High-output-power, single-wavelength silicon hybrid laser using precise flip-chip bonding technology

Abstract

An Si/III-V hybrid laser oscillating at a single wavelength was developed for use in a large-scale Si optical I/O chip. The laser had an InP-based reflective semiconductor optical amplifier (SOA) chip integrated with an Si wavelength-selection-mirror chip in a flip-chip configuration. A low coupling loss of 1.55 dB at the Si-SOA interface was accomplished by both mode-field-matching between Si-SOA waveguides and accurately controlling the bonding position. The fabricated Si hybrid laser exhibited a very low threshold current of 9.4 mA, a high output power of 15.0 mW, and a high wall-plug efficiency of 7.6% at 20 °C. Moreover, the device maintained a high output power of >10 mW up to 60°C due to the high thermal conductance between the SOA chip and Si substrate. The short cavity length of the flip-chip bonded laser expanded the longitudinal mode spacing. This resulted in temperature-stable single longitudinal mode lasing and a low RIN level of <-130 dB/Hz.

Hybrid photonic crystal lasers

“…Hybrid integration provides a means to combine the III-V and silicon components. Flipchip bonded versions of these lasers [18] are suitable for integration with our previously demonstrated active and passive PhC components for the realization of more complex power-efficient Si photonic systems…”

“…The development of efficient light emission from silicon has been the subject of a large body of research [1][2][3] but still remains elusive. The practical solution is the heterogeneous integration of III-V component on the silicon based photonic integrated circuits by means of direct wafer bonding [4], or the hybrid integration of III-Vs by means of flip-chip bonding [5]. Electro-optic modulators are then the next key component.…”

Emerging heterogeneous integrated photonic platforms on silicon

“…These approaches are indeed as old as silicon photonics itself [54][55][56][57]. Variations of this approach are fairly established and adopted by the silicon photonic industry, e.g., Luxtera Corporation [33,58], NEC Corporation [59], Toshiba Corporation [60], and Fujitsu Laboratories [61]. Perhaps such more straightforward per-device flip-chip bonding approaches suffice the present low-volume, low-throughput needs of the industry but for future highvolume demanding markets, heterogeneous monolithic integration of III-V wafers and Si wafers, or already processed circuits, is more desirable.…”

Analysing radiative and non-radiative recombination in InAs QDs on Si for integrated laser applications

“…Of the approaches listed above, heterogeneous/monolithic integration of III-V and Si yields the most promising results, with wafer bonded devices demonstrating milliwatt output power and continuous wave operation to above 100 °C [7,8]. However, the yield and reliability of these devices has yet to be demonstrated [9,10].…”