Abstract: A method and apparatus that cancels or reduces DC offset in a fully-differential optical receiver. The method includes receiving differential optical signals, converting, with photodetectors, the differential optical signals to differential current signals representative of the differential optical signals, converting, using a transimpedance amplifier, the differential current signals to differential intermediate voltage signals, amplifying, using a main amplifier, the differential intermediate voltage signals to generate differential output voltage signals, and cancelling a DC component of the differential output voltage signals using a fully differential DC cancellation circuit. Output offset may also be cancelled or reduced using digital control.

Abstract: A method and apparatus that cancels or reduces DC offset in a fully-differential optical receiver. The method includes receiving differential optical signals, converting, with photodetectors, the differential optical signals to differential current signals representative of the differential optical signals, converting, using a transimpedance amplifier, the differential current signals to differential intermediate voltage signals, amplifying, using a main amplifier, the differential intermediate voltage signals to generate differential output voltage signals, and cancelling a DC component of the differential output voltage signals using a fully differential DC cancellation circuit. Output offset may also be cancelled or reduced using digital control.

Abstract: An integrated optical transceiver, comprising a laser component, comprising an array of VCSEL diodes formed on a laser diode substrate; a laser driving component, comprising laser diode driving circuitry formed on a laser driving circuitry substrate; a photodiode component, comprising an array of photodiodes formed on a photodiode substrate; and a photodiode driving component, comprising photodiode driving circuitry formed on a photodiode driving circuitry substrate; a first heat sink comprising a connected piece of material to transport excess heat away from the integrated optical transceiver and connected to both the laser and photodiode driving components; and an electrically insulating material separating the photodiode substrate from the first heat sink and being air or dielectric material with a relative dielectric constant ?<10, wherein the electrically insulating material provides a gap having an effective electrical distance of at least 80 ?m between the photodiode substrate and the first heat sin

Abstract: An integrated optical transceiver, comprising a laser component, comprising an array of VCSEL diodes formed on a laser diode substrate; a laser driving component, comprising laser diode driving circuitry formed on a laser driving circuitry substrate; a photodiode component, comprising an array of photodiodes formed on a photodiode substrate; and a photodiode driving component, comprising photodiode driving circuitry formed on a photodiode driving circuitry substrate; a first heat sink comprising a connected piece of material to transport excess heat away from the integrated optical transceiver and connected to both the laser and photodiode driving components; and an electrically insulating material separating the photodiode substrate from the first heat sink and being air or dielectric material with a relative dielectric constant ?<10, wherein the electrically insulating material provides a gap having an effective electrical distance of at least 80 ?m between the photodiode substrate and the first heat si

Abstract: A device that includes a multi-segment ring modulator is provided. In particular, the device comprises: an optical waveguide; an optical ring modulator optically coupled to the optical waveguide; a first voltage control device along a first segment of the optical ring modulator; a second voltage control device along a second segment of the optical ring modulator; a first driver device configured to control the first voltage control device to a first voltage and a second voltage; and, a second driver device configured to control the second voltage control device to a third voltage and a fourth voltage. In particular implementations, a ratio of a length of the first segment to a length of the second segment can be one or more of about 2:1 and greater than 1:1, and non-linear driver devices can be used.

Abstract: An optical signal is received at a coherent optical receiver. The received optical signal is converted to a first electrical signal and a second electrical signal through a first photodetector and a second photodetector, respectively. The first electrical signal is input into a first single input variable gain amplifier, and the second electrical signal is input into a second single input variable gain amplifier. A gain of at least one of the first single input variable gain amplifier or the second single input variable gain amplifier is controlled to balance the output of the first single input variable gain amplifier and the output of the second single input variable gain amplifier. The output of the first single input variable gain amplifier and the output of the second single input variable gain amplifier are input into a differential amplifier. A receiver output is obtained at an output of the differential amplifier.

Abstract: A device that includes a multi-segment ring modulator is provided. In particular, the device comprises: an optical waveguide; an optical ring modulator optically coupled to the optical waveguide; a first voltage control device along a first segment of the optical ring modulator; a second voltage control device along a second segment of the optical ring modulator; a first driver device configured to control the first voltage control device to a first voltage and a second voltage; and, a second driver device configured to control the second voltage control device to a third voltage and a fourth voltage. In particular implementations, a ratio of a length of the first segment to a length of the second segment can be one or more of about 2:1 and greater than 1:1, and non-linear driver devices can be used.

Abstract: An apparatus, system and method of resonance wavelength alignment for ring modulators is provided which includes: an optical input bus configured to convey a given optical input signal having a given optical frequency; an optical ring modulator configured to: receive and modulate the input signal from the input bus; an optical output bus configured to convey a modulated optical signal from the ring; a first optical tap on the input bus configured to sample the input signal; a second optical tap configured to sample the modulated signal; a controller in communication with the ring, the first tap and the second tap, the controller configured to: determine a current insertion loss of the ring from respective signals received from both the first tap and the second tap; and, control the ring in a feedback loop with the current insertion loss until the current insertion loss comprises a given insertion loss.

Abstract: An optical signal is received at a coherent optical receiver. The received optical signal is converted to a first electrical signal and a second electrical signal through a first photodetector and a second photodetector, respectively. The first electrical signal is input into a first single input variable gain amplifier, and the second electrical signal is input into a second single input variable gain amplifier. A gain of at least one of the first single input variable gain amplifier or the second single input variable gain amplifier is controlled to balance the output of the first single input variable gain amplifier and the output of the second single input variable gain amplifier. The output of the first single input variable gain amplifier and the output of the second single input variable gain amplifier are input into a differential amplifier. A receiver output is obtained at an output of the differential amplifier.

Abstract: An optical signal is received at a coherent optical receiver. The received optical signal is converted to a first electrical signal and a second electrical signal through a first photodetector and a second photodetector, respectively. The first electrical signal is input into a first single input variable gain amplifier, and the second electrical signal is input into a second single input variable gain amplifier. A gain of at least one of the first single input variable gain amplifier or the second single input variable gain amplifier is controlled to balance the output of the first single input variable gain amplifier and the output of the second single input variable gain amplifier. The output of the first single input variable gain amplifier and the output of the second single input variable gain amplifier are input into a differential amplifier. A receiver output is obtained at an output of the differential amplifier.

Abstract: An upstream multiplexer multiplexes data into first and second serialized data streams based on first and second low frequency clocks each derived from a high frequency clock. A downstream multiplexer multiplexes the first and second serialized data streams into a third serialized data stream based on the high frequency clock. A timing error detector derives an error signal indicative of a phase-misalignment between the high frequency clock and the first and second serialized data bit streams based on the high frequency clock and the first and second low frequency clocks. A phase adjuster adjusts phases of the first and second low frequency clocks relative to the high frequency clock based on the error signal so as to reduce the phase-misalignment.

Abstract: An apparatus and methods for generating multi-level output signals for use by an optical modulator are provided. The apparatus comprises a plurality of input signal lines each configured to receive a binary input signal, an output signal line and a plurality of amplifier stages. The amplifier stages are each connected between one of the input signal lines and the output signal line so as to each produce an output voltage on the output signal line of either a first level or a second level. The level of the output voltage is based on the binary signal at the respective input signal line, and the output voltages of the respective plurality of amplifier stages collectively produce a summed analog output voltage on the output signal line at two or more different levels each configured to drive an optical modulator.

Abstract: An optical signal is received at a coherent optical receiver. The received optical signal is converted to a first electrical signal and a second electrical signal through a first photodetector and a second photodetector, respectively. The first electrical signal is input into a first single input variable gain amplifier, and the second electrical signal is input into a second single input variable gain amplifier. A gain of at least one of the first single input variable gain amplifier or the second single input variable gain amplifier is controlled to balance the output of the first single input variable gain amplifier and the output of the second single input variable gain amplifier. The output of the first single input variable gain amplifier and the output of the second single input variable gain amplifier are input into a differential amplifier. A receiver output is obtained at an output of the differential amplifier.

Abstract: An upstream multiplexer multiplexes data into first and second serialized data streams based on first and second low frequency clocks each derived from a high frequency clock. A downstream multiplexer multiplexes the first and second serialized data streams into a third serialized data stream based on the high frequency clock. A timing error detector derives an error signal indicative of a phase-misalignment between the high frequency clock and the first and second serialized data bit streams based on the high frequency clock and the first and second low frequency clocks. A phase adjuster adjusts phases of the first and second low frequency clocks relative to the high frequency clock based on the error signal so as to reduce the phase-misalignment.

Abstract: An apparatus and methods for generating multi-level output signals for use by an optical modulator are provided. The apparatus comprises a plurality of input signal lines each configured to receive a binary input signal, an output signal line and a plurality of amplifier stages. The amplifier stages are each connected between one of the input signal lines and the output signal line so as to each produce an output voltage on the output signal line of either a first level or a second level. The level of the output voltage is based on the binary signal at the respective input signal line, and the output voltages of the respective plurality of amplifier stages collectively produce a summed analog output voltage on the output signal line at two or more different levels each configured to drive an optical modulator.

Abstract: An optical transmitter that controls the extinction ratio by modulating a power level of an optical signal using a frequency spread tone. An electro-optic transducer driver generates an electrical signal that is to be converted into an optical signal. Meanwhile, a tone generator generates an electrical tone having a relatively narrow frequency spectrum. A frequency spreading circuit frequency spreads the electrical tone. A modulator modulates a power level of the electrical signal using the frequency spread electrical tone. An electro-optic transducer then converts the modulated electrical signal into a corresponding optical signal. An optoelectronic transducer recovers the modulated electrical signal by monitoring the optical signal. The tone is then recovered from the signal, and demodulated. The demodulated tone is then used to control the extinction ratio.

Abstract: An optical transmitter that controls the extinction ratio by modulating a power level of an optical signal using a frequency spread tone. An electro-optic transducer driver generates an electrical signal that is to be converted into an optical signal. Meanwhile, a tone generator generates an electrical tone having a relatively narrow frequency spectrum. A frequency spreading circuit frequency spreads the electrical tone. A modulator modulates a power level of the electrical signal using the frequency spread electrical tone. An electro-optic transducer then converts the modulated electrical signal into a corresponding optical signal. An optoelectronic transducer recovers the modulated electrical signal by monitoring the optical signal. The tone is then recovered from the signal, and demodulated. The demodulated tone is then used to control the extinction ratio.

Abstract: Systems and methods for compensating transitions in a data stream to account for jitter including laser jitter. Transitions in the data stream are delayed or advanced depending on the laser jitter and/or whether the previous transition is a rising or falling transition. The compensation of transitions is non-linear such that compensation applied to a rising transition is not necessarily the same as compensation applied to a falling transition. A history of more than one or more bits or transitions of the data stream can be used to further adjust the compensation of transitions in the data stream. When a transition is detected, the bit following the detected transition is peaked either positively or negatively such that the following transition is accordingly delayed or advanced.

Abstract: An optical transmitter that determines and controls the extinction ratio of an optical signal by modulating the duty cycle of the optical signal. The transmitter obtains a signal from the monitor circuit that represents optical power emitted by the electro-optic transducer during normal conditions in which the duty cycle of the optical signal is between a bias high and bias low modulation condition. The transmitter also obtains a signal from the monitor circuit that represents optical power emitted during the bias high modulation condition in which the time at the optical high power level in the eye diagram is greater. Also, the transmitter obtains a signal that represents optical power emitted by the electro-optic transducer during the bias low modulation condition in which the time at the optical low power level in the eye diagram is greater. Based on these signals, the transmitter then derives the extinction ratio.

Abstract: An optical transmitter that determines and controls the extinction ratio of an optical signal by modulating the duty cycle of the optical signal. The transmitter obtains a signal from the monitor circuit that represents optical power emitted by the electro-optic transducer during normal conditions in which the duty cycle of the optical signal is between a bias high and bias low modulation condition. The transmitter also obtains a signal from the monitor circuit that represents optical power emitted during the bias high modulation condition in which the time at the optical high power level in the eye diagram is greater. Also, the transmitter obtains a signal that represents optical power emitted by the electro-optic transducer during the bias low modulation condition in which the time at the optical low power level in the eye diagram is greater. Based on these signals, the transmitter then derives the extinction ratio.