Abstract: An optical modulator for generating quadrature amplitude modulation (nQAM) and phase-shift keying (nPSK) signals with tunable modulation efficiency. The modulator includes a controlling circuit for adjusting the modulation efficiency or modulation depth of the modulator by controlling the direct current (DC) bias.

Abstract: A signal processing method including obtaining, using an optical receiver, a data signal that comprises one or more pairs of pilot tones and a plurality of subcarrier signals, identifying the one or more pairs of pilot tones, determining a local oscillator frequency offset estimation for the data signal using the one or more pairs of pilot tones, wherein the local oscillator frequency offset estimation indicates a frequency offset, and compensating the data signal in accordance with the local oscillator frequency offset estimation. A signal processing method including obtaining, using an optical receiver, a data signal that comprises one or more pairs of pilot tones and a plurality of subcarrier signals, identifying the one or more pairs of pilot tones, determining a chromatic dispersion estimation for the data signal using the one or more pairs of pilot tones, and compensating the data signal in accordance with the chromatic dispersion estimation.

Abstract: An apparatus comprising a waveguide along a longitudinal axis at a first elevation, an optical splitter coupled to a first edge of the waveguide along the longitudinal axis, two or more inverse tapers coupled to a second edge of the optical splitter along the longitudinal axis, and one or more offset inverse tapers that are substantially parallel with the two or more inverse tapers, wherein the one or more offset inverse tapers are along the longitudinal axis at a second elevation.

Abstract: A signal processing method including obtaining, using an optical receiver, a data signal that comprises one or more pairs of pilot tones and a plurality of subcarrier signals, identifying the one or more pairs of pilot tones, determining a local oscillator frequency offset estimation for the data signal using the one or more pairs of pilot tones, wherein the local oscillator frequency offset estimation indicates a frequency offset, and compensating the data signal in accordance with the local oscillator frequency offset estimation. A signal processing method including obtaining, using an optical receiver, a data signal that comprises one or more pairs of pilot tones and a plurality of subcarrier signals, identifying the one or more pairs of pilot tones, determining a chromatic dispersion estimation for the data signal using the one or more pairs of pilot tones, and compensating the data signal in accordance with the chromatic dispersion estimation.

Abstract: A method includes forming a first optical structure with an inverse taper and a separate optical structure on a semiconductor chip. The illustrative method also includes applying a protective structure over the optical structures and patterning the protective structure to expose the separate optical structure. The method further includes removing a portion of the separate optical structure to form a separate trimmed taper separate from, but adjacent to, the first optical structure. The protective structure is then removed from the first optical structure. Apparatuses are also disclosed.

Abstract: An apparatus comprising a modulation block comprising a plurality of modulators, wherein each of the plurality of modulators comprises an optical input port and an optical output port, and wherein all of the optical input ports and all of the optical output ports are positioned on one face of the modulation block. Another apparatus comprising a modulation block comprising one or more Mach-Zehnder modulators (MZMs), wherein each MZM is coupled to an optical input port, an optical output port, and at least one electrical trace, wherein all of the optical input ports and all of the optical output ports are positioned on a first side of the modulation block, and wherein all of the electrical traces are positioned on a second side of the modulation block, and a planar lightwave circuit (PLC) coupled to the modulation block via an optical interface.

Abstract: An electronic driver circuit for use with a modulator such as a segmented Mach-Zehnder Modulator (MZM) is provided. The electronic driver circuit includes a first delay buffer implemented as a first complementary metal-oxide-semiconductor (CMOS) inverter and a second delay buffer implemented as a second CMOS inverter. The second CMOS inverter follows the first CMOS inverter and has a second gate width smaller than a first gate width of the first CMOS inverter. The first CMOS inverter is configured to produce a first delayed electrical signal from a received electrical signal and the second CMOS inverter is configured to produce a second delayed electrical signal from the first delayed electrical signal produced by the first CMOS inverter.

Abstract: An apparatus comprising an optical input configured to receive an optical carrier, an polarization beam splitter configured to forward a first polarized component of the optical carrier along a first light path, and forward a second polarized component of the optical carrier along a second light path, wherein the first polarized component comprises a first polarization that is perpendicular to a second polarization of the second polarized component upon exiting the optical splitter, and an optical modulator coupled to the first light path and the second light path, the modulator configured to modulate the first polarized component of the optical carrier and the second polarized component of the optical carrier.

Abstract: A first optical transceiver node comprises: a laser configured to emit an input optical signal; a first splitter coupled to the laser and configured to split the input optical signal into a local oscillator (LO) optical signal and an unmodulated optical signal; and a receiver coupled to the first splitter and configured to: receive the LO optical signal from the first splitter; receive a modulated optical signal from a second optical transceiver node, wherein the modulated optical signal is a modulated version of the unmodulated optical signal; and perform phase noise cancellation of the modulated optical signal using the LO optical signal.

Abstract: An apparatus comprises an uncooled laser; a splitter coupled to the laser; a first wavelength component coupled to the splitter; a local oscillator (LO) port coupled to the first wavelength component; a modulator coupled to the splitter; a second wavelength component coupled to the modulator; and a signal port coupled to the second wavelength component. A method comprises emitting an input light; splitting the input light into a first local oscillator (LO) optical signal and a first unmodulated optical signal; modulating the first unmodulated optical signal using polarization-multiplexed, high-order modulation to produce a first modulated optical signal; transmitting the first LO optical signal to a first duplex fiber; and transmitting the first modulated optical signal to a second duplex fiber.

Abstract: A system comprises: a polarization state aligner (PSA) comprising: an input port; a first polarization beam splitter (PBS) coupled to the input port; a first phase shifter (PS) coupled to the first PBS; a first polarization rotator (PR) coupled to the first PBS; a first beam splitter (BS) coupled to the first PS and the first PR; a first output port coupled to the first BS; and a second output port coupled to the first BS.

Abstract: An apparatus comprising a first electrical driver configured to generate a first binary voltage signal according to first data, a second electrical driver configured to generate a second binary voltage signal according to second data, wherein the first data and the second data are different, and a first optical waveguide arm coupled to the first electrical driver and the second electrical driver, wherein the first optical waveguide arm is configured to shift a first phase of a first optical signal propagating along the first optical waveguide arm according to a first voltage difference between the first binary voltage signal and the second binary voltage signal to produce a first, multi-level phase-shifted optical signal.

Abstract: A BOSA package comprising only one cylindrical TO package comprising a ROSA and a TOSA, and an optical port in optical communication with the ROSA and the TOSA. Also disclosed is a TO package comprising a TOSA for transmitting a first optical signal, a ROSA for receiving a second optical signal, an optical communication window, and a TFF positioned such that the first optical signal transmitted from the TOSA is reflected by the TFF toward the optical communication window and the second optical signal received from the optical communication window passes through the TFF and to the ROSA.

Abstract: An optical modulator comprising a waveguide for propagating an optical signal comprising a proximate arm configured to communicate a proximate portion of the optical signal, and a distal arm configured to communicate a distal portion of the optical signal, a proximate diode configured to modulate the proximate portion of the optical signal, a distal diode configured to modulate the distal portion of the optical signal, and an electrical input electrically coupled to opposite signed interfaces of the proximate diode and the distal diode such that an electrical driving signal propagated along the electrical input causes an equal and opposite modulation of the proximate portion of the optical signal in the proximate arm of the waveguide and the distal portion of the optical signal in the distal arm of the waveguide.

Abstract: A photonic device comprising a base plate, a photonic laser coupled to the base plate, wherein the photonic laser is configured to generate a light, a lens coupled to the base plate, wherein the lens is configured to receive the light from the photonic laser, form a focused light, and pass the focused light to a reflector, and the reflector incorporated with the base plate such that the lens is positioned between the photonic laser and the reflector, wherein the reflector is configured to receive the focused light, and wherein the reflector is configured to steer a first portion of the focused light through the base plate using total internal reflection.

Abstract: A photonic device comprising a base plate, a photonic laser coupled to the base plate, wherein the photonic laser is configured to generate a light, a lens coupled to the base plate, wherein the lens is configured to receive the light from the photonic laser, form a focused light, and pass the focused light to a reflector, and the reflector incorporated with the base plate such that the lens is positioned between the photonic laser and the reflector, wherein the reflector is configured to receive the focused light, and wherein the reflector is configured to steer a first portion of the focused light through the base plate using total internal reflection.

Abstract: An optical receiver comprising a frontend configured to receive an optical signal and convert the optical signal into a plurality of digital electrical signals comprising a plurality of spectrally shaped subcarrier signals carrying symbol mapped data information, and a digital signal processor (DSP) unit coupled to the frontend and configured to receive the digital signals from the frontend, demulitplex the digital signals into the subcarrier signals, and compensate chromatic dispersion (CD) for each of the subcarrier signals by applying an equalizer, wherein each of the subcarrier signals is associated with a unique tone frequency and a unique spectral shape. Also disclosed is an optical transmitter comprising a digital signal processor (DSP) unit configured to map data symbols onto a plurality of electrical subcarrier signals that are non-overlapping and spectrally shaped in a frequency domain.

Abstract: An optical apparatus, comprising a polarization beam splitter (PBS) comprising a birefringent crystal having a front-end and a back-end, and an optical rotator positioned on the back-end of the birefringent crystal. Included is an optical apparatus comprising a PBS comprising a birefringent crystal and an optical rotator, wherein the PBS is configured to receive a multiplexed optical signal comprising a first polarized optical signal and a second polarized optical signal, wherein the second polarized optical signal is orthogonal to the first polarized optical signal, separate the first polarized optical signal from the second polarized optical signal using the birefringent crystal, and rotate the second polarized optical signal using the optical rotator such that the rotated second polarized optical signal is parallel to the first polarized optical signal. The PBS may further comprise only one lens, wherein the lens is positioned on the front-end of the birefringent crystal.

Abstract: A photonic device comprising a base plate, a photonic laser coupled to the base plate, wherein the photonic laser is configured to generate a light, a lens coupled to the base plate, wherein the lens is configured to receive the light from the photonic laser, form a focused light, and pass the focused light to a reflector, and the reflector incorporated with the base plate such that the lens is positioned between the photonic laser and the reflector, wherein the reflector is configured to receive the focused light, and wherein the reflector is configured to steer a first portion of the focused light through the base plate using total internal reflection.

Abstract: An apparatus comprising a waveguide along a longitudinal axis at a first elevation, an optical splitter coupled to a first edge of the waveguide along the longitudinal axis, two or more inverse tapers coupled to a second edge of the optical splitter along the longitudinal axis, and one or more offset inverse tapers that are substantially parallel with the two or more inverse tapers, wherein the one or more offset inverse tapers are along the longitudinal axis at a second elevation.