Two-way lightwave subcarrier transmission system.

This Letter proposes and demonstrates a two-way lightwave subcarrier transmission system employing interleavers to deliver intensity-modulated CATV/phase-modulated RoF/intensity-remodulated 16-QAM-OFDM signals over two 20 km SMF links. To the best of our knowledge, it is the first time that interleavers have been employed in two-way lightwave subcarrier transmission systems. The downstream light is successfully intensity-remodulated with a 16-QAM-OFDM signal for uplink transmission. We obtained excellent performance from the CNR/CSO/CTB/BER for CATV/RoF/16-QAM-OFDM signal transmissions. The proposed systems offer impressive performance features to deliver hybrid CATV/RoF/16-QAM-OFDM signals.

A 10-Gbps optical WiMAX transport system.

A 10-Gbps optical worldwide interoperability for microwave access (WiMAX) transport system employing vertical cavity surface emitting laser (VCSEL) and spatial light modulator (SLM) with 16-quadrature amplitude modulation (QAM)-orthogonal frequency-division multiplexing (OFDM) modulating signal is proposed. With the assistance of equalizer and low noise amplifier (LNA) at the receiving site, good bit error rate (BER) performance, clear constellation map, and clear eye diagram are achieved in the proposed systems. An optical WiMAX transport system, transmitting 16-QAM-OFDM signal over a 6-m free-space link, with a data rate of 10 Gbps is successfully demonstrated. Such a 10-Gbps optical WiMAX transport system would be attractive for providing services including Internet and telecommunication services. Our proposed system is suitable for the free-space lightwave transport system in visible light communication (VLC) application.

A multiple-input-multiple-output visible light communication system based on VCSELs and spatial light modulators.

A multiple-input-multiple-output (MIMO) visible light communication (VLC) system employing vertical cavity surface emitting laser (VCSEL) and spatial light modulators (SLMs) with 16-quadrature amplitude modulation (QAM)-orthogonal frequency-division multiplexing (OFDM) modulating signal is proposed and experimentally demonstrated. The transmission capacity of system is significantly increased by space-division demultiplexing scheme. With the assistance of low noise amplifier (LNA) and data comparator, good bit error rate (BER) performance, clear constellation map, and clear eye diagram are achieved for each optical channel. Such a MIMO VLC system would be attractive for providing services including data and telecommunication services. Our proposed system is suitably applicable to the lightwave communication system in wireless transmission.

Optical free-space wavelength-division-multiplexing transport system.

An optical free-space wavelength-division-multiplexing (WDM) transport system employing vertical cavity surface emitting lasers and spatial light modulators with 16-quadrature amplitude modulation orthogonal frequency-division multiplexing modulating signals over a 17.5 m free-space link is proposed and demonstrated. With the help of a low-noise amplifier and data comparator, good bit error rate performance is obtained for each optical channel. Such an optical free-space WDM transport system would be attractive for providing services including data and telecommunication services.

Hybrid lightwave subcarrier CATV/16-QAM/16-QAM OFDM transmission system.

A hybrid lightwave subcarrier CATV/16-QAM/16-QAM orthogonal frequency-division multiplexing (OFDM) transmission system employing light injection/optoelectronic feedback techniques and photonic crystal fiber (PCF) is proposed and demonstrated. Good performance of carrier-to-noise ratio (CNR), composite second order, and composite triple beat were obtained for the CATV band, and high CNR and low bit error rate values were achieved for the 16-QAM and 16-QAM OFDM bands over a combination of 80 km single-mode fiber (SMF) and 2.86 km PCF transport.

Full-duplex lightwave transport systems based on long-haul SMF and optical free-space transmissions.

A full-duplex lightwave transport system employing wavelength-division-multiplexing (WDM) and optical add-drop multiplexing techniques, as well as optical free-space transmission scheme is proposed and experimentally demonstrated. Over an 80-km single-mode fiber (SMF) and 2.4 m optical free-space transmissions, impressive bit error rate (BER) performance is obtained for long-haul fiber link and finite free-space transmission distance. Such a full-duplex lightwave transport system based on long-haul SMF and optical free-space transmissions has been successfully demonstrated, which cannot only present its advancement in lightwave application, but also reveal its simplicity and convenience for the real implementation. Our proposed systems are suitable for the lightwave communication systems in wired and wireless transmissions.

Bidirectional 16-QAM OFDM in-building network over SMF and free-space VLC transport.

A bidirectional 16-quadrature amplitude modulation (QAM) orthogonal frequency-division multiplexing (OFDM) in-building network over 20 km single-mode fiber (SMF) and 15 m free-space visible light communication (VLC) transport is proposed and experimentally demonstrated. Good bit error rate performances and clear constellation maps are obtained for 16-QAM OFDM applications in our proposed in-building networks.

Bidirectional phase-modulated hybrid cable television/radio-over-fiber lightwave transport systems.

A bidirectional phase-modulated hybrid cable television/radio-over-fiber lightwave transport system employing fiber Bragg grating tilt filter as a phase modulation-to-intensity modulation conversion scheme is proposed and demonstrated. Impressive performances of carrier-to-noise ratio, composite second-order, composite triple-beat, and bit-error rate are obtained in our proposed systems over a combination of 40 km single-mode fiber-and 1.43 km photonic crystal fiber transmission.

10m/500 Mbps WDM visible light communication systems.

A wavelength-division-multiplexing (WDM) visible light communiction (VLC) system employing red and green laser pointer lasers (LPLs) with directly modulating data signals is proposed and experimentally demonstrated. With the assistance of preamplifier and adaptive filter at the receiving sites, low bit error rate (BER) at 10 m/500 Mbps operation is obtained for each wavelength. The use of preamplifier and adaptive filter offer significant improvements for free-space transmission performance. Improved performance of BER of <10(-9), as well as better and clear eye diagram were achieved in our proposed WDM VLC systems. LPL features create a new category of good performance with high-speed data rate, long transmission length (>5m), as well as easy handling and installation. This proposed WDM VLC system reveals a prominent one to present its advancement in simplicity and convenience to be installed.

A hybrid CATV/OFDM long-reach passive optical network architecture.

A hybrid CATV/OFDM long-reach PON architecture is proposed and experimentally demonstrated. By multiplexing the OFDM and CATV signals in different frequency bands, the overall network structure is simplified and the available bandwidth for the OFDM signals is increased. Furthermore, by carefully adjusting the driving voltage of the employed CATV transmitter, the overall transmission performance can be optimized by eliminating a large amount of unwanted distortions. Unlike the current fiber optical CATV transport system in which the CATV signals need to be amplified in every 30 ~40 km transmission span, the proposed architecture has successfully extended the transmission span to 60 km. This can practically remove the needs of electrical power provisioning and monitoring between the central office (CO) and each local exchange (LE). Good transmission performances of carrier-to-noise ratio (CNR), composite second-order (CSO), composite triple beat (CTB) and bit error rate (BER) were obtained for the transmitted CATV and OFDM signals. All of these experimental results prove the practice and efficiency of the proposed architecture in providing simplicity and extended reach services to customers.

Fiber optical CATV transport systems based on PM and light injection-locked DFB LD as a duplex transceiver.

A bidirectional fiber optical CATV transport system employing phase modulation (PM) scheme and frequency up-conversion technique to deal with downstream CATV signals, and using light injection-locked distributed feedback laser diode (DFB LD) as a duplex transceiver at the receiving site is proposed and experimentally demonstrated. With optimum injection wavelength and power level, a DFB LD is efficiently employed for both the transmitter and receiver operations. Such DFB LD is used to replace the functions of delay interferometer (DI) and CATV receiver, and also to be as the upstream light source. To the best of our knowledge, it is the first time to successfully utilize a DFB LD to detect the phase-modulated CATV signals. Impressive experimental results prove that our proposed systems not only can employ the PM scheme and the frequency up-conversion technique to optimize the overall performances of systems, but also can use an injection-locked DFB LD to detect the downstream phase-modulated CATV signals as well as to transmit the upstream CATV ones simultaneously.

Bidirectional direct modulation CATV and phase remodulation radio-over-fiber transport systems.

A bidirectional lightwave transport system employing direct modulation CATV and phase remodulation radio-over-fiber (ROF) signals in two-way transmission is proposed and experimentally demonstrated. To be the first system of reusing the phase of the transmitting lightwave with multi-carrier analog CATV signal, the transmission performances of CATV and ROF signals are investigated in bidirectional way, with the help of optical band-pass filters (OBPFs) at the receiving sites. Through a serious investigation, the transmitting light sources are successfully remodulated with RF signals for transmission. Brilliant transmission performances of composite second-order (CSO), composite triple-beat (CTB), and bit error rate (BER) were obtained; accompanied with acceptable carrier-to-noise ratio (CNR) value. This proposed system reveals a prominent one with economy and convenience to be installed.