Showing papers in "Fibers in 1992"
TL;DR: In this paper, the authors used a polarization controller to adjust the polarization into a fiber to one of the principal states of polarization of the fiber, which eliminates first-order polarization dispersion.
Abstract: In this paper, we describe a demonstration of the optical equalization of polarization dispersion in direct-detection lightwave systems. We use a polarization controller to adjust the polarization into a fiber to one of the principal states of polarization of the fiber, which eliminates first-order polarization dispersion. Results for a 2.5 Gbps, externally modulated system with a fiber with 120 ps rms of polarization dispersion, show that by using the equalizer we maintain a 10-9 BER, while without the technique the BER varies with time from 10-5 to 10-9. At 10 Gbps, the equalizer allows reliable bit detection even though the eye is closed without equalization, demonstrating an order of magnitude increase in the dispersion-limited B2L product, in agreement with our analytical and computer simulation results. We also describe a demonstration of the technique at the receiver, and show how to implement an adaptive polarization controller to continuously track the principal states using a gradient search algorithm. This technique provides bit-rate-independent equalization of first-order polarization dispersion.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
23 citations
TL;DR: It is shown that under appropriate conditions, coherent CDMA can in principle rival wavelength-division multiplexing (WDM) in terms of aggregate network throughput.
Abstract: Recent work in optical code division multiple access (CDMA) is reviewed, progressing from incoherent to coherent techniques. It is shown that under appropriate conditions, coherent CDMA can in principle rival wavelength-division multiplexing (WDM) in terms of aggregate network throughput. Furthermore, it is shown that at high data rates, some of the components for WDM and coherent CDMA networks are nearly identical, indicating a similarity between the two approaches. CDMA retains a coding aspect which may prove attractive in security applications.
10 citations
IBM1
TL;DR: In this paper, the design of a packet-switched wavelength-division-multiplexed (WDM) metropolitan area fiber-optic network with multiple rf subcarrier channels multiplexed on each wavelength is described.
Abstract: In this paper we describe the design of a packet-switched wavelength-division-multiplexed (WDM) metropolitan area fiber-optic network with multiple rf subcarrier channels multiplexed on each wavelength We also describe the experimental verification of the key features of this network Each station (node) in the network is assigned a unique wavelength and rf subcarrier for reception and a unique wavelength for transmission Packet-switching can be accomplished by a combination of rapid tuning between rf subcarriers on the same wavelength at the transmitter and multihop; wavelength tunability is not required When fully implemented, our network is capable of supporting 32 wavelengths spaced 1 nm apart and five amplitude-shift- keyed (ASK) subcarrier channels, each operating at 200 Mb/s and spaced 400 MHz apart, on each wavelength, and can achieve an aggregate throughput of 7 Gb/s© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering Downloading of the abstract is permitted for personal use only
10 citations
TL;DR: This paper addresses some new features and characteristics of queuing in optical packet switches and focuses on the fundamental performance limitations associated with `all-optical' packet switches, in which the packet buffering is implemented via fiber delay lines.
Abstract: Recently, there has been an increased awareness of the impact queuing plays in the performance and design of high-performance packet switches. For instance, the importance of memory sharing and trunking is generally accepted by researchers and developers today, especially when one considers `real' traffic that is `bursty.' Burstiness can result from the sources themselves, and can be exacerbated by store-and-forward networks. In this paper, we address some new features and characteristics of queuing in optical packet switches. All of the fundamental results (e.g., the performance advantages of output queuing and the memory reduction of buffer sharing) still apply to optical packet switches. However, the limited state of optical technology (e.g., the lack of an optical random access memory) puts constraints on the architecture of optical packet switches. The lack of an optical random access memory led many in the past to propose hybrid switch architectures that exploit the advantages of both optics and electronics, using electronics for the queuing of packets. Here, we instead focus our attention on the fundamental performance limitations associated with `all-optical' packet switches, in which the packet buffering is implemented via fiber delay lines.
7 citations
TL;DR: This paper describes three basic codes and their corresponding routing processor architectures, and several new logic primitives are introduced including optical set logic and lambda-gates.
Abstract: The high bandwidth of optical fibers and photonic switching devices offers the potential to increase the usable bandwidth in packet switched networks and interconnects. In this paper we describe several methods to code packetized information using both the time and optical frequency domains. The presence or absence of optical power at discrete optical wavelengths is treated as units of information, resulting in two-dimensional coded packets which may be processed using novel, perhaps more efficient routing architectures. We describe three basic codes and their corresponding routing processor architectures. Several new logic primitives are introduced including optical set logic and lambda-gates. The resulting information capacities for these codes and the associated routing processor complexity, and efficiency in terms of number of mappings per gate are discussed.
5 citations
TL;DR: In this paper, the PTM family and its potential for use in high-speed fiber systems intended for transmission of analogue data are discussed. But the authors focus on the use of PTM in a high-performance bandwidth-efficient fiber communication system at an acceptable cost.
Abstract: A principal factor in realizing a high-performance bandwidth-efficient fiber communication system at an acceptable cost is the choice of modulation format on the optical carrier. In this context pulse time modulation (PTM) techniques represent an attractive alternative to purely digital or analogue methods. This paper reviews the PTM family and explores their potential for use in high-speed fiber systems intended for transmission of analogue data.
5 citations
TL;DR: A 100 Mbit/s optical CDMA experiment in free space demonstrating the feasibility of the all-serial coding architecture using a serial combination of 50/50 beam splitters and retroreflectors at 10 Tchip/s with 100 fs laser pulses is reported.
Abstract: In optical code-division multiple access (CDMA), the architecture of optical encoders/decoders is another important factor that needs to be considered, besides the correlation properties of those already extensively studied optical codes. The architecture of optical encoders/decoders affects, for example, the amount of power loss and length of optical delays that are associated with code sequence generation and correlation, which, in turn, affect the power budget, size, and cost of an optical CDMA system. Various CDMA coding architectures are studied in the paper. In contrast to the encoders/decoders used in prime networks (i.e., prime encodes/decoders), which generate, select, and correlate code sequences by a parallel combination of fiber-optic delay-lines, and in 2n networks (i.e., 2n encoders/decoders), which generate and correlate code sequences by a serial combination of 2 X 2 passive couplers and fiber delays with sequence selection performed in a parallel fashion, the modified 2n encoders/decoders generate, select, and correlate code sequences by a serial combination of directional couplers and delays. The power and delay- length requirements of the modified 2n encoders/decoders are compared to that of the prime and 2n encoders/decoders. A 100 Mbit/s optical CDMA experiment in free space demonstrating the feasibility of the all-serial coding architecture using a serial combination of 50/50 beam splitters and retroreflectors at 10 Tchip/s (i.e., 100,000 chip/bit) with 100 fs laser pulses is reported.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
5 citations
TL;DR: In this article, an original model is established and used to predict the spectral properties of optical fiber pulse position modulation (PPM) and a suitable random variable is built into the model to represent the stochastic data sequence encoded, which is then used to examine the problem of slot synchronization under two conditions, first when the channel dispersion is negligible, then when Gaussian type pulses are received.
Abstract: An original model is established and used to predict the spectral properties of optical fiber pulse position modulation (PPM). A suitable random variable is built into the model to represent the stochastic data sequence encoded. The spectral prediction is then used to examine the problem of slot synchronization under two conditions, first when the channel dispersion is negligible, then when Gaussian type pulses are received. The model is shown to be capable of catering for the different PPM parameters and is used to optimize slot synchronization using these parameters under each of the two conditions. Practical results measured on a PPM system are given and shown to agree with the theoretical predictions, concluding with those conditions that optimize slot synchronization.
4 citations
TL;DR: In this article, a new laser diode simulator for general multisection and multielectrode structures is introduced, which allows to evaluate thermal effects in order to obtain more realistic results also at high injection rates.
Abstract: In this paper we introduce a new laser diode simulator for general multisection and multielectrode structures. Lasing mode features like linewidth, intensity and frequency modulation responses, etc., are calculated considering all the major physical effects. Furthermore, this model allows us to evaluate thermal effects in order to obtain more realistic results also at high injection rates.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
3 citations
TL;DR: Signaling via space-time coding is proposed for asynchronous multiple access free-space and fiber-based optical communications and interference mitigation and preliminary simulation results are carried out to demonstrate operating principles.
Abstract: Signaling via space-time coding is proposed for asynchronous multiple access free-space and fiber-based optical communications and interference mitigation. Preliminary simulation results are carried out to demonstrate operating principles.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
3 citations
TL;DR: The performance and operation of an optically processed coherent optical CDMA network based on electronically reconfigurable optical phase-addressing is described and shown to be an attractive system when flexible and extensive multiple access is required.
Abstract: The performance and operation of an optically processed coherent optical CDMA network based on electronically reconfigurable optical phase-addressing is described. It is compared to both coherent and incoherent all-optical approaches based on time-addressing and shown to be an attractive system when flexible and extensive multiple access is required.
TL;DR: In this article, the steady state and dynamic properties of a DFB amplifier have been analyzed from theoretical and experimental viewpoints, and the linewidth enhancement factor has been estimated from the experimental hysteresis cycle using an inversion technique of the device transmissivity.
Abstract: The steady-state and dynamic properties of a DFB amplifier have been analyzed from theoretical and experimental viewpoints. The linewidth enhancement factor has been estimated from the experimental hysteresis cycle using an inversion technique of the device transmissivity. The dynamic behavior of the DFB has been tested at 622 Mbit/s and the experimental results are supported by numerical simulations based on an assessed model.
TL;DR: In this article, a non-uniform, open-type stripline compensator was proposed to compensate the fiber group delay by adjusting the width distribution of the striplines.
Abstract: A group delay in an optical fiber is one of the major factors limiting the transmission distance of a long-distance, high bit-rate optical fiber communication system using in-line erbium doped fiber amplifiers (EDFAs). The group delay can be compensated by a delay equalizer (a stripline section, for instance) inserted in the intermediate frequency stage of a coherent receiver. The purpose of this paper is to propose a method for compensating the fiber group- delay precisely by adjusting the width distribution of a nonuniform, open-type stripline compensator and thus optimizing its group-delay characteristics. It is shown that, by using the optimized nonuniform stripline, the overall group-delay dispersion is reduced to approximately 1/20 of the value obtained with an ordinary, uniform stripline compensator. The effectiveness of the optimized stripline was confirmed by a computer simulation of the entire system.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: An `almost-all' optical packet switch architecture that does not rely on recirculating loops for storage implementation and estimated that transparent-bit-rate 32 X 32 switches may easily be implemented with ECL logic.
Abstract: In this paper, we present an `almost-all' optical packet switch architecture that does not rely on recirculating loops for storage implementation. Our architecture is based on two rearrangeably non-blocking stages interconnected by optical delay lines with different amount of delay. We've investigated the probability of loss as a function of link utilization and the size of the switch. In general, with proper setting of the number of delay lines, the switch can achieve arbitrarily low probability of loss. The latency characteristics of the switch were also investigated. Possible design of the electronic control circuit was shown. We estimated that transparent-bit-rate 32 X 32 switches may easily be implemented with ECL logic.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: Besides the conceptual relevance of new multilevel modulation formats proposed to exploit the transmission characteristics of single-mode optical fibers, important applications can be foreseen like, for example, multiple parallel paths between network nodes or transmission between different processing units of supercomputers.
Abstract: A review is presented of multilevel coherent and DD optical transmission systems with the aim of a comparative analysis between conventional modulation formats, such as N-PSK, N-QAM and new modulation/demodulation techniques, such as N-4QSK, N-SPSK and PM-DD. Besides the conceptual relevance of new multilevel modulation formats proposed to exploit the transmission characteristics of single-mode optical fibers, important applications can be foreseen like, for example, multiple parallel paths between network nodes or transmission between different processing units of supercomputers.
TL;DR: In this article, the authors describe some novel architectures for optical TDM switching, and an experimental system working at 720 Mb/s; this includes a complete BER characterization, which is composed of 2 X 2 optical switches and delay lines.
Abstract: This paper describes some novel architectures for optical TDM switching, and an experimental system working at 720 Mb/s; this includes a complete BER characterization. The architectures are composed of 2 X 2 optical switches and delay lines. The trade-offs between the various factors affecting their design are explored, and a wide range of architectures are presented suitable for different applications.
TL;DR: In this article, a family of systems developed to make better use of the vast usable bandwidth provided by optic fibers is described, and a suitable filter-amplifier configuration is proposed for each possible application, like LANs, WANs and Long Haul Systems.
Abstract: This paper describes a family of systems developed to make better use of the vast usable bandwidth provided by optic fibers. All systems described are frequency division multiplexed (FDM). Special attention is paid to the possibility of reducing channel spacing by signal processing using optic filters and of improving receiver sensitivity by using Erbium-doped fiber amplifiers (EDFA). A suitable filter-amplifier configuration is proposed for each possible application, like LANs, WANs, and Long Haul Systems.
TL;DR: In this paper, the authors considered the possibility of optimizing 1.55 micrometers MS-TWAs with respect to the length and the electrical injection level of each homogeneously pumped region and to the input signal wavelength.
Abstract: Semiconductor laser amplifiers have been the object of increasing interest in recent years. Such an interest is due to the possibility of low noise direct amplification of optical signals in future high speed and coherent optical transmission systems. The travelling wave amplifier (TWA) is a Fabry-Perot amplifier (FPA) with anti-reflection coated end facets. TWAs present the disadvantage of a higher spontaneous emission noise level, which in FPAs is reduced by the wavelength selective cavity effect. On the other hand, the spectral characteristics of FPAs also mean a reduced signal bandwidth and the possibility of undesirable amplified signal reflections. With respect to homogeneously pumped laser amplifiers, multi-section structures for TWAs (MS-TWAs) seem to be attractive from the point of view of both the adjustable parameters (electrical pumping of each section) and the device performances in terms of gain saturation characteristics and four-wave mixing. In this paper we consider the possibility of optimizing 1.55 micrometers MS-TWAs with respect to the length and the electrical injection level of each homogeneously pumped region and to the input signal wavelength. The optimization is accomplished by taking into account the continuous-wave (cw) gain-output power characteristics and the thermal effects within the device. The analysis of the transient behavior shows that optical input pulses can undergo considerable amplitude distortion, if the amplifier is not properly designed.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this article, a solution which only requires nearest-neighbor interconnections in the frequency domain is proposed and discussed for OFDM systems based on multistage interconnection networks with space-frequency interstage patterns.
Abstract: For OFDM systems based on multistage interconnection networks with space-frequency interstage patterns the number of crossed channels and the interconnection length in the frequency domain is aimed to be a minimum. A solution which only requires nearest-neighbor interconnections in the frequency domain is proposed and discussed.
TL;DR: This paper proposes that advantage be taken of the fiber non-linearity such that the n-ary PPM pulse becomes a temporal soliton, and examines the maximum achievable bit rate of such a system and compares it to that of PCM.
Abstract: In n-ary PPM, a single high energy pulse is used to convey M bits of information. In this paper we propose that advantage be taken of the fiber non-linearity such that the n-ary PPM pulse becomes a temporal soliton. We examine the maximum achievable bit rate of such a system and compare it to that of PCM. We show that under ideal conditions (no fluctuations of the input soliton pulse width) n-ary PPM can be used to achieve a higher bit-rate than PCM. However, in a practical situation fluctuations of the input soliton pulse width are translated to variations in the soliton pulse position. We show that this has a severe effect on the error probability of n-ary PPM and that in this situation PCM offers greater immunity. Finally, we consider the implications of the Gordon-Haus effect on the maximum transmission distance of n-ary PPM and show that it is less than that for PCM due to the narrower pulse arrival time window.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: The exact expression of the bit error rate (BER) for optical soliton communication systems with lumped amplifiers is proposed in consideration of the combined effect of timing jitter and energy fluctuation.
Abstract: The exact expression of the bit error rate (BER) for optical soliton communication systems with lumped amplifiers is proposed in consideration of the combined effect of timing jitter and energy fluctuation. Some numerical examples are given. The dependence of the BER and the optimal fiber dispersion on the amplification period and transmission distance are discussed.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this article, a detailed theoretical analysis is given for the impact of finite frequency deviation on the sensitivity of dual-filter heterodyne frequency shift keying (FSK) lightwave systems.
Abstract: A detailed theoretical analysis is given for the impact of finite frequency deviation on the sensitivity of dual-filter heterodyne frequency shift keying (FSK) lightwave systems. Our analysis provides closed-form signal-to-noise ratio (SNR) results for estimating the bit-error- ratio (BER) performance of the system. These closed-form results provide an insight into the impact of finite frequency deviation 2(Delta) fd, laser linewidth (Delta) (nu) , bit rate Rb, and IF filter bandwidths on the system performance. Simulation results indicate that the accuracy of the approximate theory presented in this paper is within 1 dB for linewidths up to 22% when BER equals 10-9. It is shown that there is a well-defined relationship between the choice of frequency deviation and the tolerable amount of laser phase noise. When there is no phase noise, a frequency deviation of 2(Delta) fd equals 0.72 Rb is sufficient for 1 dB sensitivity penalty with respect to infinite frequency deviation case; whereas for a linewidth of (Delta) (nu) equals 0.50 Rb the required frequency deviation increases to 2(Delta) fd equals 3.42 Rb for the same sensitivity penalty. The sensitivity degradation can be very severe for a fixed linewidth as the frequency deviation gets smaller: for a linewidth of 20% the sensitivity penalty is only 0.54 dB when the frequency deviation is infinite whereas it is 3.48 dB when the frequency deviation is 2(Delta) fd equals Rb.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this article, the effects of amplitude shift keyed (ASK) modulation on a phase shift-keyed (PSK) receiver were evaluated in a coherent optical wavelength division multiplexed (WDM) local area network.
Abstract: STARNET is a coherent optical wavelength division multiplexed (WDM) local area network. In STARNET, the use of low level amplitude modulation of phase modulated light has been proposed to implement a packet-switched ring network in addition to a high speed circuit- switched network. To verify the feasibility and characterize the effects of amplitude shift- keyed (ASK) modulation on a phase shift-keyed (PSK) receiver, we have measured the sensitivity of a 1.244 Gb/s PSK synchronous heterodyne receiver in the presence of 125 Mb/s ASK modulation. The experiments show that the unmodified (i.e., designed for no ASK modulation) PSK receiver successfully operates with a bit error ratio less than 10-9 and maintains phase-lock in the presence of ASK modulation for ASK modulation indexes less than 0.5.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this article, the authors proposed enhancements to the STARNET, a previously proposed wavelength division multiplexed broadband optical local area network, which offers the users both a medium speed packet-switched ring network and a high speed circuit interconnection.
Abstract: We propose enhancements to STARNET, a previously proposed wavelength division multiplexed broadband optical local area network STARNET offers the users both a medium- speed packet-switched ring network, and a high-speed circuit interconnection The enhanced architecture, STARNET-E, improves performance in both the packet and the circuit interconnect sections over the previous version Performance analysis of the STARNET-E packet network shows that this data transport facility can be upgraded to Gb/s total throughput with little added complexity with respect to the original STARNET Moreover, we show that STARNET nodes can be enhanced to allow reconfigurable multihop topologies with little added optical hardware The throughput of multihop distributed switching over a passive star physical topology in STARNET-E is compared to the throughput of an active centralized switch STARNET-E offers to all nodes a Gb/s total throughput packet transport facility and a high speed circuit interconnect, simultaneously and independently In addition, a node can trade the high speed circuit interconnect service for a multihop broadband packet network without the need for any added optical hardware
TL;DR: In this paper, the performance of FSK-IM systems operating at 10 Gb/s is analyzed, and the sensitivity and the linewidth requirements are estimated, showing that for 1 dB sensitivity penalty, the linwidth requirements for heterodyne systems are higher.
Abstract: Direct frequency modulation of a DFB laser followed by FM to IM conversion in an interferometer is a promising technique to produce low chirp transmitters to be used in high speed direct detection systems. In this paper, the performance of FSK-IM systems operating at 10 Gb/s is analyzed, and the sensitivity and the linewidth requirements are estimated. A comparison between FSK-IM systems and FSK heterodyne systems is also performed, showing that for 1 dB sensitivity penalty, the linewidth requirements for heterodyne systems are higher.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this paper, the application of subcarrier multiplexing (SCM) in an OFDM system employing FM direct detection techniques is discussed, and component characteristics which affect system performance are discussed and results presented.
Abstract: Applying a subcarrier multiplexing technique (SCM) in an optical frequency division multiplexing system (OFDM) will improve utilization of the optical channel, at the same time increasing the flexibility in designing an optical network. In this paper, system examples based on the combination of these two techniques ar discussed. Particular attention is given to the application of SCM in OFDM systems which employs FM direct detection techniques. Component characteristics which affect system performance are discussed and results presented.
TL;DR: In this paper, phase diversity homodyne receivers are analyzed when there is a difference in path lengths between the two quadrature components, and bit error rate (BER) floors due to laser phase noise are calculated.
Abstract: Phase diversity homodyne receivers are analyzed when there is a difference in pathlengths between the two quadrature components. Bit error rate (BER) floors due to laser phase noise are calculated. The result shows more sensitivity than one would estimate from heuristic calculations.
TL;DR: In this paper, the performance of Manchester-coded optical wavelength division multiplexing (WDM) systems is evaluated taking into account the shot noise and the four wave mixing (FWM) caused by fiber nonlinearities.
Abstract: The performance of Manchester-coded optical wavelength division multiplexing (WDM) systems is evaluated taking into account the shot noise and the four wave mixing (FWM) caused by fiber nonlinearities. The result is compared to conventional non-return-to-zero (NRZ) systems for ASK and DPSK modulation formats. Further, the dynamic range, defined as the ratio of the maximum transmitter power (limited by the FWM) to the minimum transmitter power (limited by receiver sensitivity) is evaluated. For 1.55 micrometers 16 channel WDM systems, the dynamic range of Manchester coded systems show as 2 dB improvement with respect to the NRZ; DPSK systems outperform ASK systems by 5.5 dB. This result holds true for both dispersion-shifted fiber and conventional fiber; it has been obtained for 10 GHz channel spacing, 1 Gbps/channel bit rate and 100 Km transmission length.
TL;DR: A comprehensive multiple processor simulator that has been developed to execute parallel algorithms using the MCA as a data transport mechanism between processors and memory units is described.
Abstract: A parallel processing architecture based on multiple channel optical communication is described and compared with existing interconnection strategies for parallel computers. The proposed multiple channel architecture (MCA) uses MQW-DBR lasers to provide a large number of independent, selectable channels (or virtual buses) for data transport. Arbitrary interconnection patterns as well as machine partitions can be emulated via appropriate channel assignments. Hierarchies of parallel architectures and simultaneous execution of parallel tasks are also possible. Described are a basic overview of the proposed architecture, various channel allocation strategies that can be utilized by the MCA, and a summary of advantages of the MCA compared with traditional interconnection techniques. Also describes is a comprehensive multiple processor simulator that has been developed to execute parallel algorithms using the MCA as a data transport mechanism between processors and memory units. Simulation results -- including average channel load, effective channel utilization, and average network latency for different algorithms and different transmission speeds -- are also presented.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this article, a preliminary report on an ongoing experimental effort aimed at the implementation of a prototype of a lightwave digital coherent transmission system based on polarization modulation, or polarization shift keying (POLSK), is presented.
Abstract: This paper is a preliminary report on an ongoing experimental effort aimed at the implementation of a prototype of a lightwave digital coherent transmission system based on polarization modulation, or polarization shift keying (POLSK). Several devices specifically designed and built for the experiment are presented. The state of the experimental project is assessed.