Rolands Parts

Investigation on Maximum Available Reach for Different Modulation Formats in WDM-PON Systems

Abstract Considering the growing demand for broadband of access networks, in the present paper we investigate various modulation formats as a way of increasing the performance of optical transmission systems. Non-return-to-zero (NRZ) on-off keying, return-to-zero (RZ) OOK, carrier suppressed RZ (CSRZ) OOK, duobinary (DB), NRZ differential phase shift keying (NRZDPSK), RZ-DPSK and CSRZ-DPSK formats are compared using the maximal achievable reach with bit error rate less than 10−9 as a criterion. Simulations are performed by using OptSim software tool. It is shown that using the transmission system without dispersion compensation the best results are shown by duobinary and CSRZ-OOK modulation formats, but with the system using dispersion compensating fiber (DCF) the longest transmission distance is achieved by RZ-DPSK modulation format. By investigating the influence of channel spacing for best-performed modulation formats, network reach decrease for transmission systems with DCF fiber has been observed due to channel crosstalk.

Impact of cascaded MRRs on all-optical clock recovery from 40 Gbit/s RZ-OOK signal

An all-optical clock recovery has been demonstrated numerically with single and double ring microring resonators from 40 Gbit/s return-to-zero on-off keying optical signal. The influence of device cascadability on amplitude fluctuation caused by patterning effects of extracted clock values have been evaluated. Open source simulation toolbox Optilux was used for simulations. The results show that these fluctuations related to patterning effects are considerably reduced after processing with five cascaded single ring microring resonators.

Extended reach 32-channel dense spectrum-sliced optical access system

In this paper, we report on 32-channel dense wavelength division multiplexed passive optical network (WDM-PON) with shared amplified spontaneous emission (ASE) light source. Proposed transmission system enables to simplify the architecture of PON network and has a dense channel spacing of 50 GHz as well as it is fully compatible with ITU-TG.694.1 DWDM frequency grid. We investigated the performance of next generation passive optical network (NG-PON) compatible dense spectrum sliced WDM-PON system (SS-WDM PON) with 32 directly modulated 10 Gbit/s channels located in the optical C band. It is shown that maximal transmission distance for SS-WDM PON system can be increased by 23.8% if standard SMF fiber is being replaced with NZ-DSF fiber. Post FEC error free transmission has been demonstrated for all 32 channels over different optical fiber types (SMF and NZ-DSF) and line lengths of at least 100 km.

Demonstration of a dual-pump FOPA based 48 channel multicarrier optical source for WDM transmission systems

In this paper the authors demonstrate a model of a multicarrier light source for wavelength division multiplexed transmission systems, where two dual-pump fiber optical parametric amplifiers are used to increase the number of initial carriers three times. The optical radiation of the 16 initial carriers is combined and afterwards divided among the two parametric amplifiers, which are placed in parallel in the scheme. Each amplifier is responsible for generating 16 additional carriers that afterwards will be used as transport for the informative signal. The proposed multicarrier source solution allows to produce 48 carriers with 100 GHz channel spacing and with power non-uniformity below 2 dB among all the channels at the output of the transmitter.

Evaluation of the maximum permissible transmission distance for the mixed-HDWDM systems

The authors have evaluated the maximum permissible transmission distance for the purposed configuration of mixed-HDWDM system that is offered as model for the designing of next generation of an optical transport networks. In general, the investigated mixed-WDM FOTS can be represented using the following configuration scheme: [1st, 4th and 7th channels: NRZ-OOK, R= 10 Gbit/s] - [2nd (fc = 193.1 THz), 5th and 8th channels: 2-POLSK, R=40 Gbit/s] - [3rd, 6th and 9th channels: NRZ-DPSK, R=40 Gbit/s]. This is the “pessimistic scenario” since secures the highest in systems channel detected signals bit-error-rate as compared with other possible bitrate distribution among the channels. The maximum distance reach was evaluated using iteration loops consisted of chromatic dispersion compensation module (DCM), optical signal inline amplifier (based on EDFA) and one span of standard single mode fiber (SSMF, ITU-T Rec. G.652 D). One such loop emulates one sector of a fiber-optic transmission line (FOTL) over which the optical signals can be transmitted and then successfully detected on the other fiber end with appropriate error probability below the maximum permissible threshold. It is found out and analysed the correlation between the maximum distance reach and the investigated systems average spectral efficiency and the length of used SSMF span.