Photonic generation of ultrawideband signals using a delay interferometer

Abstract

We demonstrate a novel scheme to generate ultrawideband (UWB) monocycle and doublet pulses by inputting a dark return-to-zero (RZ) signal into a delay interferometer (DI), which accords with the general features in future applied UWB system, namely, single optical source input, simple configuration and passive device. The two polarized interferential beams have a time delay and a phase difference when they propagate through the DI. By adjusting polarization controllers (PCs), the total phase difference, i.e., the sum of the relative opticalphase difference between two orthogonally polarized components caused by PCs and the optical-phase shift due to birefringence of the polarization-maintaining fiber (PMF), the orientation angle of the polarization beamsplitter (PBS) relative to the two axes of the PMF are able to be changed and controlled. When the appropriate conditions are met, UWB monocycle and doublet pulses are generated conveniently.

Tunable optical delay line based on integrated grating-assisted contradirectional couplers

“…Optical delay lines have wide applications in optical communication and microwave photonics systems [1][2][3][4][5][6][7][8]. In optical communication, the main functions of optical delay lines cover signal synchronization, optical buffers, time-division multiplexing, and so forth.…”