Chien-An Chu

10 m/25 Gbps LiFi transmission system based on a two-stage injection-locked 680 nm VCSEL transmitter.

A 10  m/25  Gbps light-based WiFi (LiFi) transmission system based on a two-stage injection-locked 680 nm vertical-cavity surface-emitting laser (VCSEL) transmitter is proposed. A LiFi transmission system with a data rate of 25 Gbps is experimentally demonstrated over a 10 m free-space link. To the best of our knowledge, it is the first time a two-stage injection-locked 680 nm VCSEL transmitter in a 10  m/25  Gbps LiFi transmission system has been employed. Impressive bit error rate performance and a clear eye diagram are achieved in the proposed systems. Such a 10  m/25  Gbps LiFi transmission system provides the advantage of a communication link for higher data rates that could accelerate the deployment of visible laser light communication.

Bidirectional fiber-wireless and fiber-VLLC transmission system based on an OEO-based BLS and a RSOA.

A bidirectional fiber-wireless and fiber-visible-laser-light-communication (VLLC) transmission system based on an optoelectronic oscillator (OEO)-based broadband light source (BLS) and a reflective semiconductor optical amplifier (RSOA) is proposed and experimentally demonstrated. Through an in-depth observation of such bidirectional fiber-wireless and fiber-VLLC transmission systems, good bit error rate performances are obtained over a 40 km single-mode fiber and a 10 m RF/optical wireless transport. Such a bidirectional fiber-wireless and fiber-VLLC transmission system is an attractive option for providing broadband integrated services.

Hybrid CATV/MMW/BB lightwave transmission system based on fiber-wired/fiber-wireless/fiber-VLLC integrations.

A hybrid lightwave transmission system for cable television (CATV)/millimeter-wave (MMW)/baseband (BB) signal transmission based on fiber-wired/fiber-wireless/fiber-visible laser light communication (VLLC) integrations is proposed and demonstrated. For down-link transmission, the light is intensity-modulated with 50-550 MHz CATV signal and optically promoted from 25 GHz radio frequency (RF) signal to 10 Gbps/50 GHz and 20 Gbps/100 GHz MMW data signals based on fiber-wired and fiber-wireless integrations. Good performances of carrier-to-noise ratio (CNR), composite second-order (CSO), composite triple-beat (CTB), and bit error rate (BER) are obtained over a 40-km single-mode fiber (SMF) and a 10-m RF wireless transport. For up-link transmission, the light is successfully intensity-remodulated with 5-Gbps BB data stream based on fiber-VLLC integration. Good BER performance is achieved over a 40-km SMF and a 10-m free-space VLLC transport. Such a hybrid CATV/MMW/BB lightwave transmission system is an attractive alternative, it gives the benefits of a communication link for broader bandwidth and higher transmission rate.

A Bidirectional Hybrid Lightwave Transport System Based on Fiber-IVLLC and Fiber-VLLC Convergences

This paper proposes and validates a bidirectional hybrid lightwave transport system based on fiber-invisible laser light communication (IVLLC) and fiber-visible laser light communication (VLLC) convergences with light injection and optoelectronic feedback techniques. This paper is also the first to employ light injection and optoelectronic feedback techniques in a bidirectional lightwave transport system based on fiber-IVLLC and fiber-VLLC integration. Light is successfully modulated directly with cable television (CATV), 16-quadrature amplitude modulation (QAM), and 16-QAM-orthogonal frequency-division multiplexing (OFDM) signals. Good carrier-to-noise ratio, composite second order, composite triple beat, and bit error rate (BER) are obtained for CATV, 16-QAM, and 16-QAM-OFDM signal transmissions over a combined 40-km single-mode fiber, a 1.43-km photonic crystal fiber, and 6-m free-space transmission. The proposed bidirectional hybrid lightwave transport system exhibits significant potential in providing broadband integrated services, such as CATV, Internet, and telecommunication, via optical fiber and free-space indoor networks.

A 20-m/40-Gb/s 1550-nm DFB LD-Based FSO Link

An innovative free-space optical (FSO) link using laser light propagation to achieve transmission rate of 40 Gb/s at a wavelength of 1550 nm is proposed and experimentally demonstrated. Over a 20-m free-space link, brilliant bit-error-rate performance and clear eye diagram are obtained in the proposed 1550-nm distributed feedback (DFB) laser diode (LD)-based FSO links. As far as we know, it is the first time that a 1550-nm externally modulated laser transmitter cascaded with an erbium-doped fiber amplifier and a pair of fiber collimators to successfully set up a 20-m/40-Gb/s FSO link has been employed. Compared with the 680-nm vertical-cavity surface-emitting laser-based FSO link, this proposed 1550-nm DFB LD-based FSO link is attractive not only because it has longer free-space transmission distance but because it supplies higher bandwidth operation as well. Such a 1550-nm DFB LD-based FSO link provides the benefits of optical wireless communications for longer transmission distance and higher transmission rate, which is thoroughly helpful for optical wireless network applications.

A 50-m/40 Gb/s 680-nm VCSEL-Based FSO Communication

A 50-m/40-Gb/s 680-nm vertical-cavity surface-emitting laser (VCSEL)-based free-space optical (FSO) communication employing three-stage injection-locked technique and the afocal scheme is proposed and experimentally demonstrated. The three-stage injection-locked technique, which can significantly increase the resonant frequency of the VCSEL, is expected to provide higher transmission rate in FSO communication. The afocal scheme, which can reduce the beam size of laser beam, is expected to provide longer free-space link in FSO communication. As far as we know, it is the first time that a three-stage injection-locked 680-nm VCSEL transmitter and afocal scheme that will successfully build up a 50-m/40-Gb/s FSO communication has been employed. Such a 50-m/40-Gb/s FSO communication provides the advantages of optical wireless links for longer transmission distance and higher transmission rate, which is thoroughly useful for high-speed light-based WiFi (LiFi) applications.

150 m/280 Gbps WDM/SDM FSO link based on OEO-based BLS and afocal telescopes.

A 150 m/280 Gbps free-space optical (FSO) link based on an optoelectronic oscillator (OEO)-based broadband light source (BLS), afocal telescopes, and wavelength-division-multiplexing (WDM)/space-division-multiplexing (SDM) convergence is proposed. Experimental results show that the transmission distance of FSO links is significantly increased by afocal telescopes, and the transmission rate of FSO links is greatly enhanced by WDM and SDM convergence. With the aid of a low noise amplifier and clock/data recovery, good bit error rate performance and a clear eye diagram are achieved at 150 m/280 Gbps operation. This proposed 150 m/280 Gbps WDM/SDM FSO link is shown to be a prominent alternative not only because of its advancement of indoor FSO communications but also because of the advantages of optical wireless communications for a long transmission distance and high transmission rate.

A 100 m/320 Gbps SDM FSO link with a doublet lens scheme

A 100 m/320 Gbps space-division-multiplexing (SDM) free-space optical (FSO) link with a doublet lens scheme is proposed and experimentally demonstrated. The transmission capacity of FSO links is increased significantly by the SDM topology, and the transmission distance of FSO links is greatly extended by the doublet lens scheme. An FSO link of eight channels over a 100 m free-space link with a total transmission rate of 320 Gbps (40 Gbps/λ × 8λ = 320 Gbps) is achieved. With the assistance of a low noise amplifier (LNA) and clock/data recovery (CDR) at the receiving site, a good bit error rate (BER) performance and a clear eye diagram are obtained at 100 m/320 Gbps. The proposed 100 m/320 Gbps SDM FSO link is shown to be a notable option to provide the advantages of long transmission distances and high transmission rates for optical wireless communications.

Fiber-Wireless and Fiber-IVLLC Convergences Based on MZM-OEO-Based BLS

Fiber-wireless and fiber-invisible laser light communication (IVLLC) convergences that adopt the Mach-Zehnder modulator-optoelectronic oscillator (MZM-OEO)-based broadband light source for microwave (MW)/millimeter-wave (MMW)/baseband (BB) signal transmission are proposed and demonstrated. For downlink transmission, light is optically promoted from 15- and 25-GHz radio-frequency (RF) signals to 10-Gb/s/30-GHz MW, 15-Gb/s/50-GHz MMW, 20-Gb/s/60-GHz MMW, and 25-Gb/s/100-GHz MMW data signals based on fiber-wireless and fiber-IVLLC integrations. Bit error rate (BER) performs efficiently in the 40-km single-mode fiber (SMF) and the 10-m RF/25-m optical wireless transport scenarios. For uplink transmission, downstream light is successfully intensity-modulated with a 25-Gb/s BB data stream based on fiber-IVLLC integration. BER performs efficiently in the 40-km SMF and the 100-m optical wireless transport scenario. Such a hybrid MW/MMW/BB lightwave transmission system is an attractive alternative. It is shown to be a prominent one to present advancements in integrating fiber backbone and radio-frequency (RF)/optical wireless feeder networks.

A Bidirectional Wireless-Over-Fiber Transport System

This study proposes and demonstrates a bidirectional wireless-over-fiber (WoF) transport system based on an optical interleaver, a phase modulator, and an optical bandpass filter (OBPF)-based phase-modulation-to-intensity-modulation converter that can deliver intensity-modulated 60 GHz millimeter-wave (MMW), 30 GHz microwave (MW), and phase-remodulated 15 GHz MW data signals. A broadband light source, comprising an optoelectronic oscillator scheme and an optical signal-to-noise ratio (OSNR) enhancement scheme, is deployed in these bidirectional 60 GHz/30 GHz/15 GHz WoF transport systems. For downlink transmission, light is promoted optically from a 5 Gbps/ 15 GHz MW data signal to 5 Gbps/60 GHz MMW and 5 Gbps/30 GHz MW data signals in fiber-wireless convergence. The downstream light is phase remodulated successfully using a 5 Gbps/15 GHz MW data signal for uplink transmission. Through a thorough examination of such bidirectional 60 GHz/30 GHz/15 GHz WoF transport systems, the bit error rate (BER) is observed to perform well over a 40 km single-mode fiber and a 4 m RF wireless transmission. This bidirectional 60 GHz/30 GHz/15 GHz WoF transport system is a prominent alternative not only because of its advancement in integrating optical fiber and RF wireless networks but because of the benefits of communication links for broader bandwidth and higher transmission rate as well.