Plastic Optical Fiber Links Research Articles

Stabilized Plastic Optical Fiber Link Even Without a Physical-Contact Fiber Connection

Stabilized Plastic Optical Fiber Link Even Without a Physical-Contact Fiber Connection

Optical Communication and Positioning Convergence for Flexible Underwater Wireless Sensor Network

This paper presents a novel scheme based on underwater optical wireless communication and positioning (UOWC-UOWP) for an underwater wireless sensor network (UWSN). A dual-hop system is adopted to extend the limited coverage area of the UWSN with mobile nodes, consisting of a grade-index plastic optical fiber (GI-POF) link and a wireless link. Specifically, the mini-LED offers high-speed and flexible uplink transmission and the high-power LED enables both downlink transmission and positioning. The time frame design and code division multiplexing access (CDMA) support multi-user signal transmission. Proof-of-concept experiments with GI-POF and wireless link demonstrate the feasibility of the proposed scheme, which offers full-duplex communication, high-precise positioning and extended distance. To the best of our knowledge, the UOWC-UOWP convergent system is proposed for the first time. It has great potential to support high-capacity transmission between mobile nodes for future underwater transmission scenarios.

Integrated transceiving chip based on RCLED and PIN-PD for plastic optical fiber link

In this paper, we propose a monolithically integrated optical transceiving chip (IOTC) scheme by vertically integrating a resonant cavity enhance LED (RCLED) on its top side and a PIN-PD at its bottom side. It can be used for promoting the application of single fiber bi-direction (BiDi) transmission in plastic optical fiber (POF) link. For a fabricated IOTC, the transmitting function is realized by its RCLED unit, which emits light upwards to a POF at 804.6 nm with a FWHM of 4 nm. The receiving function is realized by its PIN-PD unit, which collects the light, while it passing through its RCLED unit, from the same POF. For realizing the transmitting and receiving function simultaneously, firstly, high optical isolation performance between the ITOC’s two units should be realized, which means the RCLED’s backlight should be as little as possible compared with its top emitting light. And the obtained optical isolation level between the fabricated IOTC’s two units is higher than 30 dB. Secondly, high photo-response isolation performance between the ITOC’s two units also need to be realized, which means the RCLED’s photo-response to the receiving light should be as little as possible compared with the PIN-PD’s photo-response. For the fabricated IOTC, it realizes a responsivity of 0.42A/W at the receiving wavelength around 831 nm and a photo-response isolation level of higher than 70 dB between its two units. For dynamic performance, the IOTC’s RCLED unit obtains a 3 dB modulation bandwidth of 2.2 GHz, and its PIN-PD unit obtains a 3 dB photo-response bandwidth of 10.6 GHz. Within the 10.6 GHz bandwidth, the dynamic isolation level between the two units is higher than 30 dB. It should be feasible to be used for constructing in-home single POF BiDi optical link.

Design of an All-POF-Fiber Smartphone Multichannel Breathing Sensor With Camera-Division Multiplexing

We report the design and prototyping of an all-fiber-smartphone multiplexed sensor, with the purpose of breathing rate analysis. The architecture is based on a multichannel extrinsic sensor based on intensity modulation. The sensing system is entirely based on plastic optical fiber (POF). The optical hardware is entirely based on the smartphone, using the flashlight LED as the source and the camera as the pixel-based detector. A 3-D printed connector has been fabricated to facilitate light coupling to and from the POF links. A multiplexing concept labeled “camera-division multiplexing” has been implemented and is reported for a three-fiber system: The camera is spatially tessellated, dividing the contribution of each fiber with crosstalk 8.2–15.3 dB. The application for breathing rate detection, with camera ISO set to 800, is proposed and implemented, visualizing the power spectral density of the respiration pattern.

Intrinsically Stabilized Plastic Optical Fiber Link Subject to External Optical Feedback

We develop a graded-index plastic optical fiber (GI POF) that can significantly stabilize a multimode fiber (MMF) link with a vertical-cavity surface-emitting laser (VCSEL) subject to external optical feedback. It is demonstrated that the dominant mechanism for this stabilization effect is the strong mode coupling of the GI POF, which is closely related to the polymer-specific microscopic heterogeneities in the GI POF core material. Such mode coupling decreases correlation between the problematic reflected light field and VCSEL cavity field, increasing tolerance of the MMF link for external optical feedback. Our developed GI POF with specific microscopic heterogeneities prevents the external-optical-feedback-induced critical destabilization observed for silica GI MMFs. These results suggest that the stabilization effect can be controlled by microscopic properties regardless of the fiber attenuations and core refractive indices.

Characterization of a Y-Coupler and Its Impact on the Performance of Plastic Optical Fiber Links

Couplers and splitters are common devices in single-mode and multi-mode glass fibers applications, where they perform a variety of functions. However, when switching to plastic optical fibers (POFs), there is a shortage of commercial devices, which are usually custom-made. The problem with these devices is that modal power distribution in POFs is easily modified by spatial disturbances that produce a localized strong power transfer between modes, thus changing their transmission properties. In this work, a commercial Y-coupler designed for POFs is experimentally characterized. Measurements of its spectral, spatial and temporal characteristics have been performed, including insertion loss as a function of wavelength, angular power distribution, and frequency response. The obtained results show that this device has an equalizing effect over the power spatial distribution that reduces the fiber bandwidth, demonstrating the importance of considering the impact of this type of devices on the transmission properties of any POF system.

Design of a Smartphone Plastic Optical Fiber Chemical Sensor for Hydrogen Sulfide Detection

We present a low-cost, handheld plastic optical fiber (POF) sensor for hydrogen sulfide (H2S) detection integrated onto a smartphone. The sensor uses smartphone flashlight as a source and camera as a pixel-based intensity detector. The POF is interconnected to the smartphone with a 3-D-printed connector on both source/detector sides. The sensing mechanism is embedded in the fiber link, making the system an all-fiber smartphone architecture. A mobile application handles data acquisition on the Android operative system. The sensor is functionalized for H2S detection through silver deposition on the POF outer surface. Experiments demonstrate the feasibility of the sensor system as the presence of H2S is successfully measured through an increase of optical losses through the POF link. This cost-effective, scalable, and compact sensor is promising for application in environmental sensing.

A simple and inexpensive optical power monitor for two visible wavelength WDM channels in plastic optical fibre links

This paper shows for the first time, to the best of our knowledge, the design of a simple, non-invasive, bidirectional and inexpensive optical power monitor (OPMo) for WDM over PMMA-based polymer optical fibre (POF) links transmitting 470 nm and 650 nm wavelengths light carriers. Low-cost cellophane plastic optical filters were used for each WDM channel aiming to demonstrate the OPMo operational principle. The OPMo is non-invasive because it does not tap any guided light from the fibre core; rather, it collects and detects the spontaneous side-scattered light. A sensitivity of −32 dBm and dynamic range of 38.8 dB were measured. A crosstalk rejection better than 25 dB was achieved when both light carriers are of the same power.

Evaluation of modal noise in graded-index silica and plastic optical fiber links for radio over multimode fiber systems

We have evaluated and compared modal noise induced in a graded-index silica multimode fiber (GI-MMF) link and a graded-index plastic optical fiber (GI-POF) link with the misaligned fiber connections. In radio over fiber (RoF) systems using these optical fibers, modal noise appears as unwanted amplitude modulation in the received signal, and results in degradation of the RoF transmission performance. In this work, we have evaluated the modal noise induced in GI-MMFs and GI-POFs with its same core diameter of 50 μm. Our results show that GI-POFs have an inherently higher tolerance to misaligned connection and less modal noise than GI-MMFs in terms of both the error-vector magnitude and the speckle pattern of the transmitted signals.

Optoelectronic high-speed HDMI cable with compact optical sub-assembly and 4×3.4 Gbit/s plastic optical fibre link

Presented is a composite optoelectronic high-speed high-definition multimedia interface (HDMI) cable with the application of an optical link running on four thin GI 50/125 μm plastic optical fibres to serve upcoming demand in consumer electronics. The thin fibres enable a compact optical sub-assembly that in return fits inside the cable connector. The main advantages of this technology are pointed out and the packaging of the composite HDMI connectors outlined. Cable performance and in particular the waveform diagrams as well as bit error ratio results at 3.4 Gbit/s that enable full HD video transmission over 10 m are included.

Multistandard Wireless Transmission Over SSMF and Large-Core POF for Access and In-Home Networks

An end-to-end transmission of coexisting multistandard radio (LTE, WiMAX, and UWB) signals is demonstrated for the first time with the transmission over a combined access and in-home networks consisting of 25-km SSMF, 25-m large-core diameter polymethylmethacrylate graded-index plastic optical fiber link and 1-m wireless. The residential gateway includes O-E-O conversion to connect the access and in-home parts of the networks. This letter demonstrates a fully integrated radio signal distribution scenario from the central station to the end-user personal area networks.

A 150-Mb/s CMOS Monolithic Optical Receiver for Plastic Optical Fiber Link

This paper describes a 150-Mb/s monolithic optical receiver for plastic optical fiber link using a standard CMOS technology. The receiver integrates a photodiode using an N-well/P-substrate junction, a pre amplifier, a post amplifier, and an output driver. The size, PN-junction type, and the number of metal fingers of the photodiode are optimized to meet the link requirements. The N-well/P-substrate photodiode has a 200-μm by 200-μm optical window, 0.1-A/W responsivity, 7.6-pF junction capacitance and 113-MHz bandwidth. The monolithic receiver can successfully convert 150-Mb/s optical signal into digital data through up to 30-m plastic optical fiber link with -10.4 dBm of optical sensitivity. The receiver occupies 0.56-mm2 area including electrostatic discharge protection diodes and bonding pads. To reduce unnecessary power consumption when the light is not over threshold or not modulating, a simple light detector and a signal detector are introduced. In active mode, the receiver core consumes 5.8-mA DC currents at 150-Mb/s data rate from a single 3.3 V supply, while consumes only 120 μW in the sleep mode.

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.

LDPC-Coded OFDM for Heterogeneous Access Optical Networks

In this paper, we propose a heterogeneous optical access networking scenario, in which communication links between source and destination nodes are heterogeneous, composed of free-space optical, plastic optical fiber (POF), and indoor infrared (IR) links. To deal with bandwidth limitations of POF and IR links, a power-variable rate-adaptive low-density parity-check (LDPC)-coded orthogonal frequency division multiplexing (OFDM) scheme is used, while to deal with atmospheric turbulence, the spatial diversity is used. The rate-adaptive LDPC codes are designed using a modified progressive edge-growth (MPEG) algorithm. We show that with the proposed heterogeneous communication systems, we can deliver a high-speed optical signal (40 Gb/s and beyond) to an end-user.

Material dispersion interplay with spectral filtering on plastic optical fiber (POF) links

AbstractThis article reports on the material dispersion interplay with spectral filtering that shifts the bandwidth of Poly‐Methyl‐Metacrylate plastic optical fiber links. Calculations were carried out on fiber lengths up to 500 m and 100 m in length for <600 and 650 nm visible wavelength channels, respectively. The rise time budget evaluation is improved. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1657–1662, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24425

Improvements of resolution and precision of a wavelength-encoded electrical current sensor using an ultra-bright light-emitting diode transducer

A wavelength-encoded electrical current sensor for high voltage using ultra-bright green (525 nm) light-emitting diode (LED) transducer and plastic optical fibre (POF), linking to remote location, has been developed. The wavelength receiver is based on passive filtering by employing an OG530 edge filter. LEDs from three different manufactures were characterized in their optical chirp response range, aiming for a sensor resolution improvement. The sensor precision (stability) was improved against external perturbations on the POF link by using an in-line mode-scrambler. The environment temperature of the LED transducer was kept unchanged at ±2°C.

Modal bandwidth enhancement in a plastic optical fiber by W-refractive index profile

A plastic optical fiber (POF) having a W-shaped refractive index profile (W-shaped POF) was prepared for the first time that had a possibility to realize a higher bit rate transmission than those of the conventional silica-based multimode fiber and graded index (GI) POF links. Since the W-shaped POF has a valley of the refractive index at the boundary of the core and cladding of the conventional graded-index (GI) POF, the group delay of higher order modes is strongly influenced, and the modal dispersion in the GI POF is compensated. By comparing the propagating mode properties of the W-shaped POF with those of the GI POF, we clarified theoretically and experimentally that the index valley has a remarkable modal dispersion compensation effect.

Broad spectra receivers for wavelength-encoded electrical current measurement based on light-emitting diode transducer

We report on novel optical receivers for demodulation of wavelength-encoded signals, from ultra-bright green light-emitting diodes (LEDs), used as high-voltage electrical current optical transducers, operating at stable environmental temperature. The intensity/wavelength-modulated light is transmitted to the receiver on the ground potential, by means of a plastic optical fibre (POF) link. Wavelength demodulation of the broad spectra is achieved by means of passive or active filtering based receiver, to overcome the known drawbacks of intensity-modulated sensors. Passive filtering receiver uses OG 530 coloured (orange) glass edge filter, with 12 nm spectral range. It has shown 23 times more slope sensitivity than the (brown) polymer edge filter, but the latter has shown a larger spectral range of 40 nm. An immunity of at least 23 dB under light attenuation was achieved. Measurements with and without modal scrambling are qualitatively described, aiming at sensor stability. Active receivers are built from a commercial double PN junction colour sensor, but could work for dc current sensing only.

High-Bandwidth Plastic Optical Fiber With W-Refractive Index Profile

A plastic optical fiber having a W-shaped refractive index profile [W-shaped plastic optical fiber (POF)] was prepared for the first time to realize a higher bit rate transmission than those of the conventional silica-based multimode fiber and graded-index (GI) POF links. Since the W-shaped POF has a valley of the refractive index at the boundary of the core and cladding of the conventional GI POF, the group delay of higher order modes is strongly influenced, thus compensating the modal dispersion that exists in the GI POF. The modal dispersion compensation effect by the W-shaped index profile was theoretically and experimentally confirmed.

Optical Interconnects on and in Printed Circuit Boards

Two types of short distance optical interconnects for on-board applications are presented: Small diameter plastic optical fibre (POF) links and multimode polymer waveguide layers integrated in multilayer printed circuit boards (PCB). POF links with fibre numbers up to 128 and link lengths up to 50 cm are realized with total transmission loss values below 2 dB at 660 nm. First tests of 10 cm long temperature stable multimode polymer waveguides laminated into standard multilayer PCBs demonstrate the capabilities of combined electrical-optical circuit boards.