Interferometer-based chemical sensor on chip with enhanced responsivity and low-cost interrogation.

We report experimental results of an interferometric chemical sensor integrated on a silicon chip. The sensor measures refractive index variations of the liquid that contacts exposed spiraled silicon waveguides on one branch of a Mach-Zehnder interferometer. The system requires neither laser tuning nor spectral analysis, but a laser at a fixed wavelength, and a demodulation architecture that includes an internal phase modulator and a real-time processing algorithm based on multitone mixing. Two devices are compared in terms of sensitivity and noise, one at 1550 nm wavelength and TE polarization, and an optimized device at 1310 nm and TM polarization, which shows 3 times higher sensitivity and a limit of detection of 2.24·10-7 RIU.

A wavelength-preserving photonic integrated regenerator for NRZ and RZ signals.

This paper presents a novel Indium Phosphide based photonic integrated circuit (PIC) for all-optical regeneration of both nonreturn-to-zero (NRZ) and return-to-zero (RZ) on-off-keying (OOK) signals. The PIC exploits cross gain compression in two semiconductor optical amplifiers to simultaneously obtain a wavelength-preserved and reshaped copy, and a wavelength-converted yet inverted copy of the input signal. Regeneration of 10 Gb/s signals on multiple wavelengths is demonstrated, showing a Q-factor improvement from 1.5 to 4 for NRZ-OOK signals and from 2.3 to 3.6 for RZ-OOK signals, and a BER improvement up to 1.5 decades.