An alternative light source for coherent anti-Stokes Raman scattering (CARS) microspectroscopy based on red-shifted solitons in a polarization-maintaining photonic crystal fiber (PM-PCF) is experimentally demonstrated. By coupling femtosecond pulses into the anomalous dispersion region of the fundamental mode of a PM-PCF along the slow and fast axes, the red-shifted solitons generated can be used as the Stokes beams when the pump pulses are chosen as the pump beams. Through the process of red-shift, the frequency differences of the pump-Stokes beams are tunable in the ranges of 0 to 4068 cm−1 and 0 to 4594 cm−1, respectively. Moreover, because of the well maintained polarization states of the pump and Stokes beams and the high output powers of the solitons, CARS microspectroscopy using the proposed source will have a high signal-to-noise ratio and short data acquisition time. CARS microspectroscopy based on the proposed all-fiber light source can be used for studying a wide range of vibrational Raman spectra.
We propose a scheme for the real-time optical sampling of a multicast signal based on the parametric process. The linearly chirped and time-broadened pulses are used instead of the traditional mode-locked sampling pulses. The amount of signal copies or the rate of sampling train can be efficiently reduced by the chirped pulses while keeping a high-equivalent sampling rate. Simulation results show that the equivalent sampling rate of 120 GSa/s can be obtained by using only a sampling source of 10 GHz together with three signal copies. This scheme can efficiently improve the sampling rate in the real-time optical sampling and reduce the requirement on electronic devices for signal processing.
Optical receiver of high speed and high sensitivity is indispensable for long distance fiber-optic communication systems
of transmitting rate up to Gb/s. In recent years, OEIC (Optoelectronic Integrated Circuits) optical receiver has attracted
more and more attention for its advantages over conventional optical receiver such as minimized parasitics, lower cost,
higher reliability and compact size. In this paper, design of preamplifier for InP-based PIN/HBT OEIC optical receiver
with share layer structure was presented. As a basis for design of preamplifier, HBT large signal model (GP model)
was investigated and model parameters were extracted and optimized. The extracted GP model shows a good agreement
with measured characteristics of HBT fabricated. Based on this GP model, the preamplifier was designed and fabricated
which exhibits good high-frequency characteristics of −3dB bandwidth is up to 2.0 GHz.