structures has been developed by several groups . We recently proposed a new structure [6] whereby light in the gain section is maximally confined in the III-V quantum well layers. At the ends of the gain section, light is coupled to the silicon waveguide layers using an adiabatic taper.…”

“…Figure 1 shows a top view, longitudinal and transversal cross-sections of the proposed device. Its fabrication and operation was described in [6]. InP-wafers containing the active layers were bonded on prefabricated silicon waveguides with 400nm height.…”

Substrate bonding using electroplated copper through silicon vias for VCSEL fabrication

“…It enables to benefit on the same chip electronics, lasers, modulators, and waveguides, with the use of adhesive polymer bonding [1] or a Vand der Waals bonding [2]. Also, to improve device performances, III-V components are commonly bonded on host substrates presenting a high thermal resistivity.…”

Hybrid III–V/Si Distributed-Feedback Laser Based on Adhesive Bonding

“…In recent years, DVS-BCB bonding has been successfully used for the fabrication of hybrid III-V/Si lasers with adiabatic polymer-overlayed inverted tapers [6], narrow-tip spot-size converters [7], as well as microdisk lasers [8]. The adhesive bonding layers in these applications were not always thin enough to be suitable for evanescent hybrid lasers.…”