Abstract: Two or more monolithic or heterogeneously integrated substrates are attached to each other and optically edge-coupled using spot-size converters. Spot-size converters are placed between planar optical waveguides and cleaved or etched facets in each substrate. The facets are provide optical edge coupling and the spot-size converters are used to adjust at least the size, shape, and divergence of the optical beams entering or exiting the optical waveguides as to improve the optical coupling between the substrates. In addition to spot-size converters, filtering and other light adjusting elements may be placed between the substrates. Integrated lasers, semiconductor optical amplifiers, and photonic integrated circuits can be provided with complementary metal-oxide semiconductor (CMOS)-compatible silicon (Si) photonic substrates, which can also contain integrated electronics.

Abstract: Methods for realizing integrated lasers and photonic integrated circuits on complimentary metal-oxide semiconductor (CMOS)-compatible silicon (Si) photonic chips, potentially containing integrated electronics, are disclosed. The integration techniques rely on light coupling with integrated light coupling elements such as turning mirrors, lenses, and surface grating couplers. Light is coupled from between two or more substrates using the light coupling elements. The technique can realize integrated lasers on Si where a gain flip chip (the second substrate) is bonded to a Si chip (the first substrate) and light is coupled between a waveguide in the gain flip chip to a Si waveguide by way of a turning mirror or grating coupler in the flip chip and a grating coupler in the Si chip. Integrated lenses and other elements such as spot-size converters can also be incorporated to alter the mode from the gain flip chip to enhance the coupling efficiency to the Si chip.

Abstract: A 2n quadrature amplitude modulation optical modulator has an optical input for receiving an optical signal. A first splitter is coupled to the optical input and has first and second outputs. A first optical modulation apparatus, coupled to the first output, applies a modulation scheme having 2n-2 constellation points to produce a first modulated optical signal representing an in-phase component. A second optical modulation apparatus, coupled to the second output, applies a modulation scheme having 2n-2 constellation point to produce a second modulated optical signal representing a quadrature component. An optical combiner combines the first and second modulated optical signals to produce an output modulated optical signal which is modulated with a modulation scheme having 2n constellation points.