Abstract: A conductive terminal includes a conductive base substrate and a plating layer structure plated on the conductive base substrate. The plating layer structure includes a nickel plating layer located outside the conductive base substrate, a silver plating layer located outside the nickel plating layer, and a platinum-based polymetallic plating layer located outside the silver plating layer.

Abstract: An optical frequency comb light source and an optical frequency comb generation method, where the light source includes a laser diode, a coupler, a Kerr nonlinear device, a beam splitter, and a phase shifter. The laser diode is connected to one input port of the coupler, and the other input port of the coupler is connected to an output port of the phase shifter. An output port of the coupler is connected to an input port of the Kerr nonlinear device. An output port of the Kerr nonlinear device is connected to an input port of the beam splitter. One output port of the beam splitter is connected to an input port of the phase shifter. The other output port of the beam splitter is configured to output a plurality of optical frequency combs. A multi-wavelength light source with relatively high power may be provided.

Abstract: Semiconductor structure and its fabrication method are provided. The method includes providing a substrate, where the substrate includes a first region having a first metal structure and a second region having a second metal structure; forming a device layer on each of top surfaces of the substrate, the first metal structure and the second metal structure; forming a first through hole in the device layer at the first region, where the first through hole exposes at least a portion of surfaces of the first metal structure, and forming a second through hole in the device layer at the second region, where the second through hole passes through the first device and exposes at least a portion of surfaces of the second metal structure; and using a selective metal growth process, forming a first plug in the first through hole and forming a second plug in the second through hole.

Abstract: Digital to analog converter generates an analog output corresponding to a digital input by controlling DAC cells using bits of the digital input. The DAC cells individually make a contribution to the analog output. Due to process, voltage, and temperature variations, the DAC cells may have duty cycle error or mismatches. To compensate for the duty cycle error of a DAC cell, a small amount of charge is injected into a low-impedance node of a DAC cell when the data signal driving the DAC cell transitions, or changes state. The small amount of charge is generated using a capacitive T-network, and the polarity of the charge injected is opposite of the error charge caused by duty cycle error. The opposite amount of charge thus compensates or cancels out the duty cycle error, and duty cycle error present at the output of the DAC cell is reduced.

Abstract: A tunable laser includes a reflective semiconductor optical amplifier (SOA), a grating codirectional coupler, and a reflective microring resonator. The grating codirectional coupler and the reflective microring resonator are both formed on a silicon base. An anti-reflection film is disposed on a first end surface of the reflective SOA, and the first end surface is an end surface, coupled to a first waveguide of the grating codirectional coupler, of the reflective SOA. A second waveguide of the grating codirectional coupler is coupled to the first waveguide, a first grating is disposed on the first waveguide, a second grating disposed opposite to the first grating is disposed on the second waveguide, and the first grating and the second grating constitute a narrow-band pass filter. The second waveguide is connected to the reflective microring resonator.

Abstract: This application provides an example light source switching apparatus. The apparatus includes first and second multi-mode interference (MMI) couplers, and a phase modulator. The first MMI coupler includes four ports, where first and second ports are located on one side, and third and fourth ports are located on the other side. The second MMI coupler includes three ports, where fifth and sixth ports are located on one side, and a seventh port is located on the other side. The first and the second ports connect to the fifth and the sixth ports, respectively, to form two connections. The phase modulator is disposed on one of the two connections, and the seventh port connects to an optical modulator. Both the third and the fourth ports connect to a light source emitting continuous light, and the phase modulator selects one of the two light sources for output from the seventh port.

Abstract: Digital to analog converter generates an analog output corresponding to a digital input by controlling DAC cells using bits of the digital input. The DAC cells individually make a contribution to the analog output. Due to process, voltage, and temperature variations, the DAC cells may have duty cycle error or mismatches. To compensate for the duty cycle error of a DAC cell, a small amount of charge is injected into a low-impedance node of a DAC cell when the data signal driving the DAC cell transitions, or changes state. The small amount of charge is generated using a capacitive T-network, and the polarity of the charge injected is opposite of the error charge caused by duty cycle error. The opposite amount of charge thus compensates or cancels out the duty cycle error, and duty cycle error present at the output of the DAC cell is reduced.

Abstract: This application provides an example light source switching apparatus. The apparatus includes first and second multi-mode interference (MMI) couplers, and a phase modulator. The first MMI coupler includes four ports, where first and second ports are located on one side, and third and fourth ports are located on the other side. The second MMI coupler includes three ports, where fifth and sixth ports are located on one side, and a seventh port is located on the other side. The first and the second ports connect to the fifth and the sixth ports, respectively, to form two connections. The phase modulator is disposed on one of the two connections, and the seventh port connects to an optical modulator. Both the third and the fourth ports connect to a light source emitting continuous light, and the phase modulator selects one of the two light sources for output from the seventh port.

Abstract: An optical frequency comb light source and an optical frequency comb generation method, where the light source includes a laser diode, a coupler, a Kerr nonlinear device, a beam splitter, and a phase shifter. The laser diode is connected to one input port of the coupler, and the other input port of the coupler is connected to an output port of the phase shifter. An output port of the coupler is connected to an input port of the Kerr nonlinear device. An output port of the Kerr nonlinear device is connected to an input port of the beam splitter. One output port of the beam splitter is connected to an input port of the phase shifter. The other output port of the beam splitter is configured to output a plurality of optical frequency combs. A multi-wavelength light source with relatively high power may be provided.

Abstract: Digital to analog conversion generates an analog output corresponding to a digital input by controlling unit elements or cells using data bits of the digital input. The unit elements or cells individually make a contribution to the analog output. Due to process, voltage, and temperature variations, the unit elements or cells may have mismatches and/or errors. The mismatches and/or errors can degrade the quality of the analog output. To extract the mismatches and/or errors, a transparent dither can be used. The mismatches and/or errors can be extracted by observing the analog output, and performing a cross-correlation of the observed output with a switching bit stream of the dither. Once extracted, the unit elements or cells can be adjusted accordingly to reduce the respective mismatches and/or errors.

Abstract: This application provides an example light source switching apparatus. The apparatus includes first and second multi-mode interference (MMI) couplers, and a phase modulator. The first MMI coupler includes four ports, where first and second ports are located on one side, and third and fourth ports are located on the other side. The second MMI coupler includes three ports, where fifth and sixth ports are located on one side, and a seventh port is located on the other side. The first and the second ports connect to the fifth and the sixth ports, respectively, to form two connections. The phase modulator is disposed on one of the two connections, and the seventh port connects to an optical modulator. Both the third and the fourth ports connect to a light source emitting continuous light, and the phase modulator selects one of the two light sources for output from the seventh port.

Abstract: Digital to analog conversion generates an analog output corresponding to a digital input by controlling unit elements or cells using data bits of the digital input. The unit elements or cells individually make a contribution to the analog output. Due to process, voltage, and temperature variations, the unit elements or cells may have mismatches. The mismatches can degrade the quality of the analog output. To extract the mismatches, a transparent dither can be used. The mismatches can be extracted by observing the analog output, and performing a cross-correlation of the observed output with the dither. Once extracted, the unit elements or cells can be adjusted accordingly to reduce the mismatches.

Abstract: A multi-wavelength laser includes a reference wavelength-tunable laser, N?1 secondary wavelength-tunable lasers, N beam splitters, a phase modulator, and N?1 frequency difference detection apparatuses. The reference wavelength-tunable laser is connected to one beam splitter, the beam splitter includes two output ports, and one of the output ports is connected to the phase modulator. The phase modulator is separately connected to the N?1 frequency difference detection apparatuses. The N?1 secondary wavelength-tunable lasers one-to-one correspond to remaining N?1 beam splitters and the N?1 frequency difference detection apparatuses. The secondary wavelength-tunable laser is connected to a corresponding beam splitter, the corresponding beam splitter includes two output ports, and one of the output ports is connected to a corresponding frequency difference detection apparatus. N is a positive integer not less than 2.

Abstract: Semiconductor structure and its fabrication method are provided. The method includes providing a substrate, where the substrate includes a first region having a first metal structure and a second region having a second metal structure; forming a device layer on each of top surfaces of the substrate, the first metal structure and the second metal structure; forming a first through hole in the device layer at the first region, where the first through hole exposes at least a portion of surfaces of the first metal structure, and forming a second through hole in the device layer at the second region, where the second through hole passes through the first device and exposes at least a portion of surfaces of the second metal structure; and using a selective metal growth process, forming a first plug in the first through hole and forming a second plug in the second through hole.

Abstract: Digital to analog conversion generates an analog output corresponding to a digital input by controlling unit elements or cells using data bits of the digital input. The unit elements or cells individually make a contribution to the analog output. Due to process, voltage, and temperature variations, the unit elements or cells may have mismatches. The mismatches can degrade the quality of the analog output. To extract the mismatches, a transparent dither can be used. The mismatches can be extracted by observing the analog output, and performing a cross-correlation of the observed output with the dither. Once extracted, the unit elements or cells can be adjusted accordingly to reduce the mismatches.

Abstract: Digital to analog conversion generates an analog output corresponding to a digital input by controlling unit elements or cells using data bits of the digital input. The unit elements or cells individually make a contribution to the analog output. Due to process, voltage, and temperature variations, the unit elements or cells may have mismatches. The mismatches can degrade the quality of the analog output. To extract the mismatches, a transparent dither can be used. The mismatches can be extracted by observing the analog output, and performing a cross-correlation of the observed output with the dither. Once extracted, the unit elements or cells can be adjusted accordingly to reduce the mismatches.

Abstract: Digital to analog conversion generates an analog output corresponding to a digital input by controlling unit elements or cells using data bits of the digital input. The unit elements or cells individually make a contribution to the analog output. Due to process, voltage, and temperature variations, the unit elements or cells may have mismatches. The mismatches can degrade the quality of the analog output. To extract the mismatches, a transparent dither can be used. The mismatches can be extracted by observing the analog output, and performing a cross-correlation of the observed output with the dither. Once extracted, the unit elements or cells can be adjusted accordingly to reduce the mismatches.

Abstract: Example wavelength tunable lasers are described. One example wavelength tunable laser includes a reflective semiconductor optical amplifier, three couplers, and at least two microring resonators. The reflective semiconductor optical amplifier is connected to one port of the first coupler. Some of the at least two microring resonators are arranged between another port of the first coupler and one port of the second coupler, the others of the at least two microring resonators are arranged between a third port of the first coupler and a second port of the second coupler, and a third port and a fourth port of the second coupler are connected to two ports of the third coupler.

Abstract: A tunable laser includes a reflective semiconductor optical amplifier (SOA), a grating codirectional coupler, and a reflective microring resonator. The grating codirectional coupler and the reflective microring resonator are both formed on a silicon base. An anti-reflection film is disposed on a first end surface of the reflective SOA, and the first end surface is an end surface, coupled to a first waveguide of the grating codirectional coupler, of the reflective SOA. A second waveguide of the grating codirectional coupler is coupled to the first waveguide, a first grating is disposed on the first waveguide, a second grating disposed opposite to the first grating is disposed on the second waveguide, and the first grating and the second grating constitute a narrow-band pass filter. The second waveguide is connected to the reflective microring resonator.