Time Division Multiplexing Transmission Research Articles

An all-optical bit-error indicating scheme based on self-phase modulation and filtering

In this paper, a novel all-optical bit-error indicating scheme is numerically studied. The bit-error indicating function is achieved by two all-optical processing stages. Firstly, the amplified original bit stream propagates through a high-nonlinear fiber and experiences self-phase modulation which causes intensity-dependent spectrum broadening and split. And then, the bit stream output from the high-nonlinear fiber is filtered by a band-pass filter with the same central wavelength as the original bit stream to generate an error bit indicating signal. The error bit indicating signal, in which only the “Error” bits have the highest peak power, is synchronous with the delayed original bit stream. Therefore, the position of the “Error” bits in the original bit stream can be identified by setting only one judge threshold in the error bit indicating signal. The scheme is demonstrated for an 80 Gb/s bit stream with return-to-zero format by simulation. The results show that the scheme can be used for the all-optical bit-error indicating of the super high bit-rate systems using the return-to-zero format which is favored in the optical time division multiplexing transmission systems.

Ultrahigh-Speed OTDM-Transmission Technology

This paper reviews ultrahigh-speed data transmission in optical fibers based on optical time division multiplexing (OTDM) transmission technology. Optical signal processing in the transmitter and receiver as well as the requirements on ultrahigh-speed data transmission over a fiber link are discussed. Finally, results of several OTDM-transmission experiments, including 160-Gb/s transmission over 4320 km, 1.28-Tb/s transmission over 240 km, and 2.56-Tb/s transmission over 160-km fiber link, are described

Wireless multichannel biopotential recording using an integrated FM telemetry circuit

This paper presents a four-channel telemetric microsystem featuring on-chip alternating current amplification, direct current baseline stabilization, clock generation, time-division multiplexing, and wireless frequency-modulation transmission of microvolt- and millivolt-range input biopotentials in the very high frequency band of 94-98 MHz over a distance of approximately 0.5 m. It consists of a 4.84-mm2 integrated circuit, fabricated using a 1.5-microm double-poly double-metal n-well standard complementary metal-oxide semiconductor process, interfaced with only three off-chip components on a custom-designed printed-circuit board that measures 1.7 x 1.2 x 0.16 cm3, and weighs 1.1 g including two miniature 1.5-V batteries. We characterize the microsystem performance, operating in a truly wireless fashion in single-channel and multichannel operation modes, via extensive benchtop and in vitro tests in saline utilizing two different micromachined neural recording microelectrodes, while dissipating approximately 2.2 mW from a 3-V power supply. Moreover, we demonstrate successful wireless in vivo recording of spontaneous neural activity at 96.2 MHz from the auditory cortex of an awake marmoset monkey at several transmission distances ranging from 10 to 50 cm with signal-to-noise ratios in the range of 8.4-9.5 dB.

High-speed optical signal processing using semiconductor optical amplifiers

The authors report on all-optical switching devices based on semiconductor optical amplifiers (SOA) in applications for optical time division multiplexing (OTDM) transmission technology. The report includes a discussion on the basic properties of an SOA, on the nonlinear processes of cross-phase modulation and four-wave mixing in the SOA used for all-optical switching, and on the application of the SOA as demultiplexer, add-drop multiplexer, clock recovery and wavelength converter. The devices considered here operate at data rates in excess of \Gb80, where electrical signal processing is not available today.

A Study on Forward Link Capacity in MC-CDMA Cellular System with MMSEC Receiver

This paper focuses on the MC-CDMA (Multi Carrier-Code Division Multiple Access) with the MMSEC (Minimum Mean Square Error Combining) receiver, which is a good candidate of a transmission scheme for beyond 3G systems. This paper evaluates the forward link capacity using the MMSEC receiver in the MC-CDMA cellular system, which employs TDM (Time Division Multiplex) transmission for multiple users. In this paper, the PDF (Probability Distribution Function) of the SINR (Symbol to Interference plus Noise energy Ratio) after MMSEC under multi-cell environment are calculated with the various number of the code division multiplexes. Based on the PDF, the numerical relation can be derived between the peak rate of the adaptive transmission and the average transmission rate per sector.

Design of a remote lighting control system using time division multiplex transmission

Design of a remote lighting control system using time division multiplex transmission

A SiGe HBT IC CHIPSET for40-Gb/s OPTICAL TRANSMISSION SYSTEMS

Using a 0.2-μm self-aligned epitaxial-growth silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) technology, we have developed a chipset for 40-Gb/s time-division multiplexing optical transmission systems. In this paper, we describe seven analog and digital ICs: a 45-GHz bandwidth transimpedance amplifier, a 48.7-GHz bandwidth automatic-gain-controllable amplifier, a 40-Gb/s decision circuit, a 40-Gb/s full-wave rectifier, a 40-Gb/s limiting amplifier with a 32-dB gain, a 45-Gb/s 1:4 demultiplexer, and a 45-Gb/s 4:1 multiplexer. To increase bandwidth of the transimpedance amplifier, a common-base input stage is introduced. In order to have high gain and wide bandwidth simultaneously, active load circuits composed of a differential transimpedance amplifier are used for the AGC amplifier, the limiting amplifier, and the decision circuit. Full-rate clocking is employed to reduce the influence caused by clock-duty variation in digital circuits such as the decision circuit, the demultiplexer, and the multiplexer. All ICs were characterized by using on-wafer probes, and some of them were built in brass-packages for bit-error rate measurement.

Impact of fiber chromatic dispersion in high-speed TDM transmission systems

General guidelines for high-speed time-division multiplexing (TDM) data-rate transmission are essential for the increase of the overall transmission capacity. In this paper, general theoretical investigations concerning fiber chromatic dispersion in optical TDM systems are performed. Recent experiments that confirm the theoretical predictions are presented. Nonzero dispersion-shifted fiber and standard single-mode fiber are recommended for 40 and 160 Gb/s, respectively, independent of the chromatic dispersion compensation scheme.

Interferometric noise in optical time division multiplexing transmission system

A theoretical assessment of the interferometric noise in the optical time division multiplexing (OTDM) transmission system is presented. The impact of such noise on the system performance were investigated in detail. The corresponding system requirements were also revealed by the calculation results. Recommendations on the use of prechirping to reduce the interferometric noise in the OTDM system are given.

Effects of pulse chirp on supercontinuum produced in dispersion decreasing fibre

The supercontinuum (SC) source plays a key role in wavelength division multiplexing over the optical time division multiplexing (WDM/OTDM) transmission system. The SC produced in dispersion decreasing fibre (DDF) is wider and flatter than that produced in dispersion shifted fibre (DSF). In this paper, a SC producing process in DDF is numerically simulated, the effects of pump pulse chirp on the SC width and flatness are initially studied and the corresponding theoretical explanations are given. Particularly, we have analysed and compared the evolutions of the SC along DDF pumped by different chirp pulses. Several valuable conclusions are obtained.

Ultrahigh-speed optical time-division multiplexing transmission (OPN Trends Supplement)

Ultrahigh-speed optical time-division multiplexing transmission (OPN Trends Supplement)

Receiver performance analysis and basic design for optical time‐division multiplexed transmission systems

The characteristics of the receiver used for an optical time-division multiplex transmission system are studied from the signal-to-noise ratio point of view. The receiver, which is characterized by having an optical time-division demultiplexing circuit, has so far been the subject of experimental and analytical discussion only regarding the characteristics of the optical demultiplexing circuit. Taking into account the signal pulse width of the received signal and the frequency bandwidth of the baseband circuit in addition to the optical demultiplexing circuit, we derive the expression of the signal-to-noise ratio, resulting in a systematic analysis of the receiver, which has never before been attempted. For the receiver with an optical time-division demultiplexing circuit, the optimum and allowable baseband bandwidth are quantitatively presented in terms of the signal pulse width and the optical noise power. This provides basic guidelines of receiver design. For instance, when a 20 Gbit/s signal with a 20-ps pulse width is optically demultiplexed into 10 Gbit/s, with a rectangular optical gate, the optimum baseband width is 6.3 GHz. Even for different pulse widths, this bandwidth exhibits signal-to-noise ratio degradation of 1 dB or less in comparison to the receiver with an optimized bandwidth. Furthermore, the requirements for the modulation depth and the width of the optical gate, as well as the phase difference between the optical gate and the signal pulse are discussed. © 1999 Scripta Technica, Electron Comm Jpn Pt 1, 83(4): 93–104, 2000

Ultrahigh-speed long-distance TDM and WDM soliton transmission technologies

Recent progress on time-division multiplexed (TDM) and wavelength-division multiplexed (WDM) soliton transmission is described, in which dispersion management (DM) plays an important role in increasing the power margin and the dispersion tolerance. The characteristics of the DM soliton are compared with those of return-to-zero (RZ) and nonreturn-to-zero (NRZ) pulses. With a small dispersion swing, the system can still be described as an average soliton with a nonlinear Schrodinger equation (NLSE), whereas with a large dispersion swing, the soliton-like steady-state pulse becomes a chirped Gaussian pulse, in which the master equation is closer to a linear Schrodinger equation (LSE) with a parabolic potential well. An in-line modulation scheme up to 80 Gb/s per channel and its two-channel WDM transmission over 10000 km are described. A 640-Gb/s (40 Gb/s/spl times/16 channels) WDM soliton transmission over 1000 km is also reported with a DM single-mode fiber, without the use of in-line modulation. Finally, dark soliton transmission at 10 Gb/s over 1000 km is described as a different nonlinear pulse application.

SiGe driver circuit with high output amplitude operating up to 23 Gb/s

A high-speed driver circuit is presented with special regard to layout aspects. The IC, which was fabricated in an advanced SiGe bipolar technology, was developed for driving external modulators in a 20 Gb/s fiber-optic time division multiplex transmission system but can also be used as an output stage of multipurpose pulse generators. Measurements on mounted chips show clear eye diagrams up to 23 Gb/s data rate and high single-ended and differential output swings of 3.5 and 7 V/sub p-p/, respectively, at 50 /spl Omega/ external load. To the best of the authors' knowledge, this is the highest voltage swing reported so far for a silicon-based driver circuit at comparable operating speed.

40-Gbit/s TDM transmission technologies based on ultra-high-speed ICs

This paper presents 40-Gbit/s time division multiplexing (TDM) transmission technologies based on 0.1-/spl mu/m-gate-length InP high electron mobility transistor IC's and a scheme for upgrading toward a terabit-per-second capacity system. A 40-Gbit/s, 300-km, in-line transmission experiment and a dispersion-tolerant 40-Gbit/s duobinary transmission experiment are described as 40-Gbit/s single carrier system applications on dispersion-shifted fiber. An ultra-high-speed receiver configuration using a high-output-power photodiode is introduced to realize fully electrical receiver operation beyond 40 Gbit/s. The high-sensitivity operation of the optical receiver (-27.6 dBm@BER=10/sup -9/) is demonstrated at a data bit rate of 50 Gbit/s for the first time using a unitraveling carrier photodiode. A dense wavelength division multiplexing (DWDM) system operating up to terabits per second can be easily realized on a zero-dispersion flattened transmission line using ultra-high speed TDM channels of 40 Gbit/s and beyond. An experiment demonstrates 1.04-Tbit/s DWDM transmission based on 40-Gbit/s TDM channels with high optical spectrum density (0.4 bit/s/Hz) without dispersion compensation.

Ultrahigh-speed optical time-division-multiplexed transmission technology based on optical signal processing

Recent progress in optical time-division-multiplexed (TDM) transmission technologies is reviewed including optical short pulse generation, time-division multiplexing/demultiplexing, timing extraction, and waveform measurement. The latest 400-Gbit/s transmission experiments based on optical signal processing are presented and the possibility of terabit/second TDM transmission is discussed.

Ultrahigh-bit-rate optical transmission research in Japan

Recent progress toward ultrahigh-bit-rate optical fibre transmission systems employing optical time-division multiplexing (TDM) techniques is reviewed. Focus is placed on 100 Gbit s$^{-1}$ optical TDM transmission systems and the related technologies studied in Japan. Successful 100 Gbit s$^{-1}$ TDM transmission experiments over 200-500 km and the key technologies are described, including ultrashort optical pulse generation, all-optical multiplexing-demultiplexing and optical timing extraction techniques, together with state-of-the-art performances and future prospects.

Quasi-orthogonal subcarrier multiplexing for high-capacity optical data links

Short-reach interconnect requirements in digital computers and telephone switches may require throughputs of 10 Gb/s (50 parallel lines at 200 Mb/s each) in the near future. Time-division multiplexing (TDM) baseband transmission methods require high-speed multiplexing and precise clock recovery, and/or multiple fibres for such applications. As an alternative, the authors propose and analyze a quasi-orthogonal subcarrier multiplexing technique (QO-SCM) for short-reach digital fibre-optic interconnect applications. QO-SCM signal processing exploits the symbol-time synchronism which is inherent among the parallel lines of a typical data bus, to permit simplified filtering and higher spectral efficiency than conventional SCM. One can achieve bandwidth efficiencies of up to 2 b/s/Hz while eliminating RF channel filters and guard bands, and requiring only simple baseband pulse shaping. Link performance is studied through simulation to derive worst-case noise margins for a 50-channel QO-SCM pay-load signal with 10 Gb/s total capacity using a numerical model of the laser rate equations. Results predict that 10 Gb/s could be transmitted over 100 m at a bit error rate (BER) ≤10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-12</sup> on a single fibre-optic link, given a laser RIN of -155 dB/Hz.

Performance models of statistical multiplexing in packet video communications

Models and results are presented that assess the performance of statistical multiplexing of independent video sources. Presented results indicate that the probability of buffering (or delaying) video data beyond an acceptable limit drops dramatically as the number of multiplexed sources increases beyond one. This demonstrates that statistical or asynchronous time-division multiplexing (TDM) can efficiently absorb temporal variations of the bit rate of individual sources without the significant variations in reception quality exhibited by multimode videocoders for synchronous TDM or circuit-switched transmission. Two source models are presented. The first model is an autoregressive continuous-state, discrete-time Markov process, which was used to generate source data in simulation experiments. The second model is a discrete-state, continuous-time Markov process that was used in deriving a fluid-flow queuing analysis. The presented study shows that both models generated consistent numerical results in terms of queuing performance. >

Protocol for packet/circuit switch interworking

Packet and circuit network integration and interworking issues are discussed, and a method for realization of interworking with existing digital circuit switched networks is proposed. The method is based on the use of time division multiplex transmission media, digital and analogue access and the use of a new protocol. It is concluded that the benefits of interworking can be achieved with minimal disruption to the circuit switched network.