Compact Integration of Optical Sources and Detectors on SOI for Optical Interconnects Fabricated in a 200 mm CMOS Pilot Line

Abstract

Abstract-As the demand for bandwidth increases, optical interconnects are coming closer and closer to the chip. Optical interconnects on silicon-on-insulator (SOI) are desirable as this allows for integration with CMOS and the mature processing can be used for photonic integrated circuits. A heterogeneous integration process can be used to include III-V active optical components on SOI. For dense integration compact sources and detectors are required, but they typically need different epitaxial structures to be efficient which limits the integration density. We propose to use an epitaxial structure, which contains both the layers for a laser and for a detector, hereby enabling very compact integration of sources and detectors. Microdisk lasers and waveguide detectors using this epi were completely fabricated in a 200 mm CMOS pilot line and the results are discussed here.Index Terms-Heterogeneous integration, microdisk laser (MDL), optical interconnect, photonic integration, silicon-oninsulator (SOI), waveguide detector.

Realization of a Compact Optical Interconnect on Silicon by Heterogeneous Integration of III–V

“…by an external reflector as suggested above, the link efficiency could increase to 6%. It is also interesting to note that the LI curve of the microdisk laser is much smoother compared to results published earlier [5] where the output of the microdisk was collected via a grating coupler. It was suggested that the oscillations in the LI curve were attributed to reflections from the grating coupler.…”

“…It consists of a 580 nm thin layer stack for the laser containing 3 compressively strained quantum wells and on top of this laser stack there is a 500 nm InGaAs based stack for the detector. Detailed information about this epitaxial structure can be found in [5]. As a single epitaxial structure is used, it becomes possible to make efficient lasers and detectors right next to each other and thus form an optical transceiver.…”

“…Although silicon is not suited as a light emitter or detector in the infrared, several approaches have been demonstrated to integrate lasers and detectors on a silicon platform [2][3][4][5] modulators and detectors, is an important requirement. This can be achieved by using e.g.…”

“…Recently we demonstrated a CMOS compatible approach that enables compact integration of microdisk lasers and photodetectors, by using a single III-V epitaxial structure bonded on silicon [5]. All fabrication steps for the laser and detector, except for the detector mesa, are carried out simultaneously.…”

Unidirectional III-V microdisk lasers heterogeneously integrated on SOI

“…In [20], the LI curves of a microdisk laser at elevated temperatures remain smooth and unidirectional under pulsed driving conditions, in contrast to the case where continuous wave drive conditions were applied. Most likely this is because when the ambient temperature is changed, it affects both the silicon waveguide and the InP-based microdisk cavity, while the self heating effect in continuous wave mode only heats up the disk cavity.…”