Abstract: An optical receiver includes an optical detector having an input that is positioned to detect an optical data signal. The optical detector generates a voltage at an output that is proportional to an optical intensity of the optical data signal. A differential amplifier includes a data input that is electrically connected to the output of the optical detector and a decision threshold voltage signal input. The differential amplifier generates a data signal at a data output and an inverse data signal at a data_bar output. A decision threshold voltage signal generator includes an output that is coupled to the decision threshold voltage signal input of the differential amplifier. The decision threshold voltage signal generator generates a decision threshold voltage signal having an amplitude that causes the differential amplifier to maintain a substantially constant differential voltage between the data signal and the inverse data signal generated.

Abstract: An optical receiver includes an optical detector that is positioned to detect an optical data signal received from an optical channel generates a received electrical data signal at an output. An electrical switch passes one of the received electrical data signal and a second electrical signal depending upon a control signal applied to a control input. A data and clock recovery circuit generates a recovered clock and a recovered data signal when a signal-to-noise ratio of the received electrical signal is in a range where a signal locking condition is established, and generates the control signal at the control output that instructs the electrical switch to select the received electrical data signal if the signal locking condition is established and to select the second electrical signal if the signal locking condition is not established.

Abstract: An optical communications system includes an optical transmitter that generates a modulated optical signal at an output. The modulated optical signal propagates through an optical link where the dispersion of the optical link is imprinted onto an optical spectrum of the modulated optical signal. A demodulator receives the modulated optical signal and filters at least a portion of the optical spectrum with the imprinted dispersion of the optical link, thereby mitigating effects of dispersion in the modulated optical signal and generating a demodulated optical signal at an output. An optical detector generates an electrical data signal from the demodulated optical signal.

Abstract: An optical transmitter and methods of generating an optical signal having SBS suppression are described. An optical transmitter having SBS suppression according to the present invention includes a signal generator that generates a SBS suppression signal. A laser generates a line width broadened optical signal having AM noise. A signal processor generates a modified SBS suppression signal from the SBS suppression signal. A modulator modulates the line width broadened optical signal having the AM noise with a payload modulation signal and with the modified SBS suppression signal to generate a payload modulated optical signal having SBS suppression and reduced AM noise.

Abstract: An optical transmitter and methods of generating an optical signal having SBS suppression are described. An optical transmitter having SBS suppression according to the present invention includes a signal generator that generates a SBS suppression signal. A laser generates a line width broadened optical signal having AM noise. A signal processor generates a modified SBS suppression signal from the SBS suppression signal. A modulator modulates the line width broadened optical signal having the AM noise with a payload modulation signal and with the modified SBS suppression signal to generate a payload modulated optical signal having SBS suppression and reduced AM noise.

Abstract: Apparatus and methods for linearizing an optical transmitter are described. A linearized optical transmitter according to the present invention includes a modulator bias voltage supply that biases an optical modulator. The optical modulator modulates an optical signal with a payload modulation signal. A feedback circuit receives electrical distortion signals generated by the modulator and generates a control signal in response to at least one of the electrical distortion signals. The control signal changes the bias voltage generated by the modulator bias voltage supply so as to reduce the at least one electrical distortion signal.

Abstract: A multi-mode optical fiber link is described that includes a single-mode optical fiber having an input that receives an optical signal for transmission through the multi-mode optical fiber link. A first spatial mode converter is coupled to the single-mode optical fiber. The first spatial mode converter conditions a modal profile of the optical signal for propagation through a multi-mode optical fiber. A multi-mode optical fiber is coupled to an output of the first spatial mode converter. A second spatial mode converter is coupled to an output of the multi-mode optical fiber. The second spatial mode converter reduces a number of optical modes in the optical signal. Both the first and the second spatial mode converters increase an effective modal bandwidth of the optical signal propagating through an output of the second spatial mode converter.

Abstract: An optical transmitter for an optical fiber transmission system is described. The optical transmitter includes an optical source that generates an optical signal having a wavelength at an output. An optical intensity modulator modulates the optical signal with an electrical modulation signal to generate a modulated optical signal at an output. At least one parameter of the optical intensity modulator is chosen to suppress at least one of phase and sideband information in the modulated optical signal. An optical fiber is coupled to the output of the optical intensity modulator. The suppression of the at least one of the phase and the sideband information in the modulated optical signal increases an effective modal bandwidth of the optical fiber.

Abstract: An optical transmitter and methods of generating an optical signal having SBS suppression are described. An optical transmitter having SBS suppression according to the present invention includes a signal generator that generates a SBS suppression signal. A laser generates a line width broadened optical signal having AM noise. A signal processor generates a modified SBS suppression signal from the SBS suppression signal. A modulator modulates the line width broadened optical signal having the AM noise with a payload modulation signal and with the modified SBS suppression signal to generate a payload modulated optical signal having SBS suppression and reduced AM noise.

Abstract: An electra-absorption modulator and electra-absorption modulated laser are described that include a semiconductor layer having an electrically controllable absorption. The material composition of the semiconductor layer is chosen so that the semiconductor layer is substantially transparent to light propagating through the semiconductor layer when a substantially zero or a reverse bias voltage is applied across the semiconductor layer at operating temperatures of the electro-absorption modulator that are substantially greater than 25 degrees Celsius.

Abstract: An integrated laser device includes a pre-distortion circuit. The pre-distortion circuit receives an electrical modulation signal and generates a pre-distorted modulation signal. A laser is integral with the pre-distortion circuit. The laser includes an electrical modulation input that is connected to the output of the pre-distortion circuit. The laser modulates an optical signal with the pre-distorted modulation signal. The pre-distorted modulation signal causes at least some vector cancellation of distortion signals generated when the laser modulates the optical signal.

Abstract: An optical transmitter for an optical fiber transmission system is described. The optical transmitter includes an optical source that generates an optical signal having a wavelength at an output. An optical intensity modulator modulates the optical signal with an electrical modulation signal to generate a modulated optical signal at an output. At least one parameter of the optical intensity modulator is chosen to suppress at least one of phase and sideband information in the modulated optical signal. An optical fiber is coupled to the output of the optical intensity modulator. The suppression of the at least one of the phase and the sideband information in the modulated optical signal increases an effective modal bandwidth of the optical fiber.

Abstract: A multi-mode optical fiber link is described that includes a single-mode optical fiber having an input that receives an optical signal for transmission through the multi-mode optical fiber link. A first spatial mode converter is coupled to the single-mode optical fiber. The first spatial mode converter conditions a modal profile of the optical signal for propagation through a multi-mode optical fiber. A multi-mode optical fiber is coupled to an output of the first spatial mode converter. A second spatial mode converter is coupled to an output of the multi-mode optical fiber. The second spatial mode converter reduces a number of optical modes in the optical signal. Both the first and the second spatial mode converters increase an effective modal bandwidth of the optical signal propagating through an output of the second spatial mode converter.

Abstract: A multi-mode optical fiber link is described. The multi-mode optical fiber link includes a first spatial mode converter that is coupled to a first single mode optical fiber. The first spatial mode converter conditions a modal profile of an optical signal propagating from the single mode optical fiber to the first spatial mode converter. A multi-mode optical fiber is coupled to the first spatial mode converter. A second spatial mode converter is coupled to an output of the multi-mode optical fiber and to a second single mode optical fiber. The second spatial mode converter reduces a number of optical modes in the optical signal. Both the first and the second spatial mode converters increase an effective modal bandwidth of the optical signal.

Abstract: Apparatus and methods for linearizing an optical transmitter are described. A linearized optical transmitter according to the present invention includes a modulator bias voltage supply that biases an optical modulator. The optical modulator modulates an optical signal with a payload modulation signal. A feedback circuit receives electrical distortion signals generated by the modulator and generates a control signal in response to at least one of the electrical distortion signals. The control signal changes the bias voltage generated by the modulator bias voltage supply so as to reduce the at least one electrical distortion signal.