III-V optical sources for high bit rate fiber transmission

With the global deployment of wavelength division multiplexing (WDM), many fibre manufacturers are developing new exotic fibre types. These have been designed to support long haul high bit rate transmission as afforded through optical multiplexing. However, high channel rate NRZ WDM transmission is impaired considerably by both the linear and non-linear fibre effects. These effects are further compounded as the channel rates migrate from 10 Gbps to 40 Gbps. The correct choice of fibre type required to support multichannel high bit rate transmission on such systems becomes of critical importance. We report on the performance of the ubiquitous non-dispersion shifted fibre (NDSF) type, SMF28/sup TM/, and in particular its performance with various dispersion compensation schemes. Furthermore we investigate the implications and performance of NZ-DS fibre types. The NZ-DS fibre types considered comprise the large effective area NZ-DSF and the standard NZ-DSF.

We have demonstrated that mid-span spectral inversion by four-wave mixing in a semiconductor optical amplifier can be used to effectively eliminate dispersion in high bit rate transmission. The technique has been used to achieve transmission of 1OGb/s signals from a directly modulated DFB over 200km dispersive fibre, and of 25ps gain-switched pulses over 100km dispersive fibre. The results show a complete elimination of degradation resulting from fibre chromatic dispersion. The former result represents more than a 40-fold increase in the bit rate distance product for the directly modulated signals by means of MSSI.

We investigate detectors for transmultiplexer-based high bit rate transmission over dispersive channels like telephone wires. The transmitter is based on a synthesis stage. At the receiver side, we design, for an MMSE criterion, multiple-input/multiple-output (MIMO) linear detectors applied after an analysis stage and upgraded with a MIMO decision-feedback (DF) section. The performance of the system is investigated for filter banks over copper wires with different noises (AWGN, FEXT and RFI). The influence of the forward section rate is investigated. The potential of these detectors is clearly demonstrated. Besides, reduced complexity solutions are also put forward.

Distributed feedback (DFB) lasers are used extensively as optical sources within fiber optic telecommunications systems. These semiconductor lasers are valued for their single optical mode operation which enables their use in high bit rate digital and broadband analog transmission systems. We discuss requirements imposed upon DFB lasers used in such applications. We briefly review and illustrate general techniques for modeling DFB laser operation by comparison of measured and modeled device characteristics below and above lasing threshold. We focus on the phenomenon of spatial hole burning which substantially affects operation of all DFB lasers, especially those tailored to produce high fiber coupled power from a single mirror facet. We illustrate insights gained by measurement and modeling of DFB lasers using as an example the particular case of analog transmission of multichannel video signals.

Offset Quadri Phase Shift Keying (OQPSK) modulation schemes, due to their constant envelope characteristics, are becoming attractive for high bit rate digital transmission systems particularly space communication systems which adopt non linear power amplifiers. An OQPSK modulator for modulating high bit rate data on an X-band carrier has been developed. Description of the modulator along with simulated results and test results are presented in this paper. Issues concerned with the spectrums of QPSK and OQPSK are discussed.

In the current era of the new media, because of the influence of new media, the traditional radio and television is transforming to the IP network structure. This paper has referred the standard SMPTE ST2022-6-2012 to detail of the high bit rate media signals transmission in the IP network data mapping, protocol encapsulation and requirements. It has given a brief introduction to the trend of television center's infrastructure trans to IP network development status. This paper analyzes the real-time transport protocol to study a number of issues which associated with reliable real-time transmission, including audio and video data compression and decompression, transmission protocol encapsulation header format. SMPTE ST2022 defines the encapsulation formats and transmission standards of professional baseband IP video signal. To achieve SDI over IP technology, it has to convert SDI signal into data and network environment, so that it can establish comprehensive network transmission and data error correction protocol.

For high speed and long haul direct detection optical transmission systems, low chirp transmitters are necessary to avoid waveform degradation from fiber chromatic dispersion. Recent progress in optical amplifier technology1 has further increased the importance of low chirp transmitters, and optical data transmission over long distances is now possible using optical amplifiers. Thus the problem of fiber chromatic dispersion is more serious. Transmission using conventional direct intensity modulation by semiconductor lasers becomes increasingly difficult, because the chirping of the wavelength restricts the tolerable dispersion to a small value.

The proliferation of a Colorless and Directionless and Contentionless (CD and C) architecture in metro core networks is rising up ever-greater demands on optical amplifiers to be smaller and higher integration. we overview recent advances in optical amplifier technologies, multiple EDFA arrays for compensating loss of a multicast switch and switchable gain EDFAs supporting a wide range of fiber-span loss distributions in the network and focus on the embedded passive component and pump laser in the amplifiers. We will also focus on the pluggable small form factor EDFA amplifies optical signals to enable long Hybrid Fiber Coaxial (HFC) links and amplifier for CFP-DCO/CFP2-ACO transceiver. Finally, we will discuss the feasibility of L-band amplifier and distribution Raman amplifier in a short-haul systems to realize a requisite optical signal to noise ratio (OSNR) to support high bit rate transmission beyond 100G and high capacity transmission.

Polarization effects such as polarization mode dispersion (PMD) and polarization dependent loss (PDL) have become the critical limiting factors for long haul high bit rate optical fiber transmission. This paper use waveplate models to simulate the statistical performance of optical link with PMD and PDL in 40Gbit/s optical system. Three DPSK modulation formats are compared each other for their tolerance against PMD and PDL. The 33% RZ-DPSK is superior to the other two DPSK formats, the 50% RZ-DPSK and the CSRZ-DPSK whose duty cycle is 67% when only PMD is considered. And in case of PDL, the outages for three DPSK formats do not show obvious changes with the increasing of PDL. Furthermore, the performance of two RZ-DPSK formats, whose duty cycles are 33% and 50% respectively, is superior to that of CSRZ-DPSK. This shows that modulation format with narrower pulse width owns more high tolerance against PMD and PDL, therefore the CSRZ-DPSK format shows poorer performance when it is compared with the other two DPSK formats.

Very short range (VSR) high bit rate optical fiber communications are an emerging market dedicated to local area networks, digital displays or board to board interconnects within real time calculators. In this technology, a very fast way to exchange data with high noise immunity and low-cost is needed. Optical multimode graded index fibers are used here because they have electrical noise immunity and are easier to handle than monomode fibers. 850 nm VCSEL are used in VSR communications because of their low cost, direct on-wafer tests, and the possibility of manufacturing VCSEL arrays very easily compared to classical optical transceivers using edge-emitting laser diodes. Although much research has been carried out in temperature modeling on VCSEL emitters, few studies have been devoted to characterizations over a very broad range of temperatures. Nowadays, VCSEL VSR communications tend to be used in severe environments such as space, avionics and military equipments. Therefore, a simple way to characterize VCSEL emitters over a broad range of temperature is required. In this paper, we propose a complete characterization of the emitter part of 2.5 Gb/s opto-electrical transceiver modules operating from -40°C to +120°C using 850 nm VCSELs. Our method uses simple and semi-automatic measurements of a given set of chosen device parameters in order to make fast and efficient simulations.

We demonstrate a tunable Eibium doped fiber ring laser in which an intra-cavity 1×2 electro-optic modulator acts as harmonic mode-locker and adjustable output coupler. We generate stable 7 ps soliton laser pulses at 2.4 GHz, tunable between 1530 and 1565 nm. The pulses are very nearly transform limited with an approximately hyperbolic secant shape both in time and frequency.

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text C. Knöll, M. Gölles, and F. Lederer, "NOISE SUPPRESSION IN SOA TRANSMISSION LINES," in Nonlinear Guided Waves and Their Applications, OSA Technical Digest (Optical Society of America, 1999), paper ThD5. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

Continuous improvement of high bit rate fiber optic networking up to 40 Gb/s, results in increased demand for III/V ICs offering ever lower current input noise, higher output voltage swing, lower jitter and lower DC power consumption. Using production E/D and power sub 0,2 μm GaAs PHEMT processes, transimpedance amplifiers have been developed enabling optical input sensitivity as good as -25 dBm at 2.5 Gb/s and -20 dBm at 40 Gb/s. Similarly laser and modulator drivers have been fabricated with jitter as low as 1,8 ps rms at 10 Gb/s and over 7 V output swing up to 40 GHz. Future generations of products will be implemented using sub 0,1 μm processes based on E/D and power GaAs MHEMTs as well as InP HEMTs maintaining a long tern performance edge over the Silicon counterparts.

Significant improvements in the area of long distance and high bit rate single-mode fiber optical communication systems appear to be possible with heterodyne detection. The SNR could be increased by 10-20 dB depending on the modulation format.1 A heterodyne system requires high stability of the frequency difference between the emitter and the local oscillator. Only slow drifts can be reduced by controlling the laser diode (LD) temperature.2,3 However, if FSK or coherent PSK modulation are to be fully exploited (as they give the best performance), a high short-term stability is required (~2 MHz peak to peak1). On the other hand, it would be desirable to directly modulate the LD to avoid the use of an external modulator.

A requirement-specific decoder design for forward error-correction in 2 Gbps optical fiber communication system is presented. Low-density parity-check codes are used to achieve high bit error rate performance. Several novel error-decoding architectures are proposed and their design configurations explored to identify optimal cost/performance design. Serial, parallel and scalable architectures are studied. The result is a scaleable architecture that consists of 1.3 million CMOS gates running at 295 MHz and it achieves a throughput of 2.51 Gbps.