We propose and experimentally demonstrate a cable television monitoring system based on a linear-cavity fiber laser and fiber Bragg grating (FBG) sensors. The linear-cavity fiber laser comprises a hybrid amplifier with an erbium-doped fiber amplifier and a semiconductor optical amplifier, a fiber loop mirror with a polarization controller and an optical coupler as a cavity mirror, and the FBG sensors acting as another cavity mirrors. Experimental results showed the feasibility of the monitoring system with sufficient of signal-to-noise ratio over 30 dB and stable output power, and the link of cable television signals on fiber link can monitored in real time. Excellent performances of carrier-to-noise ratio after long-distance transmission are obtained for cable television applications.
KEYWORDS: Modulation, Radio over Fiber, Fiber to the x, Single mode fibers, Eye, Composites, Single sideband modulation, Networks, Optical amplifiers, Light sources
A potentially cost-effective radio-over-fiber (ROF)/fiber-to-the-X (FTTX)/CATV hybrid three-band transport system
based on direct modulation of a distributed feedback laser diode (DFB LD) with multi-wavelength output characteristic
is proposed and experimentally demonstrated. Directly modulated radio-frequency (RF) (1.25Gbps/6GHz), externally
remodulated baseband (BB) (622 Mbps), and externally remodulated CATV (channels 2-78) signals are successfully
transmitted simultaneously. Over an 80-km single-mode fiber (SMF) transmission, low bit error rate (BER) and clear eye
diagram were achieved for ROF and FTTX applications; and good performances of carrier-to-noise ratio (CNR),
composite second-order (CSO) and composite triple beat (CTB) were obtained for CATV signals. Since our proposed
systems use only a directly modulated DFB LD to achieve multi-wavelength transmission, it reveals an outstanding one
with simpler and more economic advantages.
An actively mode-locked fiber ring laser for generating wavelength-tunable optical pulses is demonstrated. An Er-Yb
doped waveguide amplifier is used as an optical amplifier, and a Fabry-Perot laser diode is used as a modulator in the
fiber laser. Moreover, we add a variable optical delay line to control the cavity length for maintaining a constant
repetition frequency and pulsewidth at different wavelengths. The optical side-mode-suppression-ratio is better than 33.5
dB over the wavelength-tunable range of 46 nm.
A system to generate wavelength-tunable optical short pulses with a constant repetition frequency and pulse width by a gain-switched Fabry-Pérot laser diode (FPLD) in a self-injection scheme is demonstrated. A variable optical delay line is used to control the self-injection scheme to maintain a constant repetition frequency and pulse width at different wavelengths. The optical sidemode suppression ratio (SMSR) of this system is better than 33 dB over the wavelength-tunable range of 33 nm.
We demonstrate tunable single- and dual-wavelength fiber ring lasers using a compact Er-Yb doped waveguide amplifier. In the single-wavelength operation, a signal-to-noise ratio higher than 63 dB and an output power maintaining around 11 dBm in the operation range over 50 nm (from 1529.1 to 1579.43 nm) are achieved. In the dual-wavelength operation, lasing wavelengths with wavelength separation from 51.73 to 6.2 nm are demonstrated.
A fiber Bragg grating (FBG) sensor system using a fiber ring laser with a hybrid amplifier is proposed and demonstrated. The hybrid amplifier comprises an erbium doped waveguide amplifier and a semiconductor optical amplifier. The experiment shows that such the hybrid amplifier has a high amplifier spontaneous emission power and gain spectrum. Moreover, this fiber ring laser can provide a stable multiwavelength output with an optical signal-to-noise ratio over 50 dB even if the FBGs are located at a 25 km remote sensing position.
A novel wavelength-tunable add-drop multiplexer (ADM) using fiber Fabry-Pérot tunable filters (FFP-TFs) for the bidirectional wavelength division multiplexing (WDM) network is proposed and demonstrated. The wide tuning range, low loss, and low polarization dependence properties of the FFP-TFs are used for the ADM operation. The experimental results show that the wavelength tuning range of this wavelength-tunable ADM can be up to 40 nm. The bit-error-rate performance of the dropped and pass-through channels for a 2.5 Gbit/s system shows the feasibility of ADM.
We present a novel design of a two-layer Mach-Zehnder Interference switch using silicon-on-insulator integrated optical technology. According to the design, we can reduce the size of Mach-Zehnder Interference switches with six refractive index adjustment cases by Beam Propagation Method (BPM) simulation. Some cases of better switches are sorted by tuning the phase difference between the two paths of the Mach-Zehnder Interference refractive indexes of the rib bending waveguide. Such a device shows great potential in achieving coarse wavelength division routing devices.
Silicon will play a practical role in the future of optoelectronic devices. Silicon microelectronics fabrication techniques can be largely exploited to fabricate low-loss and high volume optical devices. In this paper, we report the concept and realization of new two-dimensional 1x16 and 1x32 array waveguide optical power splitters that offer the possibility of a free choice of the output power ration in silicon-on-insulator (SOI). The power splitters compose one dimensional multimode interference (MMI) optical power splitter and multi-layers coupler at wavelength at 155 (mu) m. According to the design, we can reduce the size of SOI power splitters waveguide without increasing propagation loss, efficiently. The results achieved show a remarkable improvement with respect to those of classical MMI power splitters.
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