Abstract: Disclosed are a laser structure and a method for fabricating the laser structure. The method includes: providing an epitaxial structure, the epitaxial structure including a substrate, a first doped dielectric layer, a multiple quantum well active layer and a ridge-shaped doped dielectric layer stacked in sequence; forming a grating structure on the ridge-shaped doped dielectric layer and forming a reflective surface on one end of the grating structure, the reflective surface and the grating structure are defined by a same lithography mask, and the mask is protected in a semiconductor etching process selectively, ensuring that relative positions of the reflective surface and the grating structure are not changed, so that light reflected from the reflective surface back to laser cavity has a predetermined phase defined by design, therefore improves performance and stability of the laser, reduces complexity and cost of the fabrication process, and increases yield and reliability.

Abstract: Disclosed is a surface etched grating semiconductor laser with periodic pumping structure. The structure includes a lower doped dielectric layer, a multiple quantum well active layer, a ridge-shaped doped dielectric layer, periodic grating grooves formed on the ridge-shaped doped dielectric layer and a top electrical contact layer forming ohmic electrical contact with electrical contact regions between the grating grooves. Carriers are injected through the periodic electrical contact layer, flow through the electrical contact regions, spread laterally when reaching the bottom of the grating grooves, and then continue to spread to the multiple quantum well active layer. In a case of uniform distribution, a laser based on refractive index modulation is realized. In a case of non-uniform distribution, a laser with mixed modulation is realized by introducing additional gain modulation.

Abstract: The invention describes an integrated photonics platform comprising a plurality of at least three vertically-stacked waveguides which enables light transfer from one waveguide of the photonic structure into another waveguide by means of controlled tunneling method. The light transfer involves at least three waveguides wherein light power flows from initial waveguide into the final waveguide while tunneling through the intermediate ones. As an exemplary realization of the controlled tunneling waveguide integration, the invention describes a photonic integrated structure consisting of laser guide as upper waveguide, passive guide as middle waveguide, and modulator guide as lower waveguides. Controlled tunneling is enabled by the overlapped lateral tapers formed on the same or different vertical waveguide levels. In the further embodiments, the controlled tunneling platform is modified to implement wavelength-(de)multiplexing, polarization-splitting and beam-splitting functions.

Abstract: Disclosed herein is a monolithically integrated coherent receiver chip which has a geometric arrangement of the on-chip components that significantly improves the performance and the manufacturability of a coherent receiver module for Dual Polarization Quadrature Phase Shift Keyed (DP-QPSK) applications and other optical coherent detection systems. The coherent receiver chip comprises two optical hybrids, three optical inputs and eight electrical outputs with the two optical hybrids oriented perpendicular to the optical inputs and the electrical outputs which are widely spaced and arranged in a co-linear fashion that simplifies module design and assembly. The proposed geometric arrangement also replaces any optical waveguide crossings with vertical electrical-optical crossings and includes electrical transmissions which are used to minimize channel skew. The proposed configuration also has the additional benefit of improved thermal management by separating the module's trans-impedance amplifiers.

Abstract: The invention describes an integrated photonics platform comprising a plurality of at least three vertically-stacked waveguides which enables light transfer from one waveguide of the photonic structure into another waveguide by means of controlled tunneling method. The light transfer involves at least three waveguides wherein light power flows from initial waveguide into the final waveguide whilst tunneling through the intermediate ones. As an exemplary realization of the controlled tunneling waveguide integration, the invention describes a photonic integrated structure consisting of laser guide as upper waveguide, passive guide as middle waveguide, and modulator guide as lower waveguides. Controlled tunneling is enabled by the overlapped lateral tapers formed on the same or different vertical waveguide levels. In the further embodiments, the controlled tunneling platform is modified to implement wavelength-(de)multiplexing, polarization-splitting and beam-splitting functions.

Abstract: Disclosed herein is a monolithically integrated coherent receiver chip which has a geometric arrangement of the on-chip components that significantly improves the performance and the manufacturability of a coherent receiver module for Dual Polarization Quadrature Phase Shift Keyed (DP-QPSK) applications and other optical coherent detection systems. The coherent receiver chip comprises two optical hybrids, three optical inputs and eight electrical outputs with the two optical hybrids oriented perpendicular to the optical inputs and the electrical outputs which are widely spaced and arranged in a co-linear fashion that simplifies module design and assembly. The proposed geometric arrangement also replaces any optical waveguide crossings with vertical electrical-optical crossings and includes electrical transmissions which are used to minimize channel skew. The proposed configuration also has the additional benefit of improved thermal management by separating the module's trans-impedance amplifiers.

Abstract: A frequency synthesiser for generating wideband signals for zero Hz up to frequencies in the millimetre wave band provides the ability for arbitrarily fine increments in output frequency. The synthesiser has an optical comb generator that provides a set of reference signals at predetermined intervals. These reference signals are fed to two or more laser devices, at least one of which is a frequency selection and translation device capable of selecting a particular output line from the comb generator and shifting it by some desired frequency. The outputs from the laser devices are then combined and detected using a photodetector. The output from this is the system output. Various methods of producing the frequency selection and translation device are disclosed, as are various methods of producing the optical comb reference signal. Some possible applications of the invention are also disclosed.

Abstract: A frequency synthesiser for generating wideband signals for zero Hz up to frequencies in the millimetre wave band provides the ability for arbitrarily fine increments in output frequency. The synthesiser has an optical comb generator that provides a set of reference signals at predetermined intervals. These reference signals are fed to two or more laser devices, at least one of which is a frequency selection and translation device capable of selecting a particular output line from the comb generator and shifting it by some desired frequency. The outputs from the laser devices are then combined and detected using a photodetector. The output from this is the system output. Various methods of producing the frequency selection and translation device are disclosed, as are various methods of producing the optical comb reference signal. Some possible applications of the invention are also disclosed.