A compact optical sampling measurement system using mode-locked laser-diode modules

Evolution of Optical Sampling

“…Independently on the sampling technique, the optical sampling operation requires a nonlinear interaction between the signal to be resolved and an ultra-short pulse train that act as sampling signal. Such nonlinear process can be generated in different nonlinear elements as highly non linear fiber (HNLF) (Malacarne et al, 2007;Watanabe et al, 2004;Schmidt et al, 2002a), nonlinear crystals and waveguides Takara et al, 1996a;Kawanishi et al, 2001) or semiconductor devices (Maguire et al, 2005;Shirane et al, 2000). Fibers, crystals and waveguides may enable ultra-fast dynamics and high efficiency, while semiconductor devices could reduce the power consumption.…”

Optical waveform monitoring based on a free-running mode-locked femtosecond fibre laser and four-wave mixing in a highly nonlinear fibre

“…These include the second−order susceptibil− ity c 2 in nonlinear crystals (e.g., KTiOPO 4 (KTP) [14,15] and periodically poled LiNbO 3 (PPLN) crystals [4,5]) and the third−order susceptibility c 3 (e.g., cross−phase modulation and four−wave mixing) in nonlinear optical fibres [1,2,16], semiconductor optical amplifiers (SOAs) [3,17], and silicon nanowire [12] or chalcogenide planar waveguide [13], respec− tively. Nevertheless, those schemes can have their individual advantages and respective drawbacks in terms of operational speed, wavelength range, manufacturing cost, complexity and physical size of the resulting optical waveform samplers (also called sampling gates).…”

“…Moreover, the optical front−end of such an oscilloscope is based on an ultrafast photodetector which, in turn, leads to a much poorer optical receiver sensitivity than that based on a low−speed photodetector (e.g., £ 100 MHz). The last ap− proach is to use a streak camera which, however, has a low sensitivity at the wavelength around 1550 nm [1][2][3], and, therefore, precludes the monitoring of optical eye diagrams. Consequently, a new type of optical waveform measurement systems needs to be developed, which should use the all−op− tical waveform sampling based on ultrafast optical nonline− arities to ensure a very wide measurement bandwidth up to several hundreds of gigahertz or a few terahertz [1,2].…”

“…At present, all−optical waveform sampling is normally im− plemented by exploiting the nonlinear optical effects in opti− cal media such as optical fibres [1,2,7], waveguides [3,12,13] and crystals [4,5]. These include the second−order susceptibil− ity c 2 in nonlinear crystals (e.g., KTiOPO 4 (KTP) [14,15] and periodically poled LiNbO 3 (PPLN) crystals [4,5]) and the third−order susceptibility c 3 (e.g., cross−phase modulation and four−wave mixing) in nonlinear optical fibres [1,2,16], semiconductor optical amplifiers (SOAs) [3,17], and silicon nanowire [12] or chalcogenide planar waveguide [13], respec− tively.…”

The Integration of the All-Optical Analog-to-Digital Converter by Use of Self-Frequency Shifting in Fiber and a Pulse-Shaping Technique

“…In the most of previously proposed optical A/D conversion system, quantization and coding are realized by electrical processing technique after the optical sampling process [2][3][4]. Because of the difficulty in realizing optical multilevel thresholding, which is essential to optical quantization, there are few investigations of the optical quantization and optical coding technique [5][6][7].…”