Abstract: An optical communication device may include a driver component, arranged to achieve a driving voltage, and a modulator component, including a laser or arranged to receive light from a laser. The modulator component may be arranged to achieve a modulated light signal modulated based on the driving voltage. The device may include a transmission line arranged to transfer the driving voltage between the driver component and the modulator component. The transmission line may not impedance matched to the driver component, the transmission line may have an impedance which is at least 20% lower than an output impedance of the driver component, and the transmission line may be impedance matched with respect to signal reflections to the modulator component.

Abstract: An optical communication device may include a driver component, arranged to achieve a driving voltage, and a modulator component, including a laser or arranged to receive light from a laser. The modulator component may be arranged to achieve a modulated light signal modulated based on the driving voltage. The device may include a transmission line arranged to transfer the driving voltage between the driver component and the modulator component. The transmission line may not impedance matched to the driver component, the transmission line may have an impedance which is at least 20% lower than an output impedance of the driver component, and the transmission line may be impedance matched with respect to signal reflections to the modulator component.

Abstract: An optical communication device may include a driver component, arranged to achieve a driving voltage, and a modulator component, including a laser or arranged to receive light from a laser. The modulator component may be arranged to achieve a modulated light signal modulated based on the driving voltage. The device may include a transmission line arranged to transfer the driving voltage between the driver component and the modulator component. The transmission line may not impedance matched to the driver component, the transmission line may have an impedance which is at least 20% lower than an output impedance of the driver component, and the transmission line may be impedance matched with respect to signal reflections to the modulator component.

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 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: Two low-speed electrical signals are first input to two electrical Return-to-Zero (RZ) converters to generate low-speed RZ electrical signals. After inverting one of the low-speed RZ electrical signals, the two low-speed RZ signals are then input to a dual-electrode optical modulator, e.g., a Mach-Zehnder interferometer. The dual-electrode optical modulator has a pair of electrodes driven with the pair of differential signals. This dual-electrode optical modulator has multiplexing as well as optical modulating capabilities. Within the dual-electrode optical modulator, each electrode is coupled to a different low-speed RZ electrical signal. The optical modulator also receives an optical beam from a traditional light source, e.g., a laser diode. As the electrodes of the dual-electrode modulator optically modulate independently, they effectively combine the low-speed RZ electrical signals into one Non-Return-To-Zero (NRZ) optical signal by time-division multiplexing the low-speed RZ electrical signals.

Abstract: A duobinary modulator and a method of modulating an optical signal so as to be coded in a duobinary manner, using optical modulating specifically adapted for this purpose is provided. Two input electrical signals are respectively input to two binary encoders. The binary encoders encode the input electrical signals and generate a pair of encoded binary signals which are then input to an analog amplifier. The analog amplifier amplifies the encoded binary signals and generates a pair of duobinary signals. Then, the duobinary signals are input to a dual-electrode modulator which modulates a pair of optical beams with the duobinary signals to generate a pair of modulated optical duobinary signals. Both modulated optical duobinary signals are then combined to generate the desired high-speed modulated optical duobinary signal.

Abstract: A duty cycle controller provides a uniform 50% duty cycle in a 2:1 digital multiplexer without an upper operating frequency limit. The multiplexer uses a comparator to generate interleaving signals by comparing a clock signal to a comparator set point. A feedback loop includes a bandpass filter, a power detector and an integrator, connected in series between the multiplexer output and the comparator. The bandpass filter passes components of the multiplexed output signal with a frequency substantially equal to the main clock frequency of the multiplexer. Signal components at that frequency are a second harmonic of the fundamental frequency of the multiplexed signal and therefore will not be present in the multiplexed signal if its duty cycle is exactly 50%. The power level of those frequency components is integrated over a suitable time period and the integrated signal is used to adjust the set point of the comparator.

Abstract: In an ultra high speed optical communications system, the clock signal from a data stream in NRZ format is recovered using an inexpensive, low Q filter. Resulting clock jitter is reduced with a clock divider which lowers the speed of the signal by 1/n, where n is a an integer. The divided clock signal is filtered again by a low frequency high Q filter. This invention eliminates the need for a costly high frequency high Q filter, while providing a divided down clock for data de-multiplexing. At the lower speed, an inexpensive D flip flop is used with the divided down clock for data recovery.

Abstract: The specification describes a comparator circuit especially designed for high speed applications such as lightwave systems. The comparator is compensated for offset voltages due to current leakage and other variations in the IC components.

Abstract: A transversal equalizer is realized by employing variable gain and delay in the amplification branches of a traveling wave amplifier. Specifically, by adjusting the gain and delay in each branch, the traveling wave type transversal equalizer may be adjusted to having a complementary frequency response in order to compensate for linear channel gain and phase ripples. This approach permits the transversal equalizer to be designed without the use of resistive splitter and combiner networks and, therefore, without the use of high gain amplifiers. Without such amplifiers, splitters and combiners, the smaller physical size, which is afforded thereby, allows the transversal equalizer to be easily assembled as a hybrid integrated circuit.