Y. F. Wu

100 GHz ultra-wideband (UWB) fiber-to-the-antenna (FTTA) system for in-building and in-home networks

Fiber-to-the-antenna (FTTA) system can be a cost-effective technique for distributing high frequency signals from the head-end office to a number of remote antenna units via passive optical splitter and propagating through low-loss and low-cost optical fibers. Here, we experimentally demonstrate an optical ultra-wideband (UWB) - impulse radio (IR) FTTA system for in-building and in-home applications. The optical UWB-IR wireless link is operated in the W-band (75 GHz - 110 GHz) using our developed near-ballistic unitraveling-carrier photodiode based photonic transmitter (PT) and a 10 GHz mode-locked laser. 2.5 Gb/s UWB-IR FTTA systems with 1,024 high split-ratio and transmission over 300 m optical fiber are demonstrated using direct PT modulation.

Using OOK Modulation for Symmetric 40-Gb/s Long-Reach Time-Sharing Passive Optical Networks

Due to the requirement of broad bandwidth for next-generation access networks, present passive optical networks (PONs) will be upgraded to 40 Gb/s or higher data rate PONs. Hence, we propose and experimentally demonstrate a simple and efficient scheme to achieve a symmetric 40-Gb/s long-reach (LR) time-division-multiplexed PON by using four wavelength-division-multiplexed 10-Gb/s external on-off keying format channels to serve as the optical transmitter for downstream and upstream traffic simultaneously. Moreover, the system performance of LR transmission and split ratio have also been analyzed and discussed without dispersion compensation.

Using four wavelength-multiplexed self-seeding Fabry-Perot lasers for 10 Gbps upstream traffic in TDM-PON

In this paper, we propose and experimentally investigate a simple self-injection Fabry-Perot laser scheme on each optical network unit (ONU) for 10 Gbps TDM passive optical networks (PONs). Based on the proposed four wavelength-multiplexed 2.5 Gbps lasers, the 10 Gbps uplink traffic can be achieved at a cost-effective way. The network architecture and performance have also been analyzed and discussed.

Performance of Long-Reach Passive Access Networks Using Injection-Locked Fabry–Perot Laser Diodes With Finite Front-Facet Reflectivities

In this study, we use the injection-locked Fabry-Perot laser diodes (FP-LDs) with front-facet reflectivities of 10% and 35% respectively, as colorless optical networking unit (ONU) in long-reach passive optical networks (LR-PONs). Here, the injection-locked FP-LD is directly modulated at 2.5 Gbit/s on-off keying (OOK) and 10 Gbit/s orthogonal-frequency-division-multiplexing (OFDM) modulations for upstream traffic transmission over 60 km of single-mode fiber (SMF). Different operating parameters for the injection-locked FP-LD to achieve higher data rate transmission are reported.

A simple self-restored fiber Bragg grating (FBG)-based passive sensing ring network

In this investigation, we propose and experimentally investigate a simple self-restored fiber Bragg grating (FBG)-based sensor ring system. This proposed multi-ring passive sensing architecture does not require active components in the network. In this experiment, the network survivability and capacity for the multi-point sensor systems are also enhanced. Besides, the tunable laser source (TLS) is adopted in a central office (CO) for FBG sensing. The survivability of an eight-point FBG sensor is examined and analyzed. It is cost effective since the sensing system is entirely centralized in the CO. Experimental results show that the proposed system can enhance the reliability of the FBG sensing network for large-scale and multi-point architecture.

Employing external injection-locked Fabry-Perot laser scheme for mm-wave generation

We propose and experimentally investigate a 170 GHz band millimeter-wave source employing an external dual-mode-locked Fabry-Perot laser diode (FP-LD) with a 1.38 nm mode-spacing. Two continuous-wave (CW) lights are aligned to inject the corresponding modes of FP-LD to generate dual-beat-mode output. The proposed dual-mode laser is not only stable, but also has single-longitudinal-mode (SLM) output characteristics. Moreover, the relationship between two external-injected wavelengths is also analyzed for the dual-wavelength output.

Tunable Dual-Wavelength Fiber Laser Using Optical-Injection Fabry–PÉrot Laser

In this investigation, we propose and experimentally demonstrate a dual-wavelength fiber laser based on a self-injected Fabry–PÉrot laser diode and an erbium-doped fiber. The dual-wavelength tuning range is 39.49 nm, from 1526.27 to 1565.76 nm, and the mode spacing of the dual-wavelength can be tuned from 1.32 to 39.49 nm. In addition, the output power difference of the dual-wavelength can be controlled and smaller than 1 dB.

Wavelength-Tunable Laser for Signal Remodulation in WDM Access Networks Using DPSK Downlink and OOK Uplink

In this investigation, a simple wavelength-tunable laser based on a Fabry-Perot laser diode (FP-LD) and an erbium-doped fiber amplifier to serve as a downlink signal in a colorless wavelength-division-multiplexed passive optical network (PON) is proposed and experimentally demonstrated. The tuning range of the proposed laser is between 1529.48 and 1560.72 nm, and the output performance of proposed laser is discussed. Colorless operation is implemented by using an FP-LD and a reflective semiconductor optical amplifier in each optical network unit for uplink signal remodulation, respectively. In addition, error-free data signal remodulation using 10-Gb/s downlink differential phase-shift keying and 2.5-Gb/s uplink on-off keying is achieved in a 25-km reach PON.

Rayleigh Backscattering Circumvention in Ring-Based Access Network Using RSOA-ONU

We propose and demonstrate a Rayleigh backscattering (RB) interferometric beat noise circumvention architecture for the ring-based wavelength-division-multiplexed (WDM) access networks. RB can be significantly avoided since the RB and the upstream signal are traveling in opposite directions. We also analyze the performance of the proposed scheme for upgrading to 40 Gb/s and the influence of wavelength-drift at the remote node (RN).

Dual-reflected-structure erbium-doped fiber laser in single-longitudinal-mode for wavelength-tuning

In this work, we propose and demonstrate a dual-reflected-structure erbium-doped fiber (EDF) laser with a linear cavity using a passive saturable-absorbor-based (SAB) filter to achieve single-longitudinal-mode (SLM) lasing. Here, we can observe the wavelength tuning range between 1530.0 and 1562.0 nm with the output powers of −13.7 to −7.6 dBm and optical signal to noise ratios (OSNRs) of 35.4 and 47.9 dB/0.05 nm, respectively. Moreover, when the lasing wavelength is tuned to the longer wavelength gradually, the obtained output power and SNR increase. This is because the Er+ gain can be suppressed and moves to the longer wavelength via the proposed fiber laser structure. In addition, the output stability of the proposed laser has also been analyzed and studied.