A thin-film InGaAs/GaAs edge-emitting single-quantum-well laser has been integrated with a tapered multimode SU-8 waveguide onto an Si substrate. The SU-8 waveguide is passively aligned to the laser using mask-based photolithography, mimicking electrical interconnection in Si complementary metal-oxide semiconductor, and overlaps one facet of the thin-film laser for coupling power from the laser to the waveguide. Injected threshold current densities of 260 A=cm 2 are measured with the reduced reflectivity of the embedded laser facet while improving single mode coupling efficiency, which is theoretically simulated to be 77%. © 2010 Optical Society of America OCIS codes: 130.3120, 130.5460, 130.6622, 230.3120, 250.3140, 250.5300.The planar integration of photonic components onto postprocessed Si or Si complementary metal-oxide semiconductor platforms have applications ranging from optical interconnects to environmental/biological/chemical sensing [1][2][3][4][5][6]. A basic building block of these planar photonic chip-scale systems is a thin-film III-V edgeemitting laser (TF-EEL) integrated with a waveguide on the same substrate. To realize low-power, portable, cost-effective chip-scale integrated systems, the laser power consumption must be minimized, the laser to waveguide coupling maximized, and the process technology simplified. Thus, the laser threshold current density, J th , should be low, the waveguide should be optimally coupled with the laser with minimal alignment requirements, and efficient heat sinking strategies should be implemented.Integration of TF-EELs with waveguides has been demonstrated on SiO 2 =Si [7], silicon-on-insulator [8,9], and with polymers [10][11][12], in addition to the characterization of photodetectors with polymer waveguides, for both Si photodiodes [13] and thin-film III-V metal-semiconductor metal photodetectors [11,14]. In [8][9][10][11], both p and n contacts are on the top of the laser, compromising current flow, and the interface between the laser and the substrate is thermally insulating, compromising thermal management. In [7], the TF-EELs are placed in a trench in a slab waveguide, requiring precise control over etch depth and vertical alignment. Likewise,in [8], the simple cleaved hybrid laser has critical alignment requirements with other optical components. The TF-EELs end-fire coupled to waveguides [7,[9][10][11][12] all have an air gap between the laser and the waveguide, except for [9], in which the etched, not cleaved, EEL facet is embedded in the waveguide.In this Letter, we present the planar integration of a 980 nm TF-EEL with one cleaved facet embedded in a multimode SU-8 waveguide on a SiO 2 =Si substrate. This TF-EEL has top and bottom metal contacts, a p-side ridge, an n metal stripe for low J th operation, and a thermally conducting broad area metal contact bond to the SiO 2 =Si integration substrate. There is no gap between the cleaved TF-EEL and the SU-8 waveguide, increasing the coupling efficiency in comparison to systems with a gap. In contrast to pr...