Abstract: In example implementations of a heterogeneous substrate, the heterogeneous substrate includes a first material having an air trench, a second material coupled to the first material, a dielectric mask on a first portion of the second material and an active region that is grown on a remaining portion of the second material. An air gap may be formed in the air trench by the second material coupled to the first material. Defects in the second material may be contained to an area below the dielectric mask and the active region may remain defect free.

Abstract: A quantum-dot based avalanche photodiode (QD-APD) may include a silicon substrate and a waveguide on which a quantum dot (QD) stack of layers is formed having a QD light absorption layer, a charge multiplication layer (CML), and spacer layers. The QD stack may be formed within a p-n junction. The waveguide may include a mode converter to facilitate optical coupling and light transfer from the waveguide to the QD light absorption layer. The QD absorption layer and the CML layer may be combined or separate layers. The CML may generate electrical current from the absorbed light with more than 100% quantum efficiency when the p-n junction is reverse-biased.

Abstract: A three-terminal avalanche photodiode provides a first controllable voltage drop across a light absorbing region and a second, independently controllable, voltage drop across a photocurrent amplifying region. The absorbing region may also have a different composition from the amplifying region, allowing further independent optimization of the two functional regions. An insulating layer blocks leakage paths, redirecting photocurrent toward the region(s) of highest avalanche gain. The resulting high-gain, low-bias avalanche photodiodes may be fabricated in integrated optical circuits using commercial CMOS processes, operated by power supplies common to mature computer architecture, and used for optical interconnects, light sensing, and other applications.

Abstract: Examples disclosed herein relate to multi-wavelength semiconductor comb lasers. In some examples disclosed herein, a multi-wavelength semiconductor comb laser may include a waveguide included in an upper silicon layer of a silicon-on-insulator (SOI) substrate. The comb laser may include a quantum dot (QD) active gain region above the SOI substrate defining an active section in a laser cavity of the comb laser and a dispersion tuning section included in the laser cavity to tune total cavity dispersion of the comb laser.

Abstract: A quantum dot comb laser includes a body defining a lasing cavity and an extension defining an external cavity, the FSR of the lasing cavity being an inverse of an integer multiple of the FSR of the external cavity.

Abstract: An example system for multi-wavelength optical signal splitting is disclosed. The example disclosed herein comprises a first splitter, a second splitter, and a modulator. The system receives a multi-wavelength optical signal and an electrical signal, wherein the multi-wavelength optical signal comprises a plurality of optical wavelengths and has a power level. The first splitter is to split the plurality of optical wavelengths into a plurality of optical wavelength groups. The second splitter is to split the multi-wavelength optical signal or the plurality of optical wavelength groups into a plurality of lower power signal groups. The modulator is to encode the electrical signal into the plurality of optical wavelength groups, the plurality of lower power signal groups, or a combination thereof.

Abstract: In example implementations of a heterogeneous substrate, the heterogeneous substrate includes a first material having an air trench, a second material coupled to the first material, a dielectric mask on a first portion of the second material and an active region that is grown on a remaining portion of the second material. An air gap may be formed in the air trench by the second material coupled to the first material. Defects in the second material may be contained to an area below the dielectric mask and the active region may remain defect free.

Abstract: Plasmonic avalanche photodetection employs an optical antenna and an avalanche photodiode (APD) coupled to the optical antenna. Hot carriers generated by light incident on the optical antenna are received in an avalanche multiplication region of the APD where avalanche multiplication of the hot carriers is provided.

Abstract: A multilayer device includes a substrate having a trench extending along a first surface of the substrate. A first layer disposed on the first surface of the substrate, the first layer comprising a given surface and another surface. A dielectric layer is formed between the given surface of the first layer and the first surface of the substrate. An active region disposed on the other surface of the first layer overlying the trench, wherein at least a portion of the active region resides substantially above a region defined by the trench.

Abstract: A quantum dot comb laser includes a body defining a lasing cavity and an extension defining an external cavity, the FSR of the lasing cavity being an inverse of an integer multiple of the FSR of the external cavity.

Abstract: Examples disclosed herein relate to multi-wavelength semiconductor lasers. In some examples disclosed herein, a multi-wavelength semiconductor laser may include a silicon-on-insulator (SOI) substrate and a quantum dot (QD) layer above the SOI substrate. The QD layer may include and active gain region and may have at least one angled junction at one end of the QD layer. The SOI substrate may include a waveguide in an upper silicon layer and a mode converter to facilitate optical coupling of a lasing mode to the waveguide.

Abstract: A hybrid grating comprises a first grating layer composed of a first solid-state material, and a second grating layer over the first grating layer and composed of a second solid-state material, the second solid state-material being different than the first solid-state material and having a monocrystalline structure.

Abstract: Examples disclosed herein relate to multi-wavelength semiconductor lasers. In some examples disclosed herein, a multi-wavelength semiconductor laser may include a silicon-on-insulator (SOI) substrate and a quantum dot (QD) layer above the SOI substrate. The QD layer may include and active gain region and may have at least one angled junction at one end of the QD layer. The SOI substrate may include a waveguide in an upper silicon layer and a mode converter to facilitate optical coupling of a lasing mode to the waveguide.

Abstract: Examples disclosed herein relate to quantum-dot (QD) photonics. In accordance with some of the examples disclosed herein, a QD semiconductor optical amplifier (SOA) may include a silicon substrate and a QD layer above the silicon substrate. The QD layer may include an active gain region to amplify a lasing mode received from an optical signal generator. The QD layer may have a gain recovery time such that the active gain region amplifies the received lasing mode without pattern effects. A waveguide may be included in an upper silicon layer of the silicon substrate. The waveguide may include a mode converter to facilitate optical coupling of the received lasing mode between the QD layer and the waveguide.

Abstract: Examples disclosed herein relate to optical driver circuits. In some of the disclosed examples, an optical driver circuit includes a pre-driver circuit and a main driver circuit. The pre-driver circuit may include a pattern generator and at least one serializer to generate a main modulation signal and an inverted delayed modulation signal. The main driver circuit may include a level controller to control amplitudes of pre-emphasis on rising and falling edges of a modulation signal output and an equalization controller to transition the modulation signal output from the pre-emphasis amplitudes to main modulation amplitudes using the inverted delayed modulation signal.

Abstract: An electronic device with a detachable battery cover is described. The electronic device comprises a device body, a battery cover, a first attachment body disposed on the device body, and a second attachment body disposed on the battery cover. The first attachment body and the second attachment body are attached to each other to connect the device body and the battery cover. The device body and the battery cover of the present disclosure are connect to each other through the first attachment body and the second attachment body so that the battery cover is firmly attached on the electronic device and easy to detach the battery cover. Attachment capacity of the first attachment body and the second attachment body will not be weakened with the increase in the number of detachments so that service life can be extend and the quality of the electronic device can be improved.

Abstract: A photonic integrated circuit (PIC) includes a semiconductor substrate with a main bus waveguide disposed within the substrate. Two or more ring lasers are disposed within the substrate and are optically coupled to the main bus waveguide. The ring lasers have a wavelength control mechanism allowing change of a lasers emitted wavelength. A wavelength selective filter is optically coupled to the bus waveguide. A control circuit is electronically coupled to each wavelength control mechanism, and the wavelength selective filter. The control circuit in conjunction with the selective filter allows monitoring of a ring laser's wavelength on the main bus waveguide. Based on a determined wavelength, the control circuit may change a ring laser wavelength to a desired wavelength to achieve a desired wavelength spacing for each of the ring lasers. The PIC may be integrated as a coarse wave-length division multiplexing (CWDM) transmit module.

Abstract: One example includes a photodetector system. The system includes a waveguide photodetector into which an input optical signal comprising a frequency band of interest is provided and from which the input optical signal is absorbed to generate an output signal that is indicative of an intensity of the input optical signal. The system also includes a reflector coupled to the waveguide photodetector and which is to reject frequencies outside of the frequency band of interest and to reflect the frequency band of interest back into the waveguide photodetector.

Abstract: A hybrid grating comprises a first grating layer composed of a first solid-state material, and a second grating layer over the first grating layer and composed of a second solid-state material, the second solid state-material being different than the first solid-state material and having a monocrystalline structure.

Abstract: A hybrid grating comprises a first grating layer composed of a first solid-state material, and a second grating layer over the first grating layer and composed of a second solid-state material, the second solid state-material being different than the first solid-state material and having a monocrystalline structure.