Sven Loquai

Recent Results From the EU POF-PLUS Project: Multi-Gigabit Transmission Over 1 mm Core Diameter Plastic Optical Fibers

Recent activity to achieve multi-gigabit transmission over 1 mm core diameter graded-index and step-index plastic optical fibers for distances up to 50 meters is reported in this paper. By employing a simple intensity-modulated direct-detection system with pulse amplitude or digital multi-tone modulation techniques, low-cost transceivers and easy to install large-core POFs, it is demonstrated that multi-gigabit transmission up to 10 Gbit/s over 1-mm core diameter POF infrastructure is feasible. The results presented in this paper were obtained in the EU FP7 POF-PLUS project, which focused on applications in different scenarios, such as in next-generation in-building residential networks and in datacom applications.

Beyond 1 Gbit/s Transmission Over 1 mm Diameter Plastic Optical Fiber Employing DMT for In-Home Communication Systems

Multi-Gbit/s transmission over 1 mm diameter graded index plastic optical fiber (GI-POF) is reported. Transmission rates between 5.3 and 7.6 Gbit/s are achieved for fiber lengths between 10 and 50 m using discrete multi-tone modulation (DMT) in an intensity modulated direct detection system using directly modulated eye-safe VCSEL and silicon photodiode (PD). The used system bandwidth is only 1.42 GHz resulting in a spectral efficiency of bits/s/Hz. All employed components represent a low-cost, off-the-shelf cost-effective solution for high-speed in-home communication systems.

Comparison of Modulation Schemes for 10.7 Gb/s Transmission Over Large-Core 1 mm PMMA Polymer Optical Fiber

The authors give an overview of experimental results on 10.7 Gb/s over large-core 1 mm polymethyl-methacrylate (PMMA) polymer optical fiber (POF). The comparison starts with simple non-return-to-zero (NRZ) transmission without equalization. Next, measurement results with feed-forward-, decision -feedback equalization (FFE, DFE) and maximum likelihood sequence estimation (MLSE) are presented. Finally, experimental results with more advanced modulation schemes like pulse amplitude modulation (PAM) and discrete multitone (DMT) modulation are investigated. The experiments were carried out with a Vertical-Cavity Surface-Emitting Laser (VCSEL) at 0 dBm to comply with consumer eye-safety regulation or with a 10 mW laser diode (LD) that could be used in active optical cables.

Comparison of PAM and CAP Modulation Schemes for Data Transmission Over SI-POF

An experimental comparison of multilevel modulation schemes for polymer optical fiber (POF) transmission systems is shown in this letter. The performance of a non-return-to-zero, pulse-amplitude modulation (PAM), and carrierless amplitude phase (CAP) modulation was tested under the different conditions, including various link lengths and fiber-coupled power. As an optical transmitter, the commercial laser diode operating at 655 nm was used. A maximum bit rate of 5 Gb/s over 50-m 1-mm step-index POF link was achieved with 16-CAP modulation format at +6 dBm fiber-coupled power and a bit-error ratio of 10-3. Over 100 m, a maximum bit rate of 3.4 Gb/s was realized with 4-PAM.

10 Gbit/s over 25 m plastic optical fiber as a way for extremely low-cost optical interconnection

In this paper we demonstrate for the first time that large diameter (½ to 1 mm) step index POF can be used for 10 Gbit/s transmission over up to 25 m with very low-cost components and DMT modulation. The use of bend insensitive multi-core POF reduces the bending radius to 2.5 mm without any signal distortion resulting in a very robust installation.

Eye-Safe Data Transmission of 1.25 Gbit/s Over 100-m SI-POF Using Green Laser Diode

We report on 1.25-Gbit/s transmission over 100-m step-index polymer optical fiber (SI-POF) with 6.5-dB margin. Nonreturn-to-zero modulation with offline decision feedback equalization technique has been applied to an intensity modulated direct-detection optical channel. An edge emitting direct injection laser diode with 515 nm is used, which allows us to improve the system power budget due to a lower attenuation of the POF at this wavelength. The fiber-coupled optical power has been adjusted to 0 dBm which corresponds to eye-safety requirements.

10.7-Gb/s Discrete Multitone Transmission Over 50-m SI-POF Based on WDM Technology

The capacity of the transmission link based on standard 1-mm core-diameter step-index plastic optical fiber (SI-POF) is strictly limited due to the strong attenuation and inter-modal dispersion. Parallel transmission of the data streams using several optical carriers might overcome the mentioned limits and allows for low-bandwidth transmitters and receivers. In this letter, we demonstrate the implementation of wavelength-division multiplexing technology with three laser diodes operating at 405, 515, and 650 nm with +7.1, +5.4, and +4 dBm fiber-coupled power. The 10.7-Gb/s data transmission based on the offline-processed discrete multitone modulation technique has been realized over 50-m SI-POF at the bit-error ratio of 10-3.

GaN Light-Emitting Diodes for up to 5.5-Gb/s Short-Reach Data Transmission Over SI-POF

We report a high-speed data transmission over a 1-mm diameter step-index polymer optical fiber (SI-POF) with GaN light-emitting diodes (LEDs) operating at 435 and 475 nm. The modulation bandwidths of the LEDs at 40 mA were 180 and 300 MHz, respectively. A maximum bit rate of 5.5 Gb/s was achieved with a 475-nm GaN LED at -1.8-dBm fiber-coupled power over a 1-m SI-POF employing 4-pulse-amplitude modulation format. Compared with the performance of a high-speed red resonant-cavity LED under the same test setup, the chromatic dispersion reduces the potential of the GaN LED-based system when the transmission distance is longer than 30 m.

High-Speed, Large-Area POF Receivers for Fiber Characterization and Data Transmission

The authors report on high-speed, very large-area, visible light photoreceivers suitable for large-core 1 mm polymer optical fibers (POF). The receivers are based on metal-semiconductor-metal photodetectors (MSM-PD) grown on gallium-arsenide (GaAs) substrate. Three active diameters of Ø1000 μm, Ø700 μm and Ø400 μm were fabricated in order to meet the requirements of the following three specific POF applications. The first photoreceiver was designed to characterize the bandwidth of 1 mm POF. For that reason the receiver has an active diameter of Ø1000 μm to detect all modes at the end of the fiber. With this receiver the frequency response of 1 mm graded-index (GI-) POF was measured up to 12 GHz. The Ø700 μm photoreceiver was designed for high-speed data transmission. Due to the large active area there is no need for an optical concentrator and the 1 mm POF can simply be butt-coupled to the receiver. With this receiver a novel real-time transmission of 10 Gb/s over up to 20 m GI-POF using simple non return to zero (NRZ) modulation is presented. For data rates beyond 10 Gb/s the Ø400 μm photoreceiver with a 3-dB bandwidth of 11 GHz was designed. A record bit rate of 32 Gb/s was transmitted with this receiver over large-core 1 mm polymethylmethacrylate (PMMA) GI-POF. These achieved results are by far the best reported values for large-area visible light photoreceivers.

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We report on 10.7-Gb/s transmission over 25-m multicore polymer optical fiber (MC-POF) which allows a robust transmission and ease of installation including tight bends. The discrete multitone modulation technique is applied to the intensity-modulated direct-detection optical channel in order to achieve high spectral efficiency. The use of bend-insensitive MC-POF reduces significantly the admissible bending radius to 2.5 mm without any signal distortion resulting in a very robust installation. The POF-optimized receiver comprises a silicon pin photodiode with an active diameter of 400 and a transimpedance amplifier.