Emulation of Integrated High-Bandwidth Photonic AWG Using Low-Speed Electronics

For increasing the data rates in digital communication networks, high-speed signal generation is required. To generate these high-speed signals, electronics-based arbitrary waveform generators (AWGs) are the key components. However, most of the commercially available high-speed electronic AWGs are subject to linearity and resolution limitations. Photonics-based AWG, instead, might offer high bandwidth with better resolution and phase noise. Several photonic techniques have been proposed in recent years but with increased system complexity and limited dynamic range. We have recently proposed a photonics based architecture for high-speed arbitrary waveform generation using low-speed electronics, which is based on optical Nyquist pulse sequences and time-domain interleaving to obtain high-quality waveforms. Within this system, a single laser source is split into N branches. A Nyquist pulse sequence is generated by an integrated modulator driven by a single electrical sinusoidal frequency in each branch. Subsequently, they are modulated and multiplexed to obtain the targeted waveforms. The time delay between the pulse sequences is realized by a simple electrical phase shift of the sinusoidal driving signal. Here, a theoretical validation for the N channel system is presented along with simulation and experimental results for a three-branch photonic AWG. Using an integrated silicon Mach-Zehnder modulator saw-tooths, sinusoidal and some bandwidth-limited analog waveforms are generated. With available 100 GHz integrated modulators, the maximum possible sampling rate of 300 GS/s can be achieved. The mathematical proof validates that this simple concept can generate bandwidth limited user-defined waveforms with very high precision.