Fang-Ming Wu

1.1-Gb/s White-LED-Based Visible Light Communication Employing Carrier-Less Amplitude and Phase Modulation

We demonstrate 1.1-Gb/s visible light communication (VLC) employing carrier-less amplitude and phase modulation (CAP) and a commercially available phosphorescent white light emitting diode (LED). Optical blue filtering, precompensation, and decision feedback equalization are used to compensate the frequency response of the phosphor-based white LED. Various modulation orders of CAP signals are investigated to maximize the capacity of the VLC system. The record data rate of 1.1 Gb/s with the bit error rate performance below the FEC limit of 10-3 is successfully achieved >; 23-cm air-transmission via a 220-MBaud 32-CAP signal.

Polarization Characteristics of Quantum-Dot Vertical-Cavity Surface-Emitting Laser With Light Injection

This investigation explores experimentally the optical characteristics of long-wavelength quantum-dot vertical-cavity surface-emitting lasers (QD VCSELs). The InAs QD VCSEL, fabricated on a GaAs substrate, is grown by molecular beam epitaxy with fully doped distributed Bragg reflectors. The optical characteristics of QD VCSEL without and with light injection are studied in detail. The QD VCSEL has the potential to be used in all-optical signal processing systems.

RF phase shifter using a distributed feedback laser in microwave transport systems.

This work experimentally demonstrates the efficacy of a radio-frequency phase shifter using a distributed feedback laser in a microwave transport system. Phase shifts of about 101 degrees are obtained at 8.75 GHz. The proposed phase shifter can amplify microwave signals and thereby improve transmission performance. Additionally, a similar single sideband modulation can be generated by the phase shifter. Experimental results indicate that the proposed phase shifter can be used in future long-distance microwave transport systems and all optical inverters.

Transmission distance improvement employing simple 60GHz radio-over-fiber system with beat noise mitigation

We propose a simple 60GHz RoF system using a single-electrode MZM with transmission distance improvement from 3km to 10km. With beat noise mitigation algorithm, SNR can be improved by up to 5.5dB.

SOA-based fiber ring laser use in a photonic radio-frequency phase shifter

This investigation demonstrates the feasibility of a semiconductor optical amplifier (SOA)—based fiber ring laser use in a photonic radio-frequency (RF) phase shifter. Experimental results indicate that a fiber ring laser can successfully replace an external pump laser in a photonic RF phase shifter. The RF phase shifter can be turned by adjusting the power of the fiber ring laser.

Electrically controlled phase shifter using semiconductor laser in optical single sideband system

This investigation experimentally explores a microwave phase shifter using a semiconductor laser in an optical single sideband system. The operational bandwidth from 12 to 20 GHz is achieved by adjusting the bias current.

Electrically and Continuously Tunable Optical Delay Line Based on a Semiconductor Laser

This investigation experimentally demonstrates the feasibility of the electrically and continuously tunable optical delay line using a semiconductor laser. The time delays for a 10 Gbps data signal are electrically delayed by adjusting the bias current of laser, and the maximum delay is approximately 41 ps. We also measure the bit error rate against the receiver power by various bias currents and wavelength detuning (Δλ). Measurements are made to verify the feasibility to use in optical communication systems.

Tunable slow light in quantum well vertical-cavity surface-emitting laser at 40 GHz

This investigation experimentally demonstrates tunable slow light in a quantum well vertical-cavity surface-emitting laser at 40 GHz. Tunable optical delays are achieved by adjusting the bias current and wavelength detuning.

Interference Mitigation in Indoor LEDs-Based Visible Light Communication Systems Employing Alamouti STBC with CAP Modulation

This work employs Alamouti space-time block coding to mitigate interference in indoor VLC systems, while the usage of multiple LEDs to cover wider range could induce the multipath interference. Under the interference between two 2-m apart LEDs, 150-Mbps 4-CAP signals can achieve the BER of <2×10−3 over 3.2-m air transmission.

Ultra-high capacity 60-GHz fiber-wireless systems

Several digital signal processing techniques and methods have been demonstrated to solve many technical challenges of 60-GHz fiber-wireless system. Using these solutions, we have experimentally demonstrated ultra-high capacity RoF systems operating at up to 50Gb/s.