Abstract: Systems and methods for determining the envelope of a modulated signal using high bandwidth and low bandwidth samples of a hybrid signal. The hybrid signal is obtained by mixing the modulated signal with its carrier signal. The systems and methods of the present disclosure may be suitable for equivalent-time or real-time oscilloscopes.

Abstract: Systems and methods for determining the envelope of a modulated signal using high bandwidth and low bandwidth samples of a hybrid signal. The hybrid signal is obtained by mixing the modulated signal with its carrier signal. The systems and methods of the present disclosure may be suitable for equivalent-time or real-time oscilloscopes.

Abstract: This invention relates to a method and apparatus for measuring the phase change of an output optical signal from a device. In one embodiment an input optical signal is split into first and second optical signals, and the first optical signal is passed through the device while applying an external stimulus to the device, to produce an output optical signal having a phase shift. The carrier frequency of the second optical signal is changed, and the output optical signal and the changed second optical signal are then combined. The combined signal is detected in accordance with the external stimulus applied to the device, and the phase change of the output signal of the device is measured as a function of the external stimulus applied to the device.

Abstract: A Mach-Zehnder optical modulator in which the chirp parameter can be varied by adjusting the optical power splitting ratio between the two arms of the interferometer. The modulating voltage is supplied to a single arm or alternatively to both arms in a push-pull configuration. For an appropriate power splitting ratio negative chirp is achieved with approximately equal push-pull modulating drive voltage. This results in optimum distance and bit rate characteristics with low drive power.