Heterogeneously integrated III-V/silicon distributed feedback lasers

Abstract

Received Month X, XXXX; revised Month X, XXXX; accepted Month X, XXXX; posted Month X, XXXX (Doc. ID XXXXX); published Month X, XXXX Heterogeneously integrated III-V-on-silicon second order distributed feedback lasers utilizing an ultra-thin DVS-BCB die-to-wafer bonding process are reported. A novel design exploiting high confinement in the active waveguide is demonstrated. 14mW output power coupled to a silicon waveguide, 50dB side mode suppression ratio and continuous wave operation up to 60°C is obtained. Silicon photonics is emerging as an important platform for the realization of high-speed optical transceivers. This is related to the fact that the silicon waveguide circuits, comprising ultra-compact passive waveguide circuitry, high-speed optical modulators and germanium photodetectors, can be fabricated using complementary metal-oxide-semiconductor (CMOS) fabrication technology in large volumes and at low cost [1]. However, the integration of a coherent light source on the silicon platform remains an issue. While electrically driven germanium laser sources have been demonstrated [2], the performance of these devices is still far inferior to what can be achieved using InP-based III-V semiconductors. III-V semiconductor layer stacks can be heterogeneously integrated onto the silicon waveguide circuit using a wafer bonding technique followed by InP substrate removal, which provides a route towards wafer-scale processing of these III-V epitaxial layers, lithographically aligned to the underlying waveguide circuit. In recent years, several device demonstrations were made on this III-V/silicon platform [3], both using a molecular [4] and adhesive bonding approach [5]. In this paper we describe the realization of single wavelength 1550nm distributed feedback (DFB) lasers coupled to a 220nm thick silicon waveguide layer, with waveguide coupled output powers of 14mW, a side-mode-suppression ratio better than 50 dB and a laser linewidth of 1MHz. The coupling to a 220nm silicon waveguide circuit will allow in a later stage to cointegrate high speed devices such as modulators and photodetectors with the single wavelength lasers using the available silicon photonics platform technology as offered by several multi-project wafer run services worldwide.The distributed feedback laser structures reported in this paper are based on quarter-wave shifted second order gratings with a Bragg wavelength around 1550nm. The three dimensional layout of the laser cavity is depicted in Figure 1(a), while a longitudinal cross-section of the laser geometry is shown in Figure 1(b). The gratings are

Demonstration of self-pulsating InP-on-Si DFB laser diodes

“…The quantum well layer is wider than the mesa to reduce surface recombination. The fabrication process is comprehensively explained in [13][14].…”

III-V-on-Silicon Photonic Devices for Optical Communication and Sensing

“…This means that no power exchange occurs between the fundamental waveguide mode and the higher order waveguide modes. In many of our recently developed laser devices, a double adiabatic tapered coupler has been successfully implemented [7][8][9]. For use in electro-absorption modulator (EAM) devices, a very compact tri-sectional tapered coupler has recently been proposed [10].…”

“…The device geometry of the double adiabatic tapered coupler is shown in Figure 3a [9]. The coupler is piecewise linear and consists of two parts: the first part (Taper I) has a length of 35 μm and decreases the III-V waveguide width from 3 μm to 1 μm.…”

“…Typically, the used adiabatic taper structures allow for a 300 nm misalignment between III-V and silicon waveguide layer. [9] and [10]. Figure 3c shows the geometry of tri-sectional tapered coupler for EAM devices [10].…”

Demonstration of a discretely tunable III-V/SOI sampled grating distributed feedback laser

“…The III-V epitaxial layer stack constitutes a standard amplifier stack with an n-InP bottom cladding (190 nm thick), 2 InGaAsP SCH layers (100 nm thick, 1.17 µm bandgap wavelength), 6 InGaAsP quantum wells (7 nm thick, 1.55 µm bandgap wavelength), a pInP top cladding (1.5 µm thick) and a p ++ -InGaAs top contact layer (200 nm thick). Coupling between the III-V layer and the SOI output waveguide is realised through a standard double adiabatic tapered coupler, as demonstrated in [8].…”