Van D Thourhout

Laser emission and photodetection in an InP/InGaAsP layer integrated on and coupled to a Silicon-on-Insulator waveguide circuit

Laser emission from an InP/InGaAsP thin film epitaxial layer bonded to a Silicon-on-Insulator waveguide circuit was observed. Adhesive bonding using divinyl-tetramethyldisiloxane-benzocyclobutene (DVS-BCB) was used to integrate the InP/InGaAsP epitaxial layers onto the waveguide circuit. Light is coupled from the laser diode into an underlying waveguide using an adiabatic inverted taper approach. 0.9mW optical power was coupled into the SOI waveguide using a 500mum long laser. Besides for use as a laser diode, the same type of devices can be used as a photodetector. 50mum long devices obtained a responsivity of 0.23A/W.

Adhesive bonding of InP/InGaAsP dies to processed silicon-on-insulator wafers using DVS-bis-benzocyclobutene

The process of bonding InP/InGaAsP dies to a processed silicon-on-insulator wafer using sub-300 nm layers of DVS-bis-benzocyclobutene (BCB) was developed. The planarization properties of these DVS-bis-BCB layers were measured and an optimal prebonding die preparation and polymer precure are presented. Bonding quality and bonding strength are assessed, showing high-quality bonding with sufficient bonding strength to survive postbonding processing.

Ultra thin DVS-BCB adhesive bonding of III-V wafers dies and multiple dies to a patterned silicon-on-insulator substrate

Heterogeneous integration of III-V semiconductor materials on a silicon-on-insulator (SOI) platform has recently emerged as one of the most promising methods for the fabrication of active photonic devices in silicon photonics. For this integration, it is essential to have a reliable and robust bonding procedure, which also provides a uniform and ultra-thin bonding layer for an effective optical coupling between III-V active layers and SOI waveguides. A new process for bonding of III-V dies to processed silicon-on-insulator waveguide circuits using divinylsiloxane-bis-benzocyclobutene (DVS-BCB) was developed using a commercial wafer bonder. This “cold bonding” method significantly simplifies the bonding preparation for machine-based bonding both for die and wafer-scale bonding. High-quality bonding, with ultra-thin bonding layers (<50 nm) is demonstrated, which is suitable for the fabrication of heterogeneously integrated photonic devices, specifically hybrid III-V/Si lasers.

Integration of InP/InGaAsP photodetectors onto silicon-on-insulator waveguide circuits

The integration of optical functionalities on a chip has been a long standing goal in the optical community. Given the call for more integration, Silicon-on-Insulator (SOI) is a material system of great interest. Although mature CMOS technology can be used for the fabrication of passive optical functionality, particular photonic functions like efficient light emission still require III-V semiconductors. We present the technology for heterogeneous integration of III-V semiconductor optical components and SOI passive optical components using benzocyclobutene (BCB) die to wafer bonding. InP/InGaAsP photodetectors on SOI waveguide circuits were fabricated. The developed process is compatible with the fabrication of InP/InGaAsP light emitters on SOI.

Unidirectional III-V microdisk lasers heterogeneously integrated on SOI

We demonstrate unidirectional bistability in microdisk lasers electrically pumped and heterogeneously integrated on SOI. The lasers operate in continuous wave regime at room temperature and are single mode. Integrating a passive distributed Bragg reflector (DBR) on the waveguide to which the microdisk is coupled feeds laser emission back into the laser cavity. This introduces an extra unidirectional gain and results in unidirectional emission of the laser, as demonstrated in simulations as well as in experiment.

Bias-free, low power and optically driven membrane InP switch on SOI for remotely configurable photonic packet switches

A small footprint integrated Membrane InP Switch (MIPS) on Silicon-On-Insulator (SOI) is demonstrated for use in all-optical packet switching. The device consists of an optically pumped III-V membrane waveguide of only 100 nm thick, coupled to the underlying SOI waveguide circuit. Because of its limited thickness, the optical confinement in the active layers is maximized, allowing for high extinction ratio of over 30 dB when applying a low power optical pump signal, over the entire C-band. The switch has 400/1300 ps on/off switching times and no measurable pattern dependence or switching related power penalties for a bitrate up to 40 Gb/s, using a switching power of only 2 dBm.

InP/InGaAs photodetector on SOI circuitry

We present the design, fabrication and characterization of an InP-based membrane photodetector on an SOI wafer containing a Si-wiring photonic circuit. Measured detector responsivity and 3 dB bandwidth are 0.45 A/W and 33 GHz, respectively. The photonic device fabrication is compatible with wafer scale processing steps, guaranteeing compatibility towards future generation electronic IC processing.

Light emission and enhanced nonlinearity in nanophotonic waveguide circuits by III–V/silicon-on-insulator heterogeneous integration

The heterogeneous integration of a III–V thin film on top of a silicon-on-insulator (SOI) optical waveguide circuit by means of adhesive divinylsiloxane-benzocyclobutene (DVS-BCB) die-to-wafer bonding is demonstrated, thereby achieving light emission and enhanced nonlinearity in ultracompact SOI cavities. This approach requires ultrathin DVS-BCB bonding layers to allow the highly confined optical mode to overlap with the bonded III–V film. The transfer of sub-100-nm III–V layers using a 65 nm DVS-BCB bonding layer onto SOI racetrack resonator structures is demonstrated. Spontaneous emission coupled to a SOI bus waveguide, spectrally centered around the resonator resonances, is observed by optically pumping the III–V layer. Strong carrier-induced nonlinearities are observed in the transmission characteristics of the III–V/SOI resonator structure. The all-optical control of an optical signal in these III–V/SOI resonators is demonstrated.

InP-based Membrane Photodetectors for Optical Interconnects to Si

We present the design, fabrication and a characterization of an InP-based membrane photodetector on an SOI wafer containing a Si-wiring photonic circuit. Waveguide losses in the Si-wiring circuit are below 5 dB/cm. Measured detector responsivity is 0.45 A/W. The photonic device fabrication is compatible with wafer scale processing steps, guaranteeing compatibility towards future generation electronic IC processing.

Indium phosphide based membrane photodetector for optical interconnects on silicon

We have designed, fabricated and characterized an InP-based membrane photodetector on an SOI wafer containing a Si-wiring photonic circuit. New results on RF characterization up to 20 GHz are presented. The detector fabrication is compatible with wafer scale processing steps, guaranteeing compatibility towards future generation electronic IC processing.