Step-index Plastic Optical Fiber Research Articles

DFT-Spread DMT Modulation for 1Gbps Transmission Rate over 100m of 1mm SI-POF

In this letter, the discrete Fourier transform-spread discrete multitone modulation (DFT-spread DMT) scheme has been used for the first time in laser-based short range optical transmission (over 100 m) with 1-mm step-index plastic optical fiber link, and its superior performance, compared with the standard DMT scheme, was demonstrated. The DFT-spread DMT combines the advantages of both single carrier and multicarrier transmission together with a lower peak-to-average power ratio. Under the same experimental conditions, a lower bit-error-rate is achieved with DFT-spread DMT compared with standard DMT for transmission rates in the 1-Gb/s range.

1 Gbit/s transmission over step-index plastic optical fiber using an optical receiver with an integrated equalizer

A single chip optical receiver with an integrated large-diameter photodiode, transimpedance amplifier, two stages active equalizer, post amplifier and 50 Ω driver is used for gigabit transmission over PMMA step plastic optical fiber (SI-POF). The large-diameter photodiode with an antireflection coating optimized for red light. The integrated equalizer enables the presented optical receiver to reach 1 Gbit/s over 50 m SI-POF at bit error ratio of 10 − 6 . An error free (< 10 − 9 ) 1 Gbit/s data rate over 40 m standard PMMA step-index plastic optical fiber is also achieved.

Influence of the angle-dependence of mode coupling on optical power distribution in step-index plastic optical fibers

Determination of the power distribution in step index plastic optical fibers by the power flow equation has been reported in the literature both with and without the simplifying assumption of constant coupling that is independent of the angle of light propagation. The need for this assumption is evaluated in this paper. Results with the angle-dependent coupling coefficient are compared to those derived under the simplifying assumption of constant coupling. Benchmarked to values measured experimentally, this comparison covered the coupling lengths L c (denoting where the equilibrium mode distribution is achieved in the fiber) and lengths z s (for achieving the steady-state distribution). Results differ slightly but only for longer fiber lengths, thus largely vindicating the simplifying assumption of constant coupling.

Space-time block code based MIMO encoding for large core step index plastic optical fiber transmission systems

The performance of Space-Time Block Codes combined with Discrete MultiTone modulation applied in a Large Core Step-Index POF link is examined theoretically. A comparative study is performed considering several schemes that employ multiple transmitters/receivers and a fiber span of 100 m. The performance enhancement of the higher diversity order configurations is revealed by application of a Margin Adaptive Bit Loading technique that employs Chow's algorithm. Simulations results of the above schemes, in terms of Bit Error Rate as a function of the received Signal to Noise Ratio, are provided. An improvement of more than 6 dB for the required electrical SNR is observed for a 3 × 1 configuration, in order to achieve a 10(-3) BER value, as compared to a conventional Single Input Single output scheme.

On Bit and Power Loading for OFDM Over SI-POF

A new methodology is proposed for the modeling of practical uncoded bit and power loading schemes for OFDM, based on the assumption of a uniform transmit power spectrum. The accuracy of this technique, both in terms of predicted maximum data rate and occupied bandwidth, is demonstrated analytically for an Intensity Modulated/Direct Detected (IM/DD) system over Step Index Plastic Optical Fibers (SI-POF). It is shown that both this new methodology and the well known water pouring theorem accurately predict the maximum achievable data rate in practical uncoded systems; however, it is also demonstrated that the new methodology is a better predictor of the bandwidth occupied by the transmit signal, thus providing an important analytical tool for system designers. The analysis presented is also experimentally verified using an IM/DD optical system employing a directly modulated Resonant Cavity Light Emitting Diode (RCLED) light source and several lengths of 1 mm SI-POF.

Assessment of the impact of localized disturbances on SI-POF transmission using a matrixpropagation model

Our aim is to extend the matrix approach of the power flow equation to study the effects ofdifferent devices over light propagation in step index plastic optical fibers (SI-POFs). Herewe devise an experimental method to characterize a particular scrambler as amatrix which can be directly introduced into the model framework to predicttransmission properties. Thus, fiber bandwidth versus length was simulated fordifferent scrambler configurations and then compared with experimental data toverify the characterization method. A study of the scrambler effects for differentlaunching conditions reveals important aspects of its impact on transmission.

Calculation of the frequency response in step-index plastic optical fibers using the time-dependent power flow equation

The time-dependent power flow equation, which is reduced to its time-independent counterpart is employed to calculate frequency response and bandwidth in addition to mode coupling and mode-dependent attenuation in a step-index plastic optical fiber. The frequency response is specified as a function of distance from the input fiber end. This is compared to reported measurements. Mode-dependent attenuation and mode dispersion and coupling are known to be strong in plastic optical fibers, leading to major implications for their frequency response in data transmission systems.

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.

A Pluggable Large Core Step Index Plastic Optical Fiber With Built-In Mode Conditioners for Gigabit Ultra Short Reach Networks

Large core step-index plastic optical fibers (SI-POF) are bandwidth limited due to their high modal dispersion and coupling loss at the receiver. To date, the large core SI-POF are typically deployed up to 150 Mb/s applications. This paper reports the transmission of 2.5 Gb/s on 980 μm core step-index plastic optical fiber with fiber-based mode conditioning elements that are part of the connector assembly. The built-in mode conditioners are tapered fiber tips that provide restricted mode launching at transmitter and mode filtering at the receiver side. The structures, at the tip of POF, are optimized by optical simulations and fabricated using laser fusion process. The connector assembly is realized by precisely encapsulating the mode conditioners with a metallic ferrule and positioned using optical grade epoxies. These plug-in modules are inserted to a typical SFP transceiver LC connector receptacle and characterized for gigabit rates.

Determination of the width of the output angular power distribution in step-indexmultimode optical fibers

Two functions for calculating the width of the output angular power distribution are testedfor light launched centrally along the axis of a step-index plastic optical fiber. It is foundthat the more recent of the two agrees better with experimental measurements. The otherfunction (Gloge’s) underestimates the output width for longer fiber lengths, which isattributed to it not accounting for an appropriate boundary condition at the criticalpropagation angle.

Investigation of influence of tilt angle on mode dispersion in step-index plastic optical fibers

AbstractEffect of numerical aperture on mode dispersion and bandwidth is reported for commercially available step-index plastic optical fibers. For the first time, the functional relationship is given between dispersion and the “tilt-angle” describing the slant of the input/output face for a fiber terminated by a plane not perpendicular to the fiber axis. This tilt of a non-squarely terminated fiber may be intentional as in some biomedical spectroscopic sensors, or otherwise when exploiting the quick-interconnectivity potential of plastic fibers.

170 Mb/s multilevel transmission over 115 m standard step-index plastic optical fiber using an integrated optical receiver

An optical receiver having a high linearity is used for multilevel communication over standard step plastic optical fiber. A large-diameter photodiode with an antireflection coating optimized for red light was integrated. These features enable the used optical receiver to be a promising plastic optical fiber receiver. An error free (< 10 −8) 170 Mb/s data rate over 115 m standard PMMA step-index plastic optical fiber is achieved with four-level and eight-level pulse amplitude modulation.

An integrated optical receiver for multilevel data communication over large core step index plastic optical fiber

A BiCMOS integrated optical receiver with high sensitivity and good linearity is presented. An automatic gain control transimpedance amplifier (TIA) and linear post amplifiers are used to maintain a high linearity with multilevel modulation. Using multilevel signaling and large-diameter integrated photodiodes make the presented optical receiver suitable for small-bandwidth high-attenuation large-core PMMA step index plastic optical fiber. A measured sensitivity of ?31 dBm (BER = 10?9) at 250 Mb/s is presented for a binary signal. A data rate of 500 Mb/s and a sensitivity of ?25 dBm (BER = 10?9) are achieved with four-level pulse amplitude modulation (4-PAM). An error-free transmission over 40 m PMMA step index plastic optical fiber was achieved at 500 Mb/s using 4-PAM signaling with the presented multilevel optical receiver.

Experimental Proof-of-Concept of Bidirectional Gigabit Transmission Over Single Step-Index Plastic Optical Fiber

We demonstrated a Gigabit bidirectional transmission over a single step-index plastic optical fiber running at 20 m. The solution is attractive for potentially low-cost consumer electronic short-distance cabling at a high data rate requiring simple installation. In particular, thanks to the extremely small cable diameter (2.2 mm overall), it may find applications in brown-field installations that have to reuse existing ducts.

An optical receiver for eight-level data communication over step index plastic optical fiber

An optical receiver with automatic-gain-control transimpedance amplifier, linear post amplifier and linear line driver suitable for multilevel signals is presented. A large-diameter photodiode (400 μm) with an antireflection coating optimized for red light was integrated. These features enable the presented optical receiver to be a promising plastic optical fiber receiver. An error free (<10 −8) 400 Mbit/s data rate over 50 m PMMA-step index plastic optical fiber (1 mm diameter) is achieved with eight-level pulse amplitude modulation (8-PAM).

Real-time gigabit DMT transmission over plastic optical fibre

For the first time, a real-time 1.25 Gbit/s discrete multitone (DMT) transmitter implemented in a field-programmable gate array is demonstrated for use in low-cost, standard 1 mm step-index plastic optical fibre applications based on a commercial resonant-cavity LED and a large-diameter Si-photodiode.

Comparison of Methods for Calculating Coupling Length in Step-Index Optical Fibers

A recently reported function for calculation of the coupling length at which the equilibrium mode distribution is achieved in step-index plastic optical fibers is compared to a long established calculation method and to experimental findings. The recent function, while simpler to apply as it eliminates the need to numerically solve the power flow equation repeatedly for every case, is also more accurate for high numerical aperture (0.45 to 0.5) plastic optical fibers.

Calculation of the Impulse Response of Step-Index Plastic Optical Fibers Using the Time-Dependent Power Flow Equation

The analytical solution of the time-dependent power flow equation is employed to calculate impulse response in a step-index plastic optical fiber. Results are given at different fiber lengths and are shown to agree with those reported in the literature. Mode-dependent attenuation, modal dispersion and mode coupling in plastic optical fibers are known to affect fiber-optic power delivery, data transmission, and sensing systems.

Discrete Multitone Modulation for Maximizing Transmission Rate in Step-Index Plastic Optical Fibers

The use of standard 1-mm core-diameter step-index plastic optical fiber (SI-POF) has so far been mainly limited to distances of up to 100 m and bit-rates in the order of 100 Mbit/s. By use of digital signal processing, transmission performance of such optical links can be improved. Among the different technical solutions proposed, a promising one is based on the use of discrete multitone (DMT) modulation, directly applied to intensity-modulated, direct detection (IM/DD) SI-POF links. This paper presents an overview of DMT over SI-POF and demonstrates how DMT can be used to improve transmission rate in such IM/DD systems. The achievable capacity of an SI-POF channel is first analyzed theoretically and then validated by experimental results. Additionally, first experimental demonstrations of a real-time DMT over SI-POF system are presented and discussed.

Frequency response in step index plastic optical fibers obtained from the generalized power flow equation

We present a method to obtain the frequency response of step index (SI) plastic optical fibers (POFs) based on the power flow equation generalized to incorporate the temporal dimension where the fibre diffusion and attenuation are functions of the propagation angle. To solve this equation we propose a fast implementation of the finite-difference method in matrix form. Our method is validated by comparing model predictions to experimental data. In addition, the model provides the space-time evolution of the angular power distribution when it is transmitted throughout the fibre which gives a detailed picture of the POFs capabilities for information transmission. Model predictions show that angular diffusion has a strong impact on temporal pulse widening with propagation.