Low-Complexity TOAD-Based All-Optical Sampling Gate With Ultralow Switching Energy and High Linearity

Abstract

We present experimentally a low-complexity ultralow switching energy and highlinearity all-optical sampling gate based on a terahertz optical asymmetric demultiplexer, constructed by placing a polarization-insensitive multiple-quantum-well semiconductor optical amplifier (PI-MQW-SOA) asymmetrically within a fiber loop mirror. Using a picosecond pulse train as the trigger clock, we analyze, in detail, the influence of the sampling pulse power and the offset of the PI-MQW-SOA from the loop midpoint on the shape, width, and amplitude of the sampling window, respectively. Furthermore, the switching energy and linearity of this sampling gate under different widths of sampling windows are specifically investigated. Results demonstrate that our sampling gate possesses a switching energy as low as 25 fJ and a high linearity above 0.99.

Optical gating width variability using electrode parasitic capacitance

“…An optical sampling technique is effective to measure waveforms to assess the quality of high-speed modulation signals. An optical sampling gate [1,2,3] with short gating width and high extinction ratio is required for an OPM with high temporal resolution and signal-to-noise ratio. The electro-absorption modulator (EAM) based on cross absorption modulation (XAM) is a leading candidate for a compact optical sampling gate with high cost efficiency [4,5,6,7,8].…”

Study of all-optical sampling using a semiconductor optical amplifier

“…On the one hand, the SOA can achieve online amplification in the optical communication link to make up line loss; on the other hand, it has advantages of high nonlinear coefficient, compact structure, low power consumption, and ease to integrate. In particular, the SOA can produce many optical nonlinear effects, such as cross phase modulation (XPM) [1,2], cross gain modulation (XGM) [3,4], four-wave mixing (FWM) [5,6], and nonlinear polarization potation (NPR) [7,8], which can achieve wavelength conversion, optical switch, optical buffer, and all-optical sampling in the signal processing [9][10][11][12]. Compared with other nonlinear effects of the SOA, NPR is applied to more various aspects due to that it is high-speed and easy to implement, and can also achieve a positive and inverted beam at the same time.…”