External Light Injection Technique Research Articles

20-Gbps optical LiFi transport system.

A 20-Gbps optical light-based WiFi (LiFi) transport system employing vertical-cavity surface-emitting laser (VCSEL) and external light injection technique with 16-quadrature amplitude modulation (QAM)-orthogonal frequency-division multiplexing (OFDM) modulating signal is proposed. Good bit error rate (BER) performance and clear constellation map are achieved in our proposed optical LiFi transport systems. An optical LiFi transport system, delivering 16-QAM-OFDM signal over a 6-m free-space link, with a data rate of 20Gbps, is successfully demonstrated. Such a 20-Gbps optical LiFi transport system provides the advantage of a free-space communication link for high data rates, which can accelerate the visible laser light communication (VLLC) deployment.

Dispersion penalty analysis using light injection method in the feedforward optical transmitter for WDM/SCM radio-over-fiber systems

We have experimentally and theoretically demonstrated the transmission performance of a feedforward optical transmitter using an external light injection technique. The feedforward compensation method shows 31 dB intermodulation distortion suppression and 2.2 dB noise reduction. The feedforward architecture used a wavelength-locked Fabry–Perot laser diode whose side-mode suppression ratio about 35 dB over a 12-nm range. The suppression characteristics of the intermodulation distortion for various wavelength differences and transmission lengths were measured and analyzed as the evaluation criteria for the system performance in WDM/SCM based radio-over-fiber systems.

A bidirectional radio-on DWDM transport system for LAN and ITS applications

A bidirectional radio-on dense-wavelength-division-multiplexing (DWDM) transport system based on external light injection technique and adaptive filters is proposed. Not only were a low bit-error rate and error vector magnitude obtained, but also good performance of third-order intermodulation distortion to carrier ratio (IMD/sub 3//C) was achieved for local area network (LAN) and intelligence transport system (ITS) applications.

A CATV Lightwave Transport System Based on Fabry-Perot Laser and External ASE Light Injection Technique

We propose a low cost WDM optical source using split band technology and external ASE light injection for CATV signals transmission. Good performance of carrier-to-noise ratio (CNR), composite second order (CSO) and composite triple beat (CTB) were observed over 30 km SMF transmission.

CATV/radio-on-fiber transport system based on direct modulation

A directly modulated CATV/radio-on-fiber (ROF) transport system based on external light injection technique, optical single sideband (SSB) filter, and RF amplifier predistorter is proposed and demonstrated. To the best of my knowledge, it is the first time to transmit CATV and ROF signals simultaneously in a directly modulated form. Good performances of carrier-to-noise ratio (CNR), composite second order (CSO) and composite triple beat (CTB) were obtained for CATV band; and low third order intermodulation distortion to carrier ratio (IMD3/C), and bit error rate (BER) values were achieved for ROF application.

A radio-on-hybrid WDM transport system

A radio-on-hybrid wavelength-division-multiplexing (WDM) transport system based on distributed feedback laser diodes and semiconductor optical amplifiers with double external light injection techniques is proposed and demonstrated. Good performances of bit-error rate, modulation-error ratio, carrier-to-noise ratio, error vector magnitude, and third-order intermodulation distortion-to-carrier ratio were achieved in our proposed systems. This demonstrated that such a radio-on-hybrid WDM transport system is attractive for 256-quadrature amplitude modulation/gigabit Ethernet, 2.4-GHz/local area network, and 5.8-GHz/intelligence transport system signals.

Employing double external light injection techniques to improve radio-on-DWDM system performance

A radio-on-dense-wavelength-division-multiplexing (DWDM) transport system employing double external light injection techniques to improve the systems' overall performance is proposed and demonstrated. Simultaneously using the external light injection technique to enhance the bandwidth of the vertical-cavity surface-emitting laser and increase the saturation output power of the semiconductor optical amplifier, resulting in a system with better transmission performance.

Transmission improvement of vertical cavity surface emitting lasers at 4×2.5 Gbit/s under a semiconductor optical amplifier with external light injection technique

A 10-Gbit/s wavelength-division-multiplexing (WDM) transport system over a 50-km single-mode fiber (SMF) transport based on vertical cavity surface emitting lasers (VCSELs) and a semiconductor optical amplifier (SOA) with an external light injection technique is proposed and demonstrated. Improved bit error rate (BER) performance is observed under direct modulation of four channels at 2.5 Gbit/s, attributed to the SOA light injection technique to reduce the SOA-induced distortion and crosstalk.

Improved Performance of Fabry-Perot Laser Diode Transport System with External Light Injection Technique

We use external light injection technique to improve the performance of Fabry-Perot laser diodes. The external light injection technique progresses the performance of carrier-to-noise ratio (CNR), composite second order (CSO), and composite triple beat (CTB) of fiber optical cable television (CATV) system.

Radio-on-Multimode Fiber Systems Based on VCSELs and External Light Injection Technique

A radio-on-multimode fiber (MMF) system based on 1.55-μm vertical-cavity surface-emitting lasers (VCSELs) and an external light injection technique is proposed and demonstrated. Low error vector magnitude, third-order intermodulation distortion to carrier ratio, and bit-error-rate values were obtained in our proposed radio-on-MMF systems. Using VCSELs as optical sources in radio-on-MMF systems are very attractive, as they are relatively simple to fabricate and potentially low cost. Such a proposed radio-on-MMF system is suitable for the short-haul microwave optical link.

A-10Gbit/s lightwave transport system based on VCSEL and SOA with external light injection technique

A-10Gbit/s lightwave transport system over a-50km large effective area fiber (LEAF) tranmission based on vertical cavity surface emitting laser (VCSEL) and semiconductor optical amplifier (SOA) with external light injection technique is proposed and demonstrated. Improved bit error rate (BER) performance was observed under direct modulation of 10Gbit/s, attributed to the LEAF to reduce the total fiber dispersion and SOA light injection technique to suppress the SOA-induced distortion. This demonstrated lightwave transport system is very attractive for the 10Gbit/s backbone applications, which can inter-operate with high-speed optical communication networks.

Employing double external light injection techniques to improve radio-on-fiber systems performance

A radio-on-fiber (ROF) transport system employing double external light injection techniques to improve systems’ performance is proposed and demonstrated for the first time. Simultaneously using external light injection techniques to increase the frequency response of the laser diode and the saturation output power of the semiconductor optical amplifier (SOA), leading to decrease third order intermodulation distortion (IMD 3) and SOA gain-saturation-induced distortion. Such a proposed ROF transport system is suitable for the long-haul microwave optical links.

Fiber optical CATV system-performance improvement by using external light-injection technique

A directly modulated amplitude modulation with vestigial sideband cable television (CATV) erbium-doped fiber amplifier-repeated system that uses an external light-injection technique is proposed and demonstrated. The external light-injection technique greatly enhances the frequency response of the laser diode, and thus improves the overall performance of the fiber optical CATV system.

Improved performance of an externally modulated system with external light injection technique

An externally modulated amplitude modulated-vestigial sideband (AM-VSB) CATV erbium-doped fiber amplifier (EDFA)-repeated system that uses external light injection technique is proposed and demonstrated. Good performances of carrier-to-noise ratio, composite second order, and composite triple beat were achieved with 0-dBm light injection over a 100-km single-mode fiber transport.