Libo Cai

Analysis of photonic frequency upconversion for radio-on-fiber applications using two-pump four-wave mixing in semiconductor optical amplifiers

A novel scheme of photonic frequency conversion based on two-pump four-wave mixing in a semiconductor optical amplifier is proposed. Characterized by its wide conversion range, the proposed scheme has the potential to generate millimeter waves at much higher frequency and convert several signal channels simultaneously. The system performance is analyzed through a numerical model, and the effect of the pump-signal pulse parameters on the conversion efficiency is discussed.

Numerical modeling and experimental testing of reflective semiconductor optical amplifier (RSOA) with modulation bandwidth optimization

A numerical model for RSOA including spatial variations of carrier density and ASE noise, is established and validated via experimental tests. Performance of RSOA with different cross-sectional areas of active region is investigated in the simulations. Reducing the cross-sectional area can increase its modulation bandwidth.

Polarization independent 4-stage OTDM multiplexer using plated GRIN lens

In this paper, a 4-stage optical time domain multiplexing (OTDM) multiplexer based on plated graded index (GRIN) lens is proposed and experimentally demonstrated. A 10Gbit/s return-to-zero (RZ) signal is upgraded to 160Gbit/s. The time-domain accuracy of the multiplexer is evaluated by analyzing the multiplexed 160Gbit/s signal. Experimental results validate the stability of the optical multiplexing behavior and the polarization insensitivity of the proposed multiplexer. The results also show the advantages of our OTDM multiplexer such as the flexible output signal speeds at the output of different stages, the low insertion loss and the temperature and wavelength stability.

Study on the time delay error for 160 Gbit/s multiplexer

By using thin membrane plating technology in collimating lens, we successfully manufacture a 16×10Gbit/s multiplexer basing on the combination of fiber and space structure method. The multiplexer is flexible according to your practical need that can output 20, 40, 80, or 160Gbit/s signal. For 20, 40, 80 or 160Gbit/s multiplexer, insertion loss is 3.5dB, 7dB, 10.5dB and 14dB respectively. The low insertion loss provides maximum transmission power. It also has such features: high time-delay accuracy, polarization insensitivity, broadband, very short coherence length, high time-delay accuracy, and excellent temperature stability. It differs from the structure of general Mach-Zehnder interferometer. It has the structure of Michelson interferometer.

High efficiency 160 Gb/s all-optical wavelength converter based on terahertz optical asymmetric demultiplexer with quantum dot semiconductor optical amplifier

Proposed in this paper is a high efficient 160Gb/s all-optical wavelength converter based on terahertz optical asymmetric demultiplexer with quantum dot Semiconductor optical amplifier (QDSOA -TOAD). The performance of the wavelength converter under various operating conditions, such as different injected current densities, input pulse widths and input control pulse energies, is analyzed in terms of contrast ratio (CR) through numerical simulations. With the properly chosen parameters, a wavelength-converted signal with CR over 19.48 can be obtained.

Parameter optimization of nonlinear SOA in an SOA-MZI packet-level self-synchronization scheme

Introduced in this paper is an experimental system of packet-level self-synchronization using semiconductor optical amplifier based Mach-Zehnder interferometer (SOA-MZI). The function of SOA-MZI in the system is analyzed, as well as the relationship among key parameters of various components. A tunable optical delay line is used for the adjustment of phase difference. It reveals that SOA-MZI is an effective way to extract self-synchronization clock in both experiments and practical applications.

Frequency up-conversion and mm-wave generation based on dual-pump FWM in SOAs

In this paper, a novel scheme utilizing the dual-pump FWM in SOA is proposed for the frequency up-conversion and the generation of mm-wave. Characterized by its large conversion range, the proposed scheme has the potential to generate mm-wave at much higher frequency and to convert several signal channels simultaneously. Performance of the system is analyzed through a numerical model and the impact of the pumps power on the conversion efficiency is discussed.

Performance analysis of all optical XOR gate using quantum dot semiconductor optical amplifier-based Mach-Zehnder interferometer

Based on rate equations for carrier density in the active region of the QDSOA, the performance of a XOR gate using a quantum-dot semiconductor optical amplifier- based Mach-Zehnder interferometer (QDSOA-MZI) is analyzed in terms of Q factor through numerical simulations. The control pulse energy, the pulse width and the carrier capture time from the wetting layer into the dots are examined, which prove to be relevant to the Q factor. Our numerical results show that at 160Gb/s a high quality output signal with a Q factor over 5.9dB can be achieved.

Study on the time delay error for 160Gbit/s multiplexer

A 16×10Gbit/s multiplexer basing on the combination of fiber and space structure method is manufactured. The time-delay error of the multiplexer is only 0.007ps, and this accuracy meets the demand of 160Gbit/s transmission. It differs from the structure of general Mach-Zehnder interferometer. It has the structure of Michelson interferometer. The low insertion loss provides maximum transmission power. It also has such features: high time-delay accuracy, polarization insensitivity, broadband, very short coherence length, high time-delay accuracy, and excellent temperature stability.