A resonator-based time-stretch oscilloscope with variable magnification and time-aperture

We present a resonator-based approach to time-stretch electrical signals with variable temporal magnification up to M=100 and time-aperture up to 800 ps. In contrast to the conventional linear time-stretch setups with fixed magnification [Chou, J. ; Boyraz, O. ; Solli, D. ; Jalali, B.: In: Applied Physics Letters 91 (2007)] an optical pulse of an broadband laser source Dl will be prechirped in a first dispersive fiber. This prechirped pulse will be modulated in an electro-optical modulator. The modulated optical pulse couples via a beam-combiner into a fiber-based resonator. In this resonator, a dispersive and Raman-active fiber as well as a Raman-amplifier are placed. The fiber stretches the pulse and amplifies the signal at the same time. This concept comprises a measurement s ystem with short fibers and high possible stretch-factors. After every resonator round-trip, an adequate part of the power is coupled out using a switch and detected by a fast photo-diode. The achievable magnification M depends on the number of round-trips N. Hence, this approach provides different magnification factors with only one configuration: A time-stretch setup with variable temporal magnification.