Micro-transfer printing InP C-band SOAs on advanced silicon photonics platform for lossless MZI switch fabrics and high-speed integrated transmitters.

We present an approach for the heterogeneous integration of InP semiconductor optical amplifiers (SOAs) and lasers on an advanced silicon photonics (SiPh) platform by using micro-transfer-printing (µTP). After the introduction of the µTP concept, the focus of this paper shifts to the demonstration of two C-band III-V/Si photonic integrated circuits (PICs) that are important in data-communication networks: an optical switch and a high-speed optical transmitter. First, a C-band lossless and high-speed Si Mach-Zehnder interferometer (MZI) switch is demonstrated by co-integrating a set of InP SOAs with the Si MZI switch. The micro-transfer-printed SOAs provide 10 dB small-signal gain around 1560 nm with a 3 dB bandwidth of 30 nm. Secondly, an integrated transmitter combining an on-chip widely tunable laser and a doped-Si Mach-Zehnder modulator (MZM) is demonstrated. The laser has a continuous tuning range over 40 nm and the transmitter is capable of 40 Gbps non-return-to-zero (NRZ) back-to-back transmission at wavelengths ranging from 1539 to 1573 nm. These demonstrations pave the way for the realization of complex and fully integrated photonic systems-on-chip with integrated III-V-on-Si components, and this technique is transferable to other material films and devices that can be released from their native substrate.

Micro-transfer-printed III-V-on-silicon C-band distributed feedback lasers.

We report on single-mode C-band distributed feedback lasers fabricated through micro-transfer-printing of semiconductor optical amplifier coupons fabricated on a InP source wafer onto a silicon-on-insulator photonic circuit. The coupons are micro-transfer printed on quarter-wave shifted gratings defined in SiN deposited on the silicon waveguide. Alignment-tolerant adiabatic tapers are used to efficiently couple light from the hybrid III-V/Si waveguide to the Si waveguide circuit. 80 mA threshold current and a maximum single-sided waveguide-coupled output power above 6.9 mW is obtained at 20 °C. Single mode operation around 1558 nm with > 33 dB side mode suppression ratio is demonstrated. Micro-transfer printing-based heterogeneous integration is promising for the wafer-level integration of advanced laser sources on complex silicon photonic integrated circuit platforms without changing the foundry process flow.

Transfer-printing-based integration of a III-V-on-silicon distributed feedback laser.

An electrically pumped DFB laser integrated on and coupled to a silicon waveguide circuit is demonstrated by transfer printing a 40 × 970 µm2 III-V coupon, defined on a III-V epitaxial wafer. A second-order grating defined in the silicon device layer with a period of 477 nm and a duty cycle of 75% was used for realizing single mode emission, while an adiabatic taper structure is used for coupling to the silicon waveguide layer. 18 mA threshold current and a maximum single-sided waveguide-coupled output power above 2 mW is obtained at 20°C. Single mode operation around 1550 nm with > 40 dB side mode suppression ratio (SMSR) is realized. This new integration approach allows for the very efficient use of the III-V material and the massively parallel integration of these coupons on a silicon photonic integrated circuit wafer. It also allows for the intimate integration of III-V opto-electronic components based on different epitaxial layer structures.