The Experts below are selected from a list of 2835 Experts worldwide ranked by ideXlab platform

Koichi Ishihara - One of the best experts on this subject based on the ideXlab platform.

Y C Chung - One of the best experts on this subject based on the ideXlab platform.

  • chromatic dispersion monitoring technique using Pilot Tone carried by broadband light source
    IEEE Photonics Technology Letters, 2009
    Co-Authors: Hyunhwan Choi, Paul K J Park, Y C Chung
    Abstract:

    We propose and demonstrate a simple chromatic dispersion monitoring technique based on the Pilot Tone generated by a broadband light source (BLS). Previously, the Pilot Tone has been obtained by directly modulating each transmitter laser with a small sinusoidal current. Thus, for use in the wavelength-division- multiplexed (WDM) network, each transmitter should be modulated with a unique Pilot Tone. However, we obtain the Pilot Tone by modulating an additional BLS such as a reflective semiconductor optical amplifier. Thus, there is no need to modulate each transmitter laser. We evaluate the performance of the proposed technique in an 8 times10 Gb/s WDM system. The result shows that, unlike the conventional Pilot-Tone-based monitoring technique, the performance of this technique is almost insensitive to the polarization-mode dispersion.

  • performance analysis of low frequency Pilot Tone based monitoring techniques in amplified wavelength division multiplexed networks
    Optical Engineering, 2008
    Co-Authors: Paul K J Park, Y C Chung
    Abstract:

    In amplified wavelength-division-multiplexed (WDM) networks, the performance of a low-frequency (<100 kHz) Pilot-Tone-based monitoring technique could be deteriorated by the slow dynamic properties of erbium-doped fiber amplifiers (EDFAs). We develop a simple model to describe this effect and estimate the maximum size of WDM network that the Pilot-Tone-based monitoring technique could support. The result shows that 100-kHz Pilot Tones could be used for the cost-effective monitoring of metro optical networks (32 channels, 320-km transmission).

  • Pilot Tone based wdm monitoring technique for dpsk systems
    IEEE Photonics Technology Letters, 2006
    Co-Authors: Paul K J Park, Y C Chung
    Abstract:

    To evaluate the effectiveness of the Pilot-Tone-based monitoring technique in differential phase-shift keying (DPSK) systems, we measure the mutual interactions between the Pilot Tones and DPSK signals and compare the results with those of on-off keying (OOK) signals. The results show that, by using the DPSK format instead of OOK, it is possible to increase the number of wavelength-division-multiplexed channels that can be monitored simultaneously by using Pilot Tones without using optical demultiplexers by more than one hundred times

  • effects of stimulated raman scattering on Pilot Tone based wdm supervisory technique
    IEEE Photonics Technology Letters, 2000
    Co-Authors: H.s. Chung, S.k. Shin, Keun Joo Park, Y C Chung
    Abstract:

    We report on the effects of stimulated Raman scattering (SRS) on the Pilot-Tone-based wavelength-division-multiplexing (WDM) monitoring technique. The SRS-induced ghost Tones were measured after compensating the effects of erbium-doped fiber amplifiers (EDFA's) slow gain dynamics. Using these results, we estimated the maximum size of WDM network that the Pilot-Tone based monitoring technique could support.

Takayuki Kobayashi - One of the best experts on this subject based on the ideXlab platform.

  • experimental analysis of lte signals in wdm pon managed by embedded Pilot Tone
    IEEE Photonics Technology Letters, 2017
    Co-Authors: Kazuaki Honda, Takayuki Kobayashi, Tatsuya Shimada, Jun Terada, Susumu Nishihara, Akihiro Otaka
    Abstract:

    Dense deployment of many small cells is one promising solution to cope with mobile traffic increases. However, the deployment needs many optical fibers and network operators require efficient management for these cells. To overcome these issues, we have proposed a WDM-PON system managed by an electrically embedded Pilot Tone and confirmed its feasibility. In this letter, we compare management methods and clarify 128-kb/s Pilot Tone parameters that negligibly affect LTE signals transported by CPRI option seven experimentally. The results show that the modulation index as high as 20% and carrier frequency as high as 5 MHz are suitable under 1.0-dB optical power penalty.

  • wdm passive optical network managed with embedded Pilot Tone for mobile fronthaul
    European Conference on Optical Communication, 2015
    Co-Authors: Kazuaki Honda, Takayuki Kobayashi, Tatsuya Shimada, Jun Terada, Akihiro Otaka
    Abstract:

    A WDM-PON system managed with an electrically embedded Pilot Tone to accommodate mobile fronthaul is proposed. Experimental results show a 128 kb/s Pilot Tone can be inserted into the low frequency area of CPRI signals with negligible insertion penalty.

  • Nonlinear tolerant long-haul WDM transmission over 1200km using 538Gb/s/ch PDM-64QAM SC-FDM signals with Pilot Tone - OSA Technical Digest
    Optical Fiber Communication Conference, 2012
    Co-Authors: Takayuki Kobayashi, Akihide Sano, Akihiko Matsuura, Yutaka Miyamoto, Koichi Ishihara
    Abstract:

    e investigate long-haul WDM transmission using 538Gb/s PDM-64QAM single-carrier frequency-division-multiplexing (SC-FDM) signal with Pilot Tone. Assuming 20% FEC overhead, the longest transmission distance of 1200km at the spectral efficiency of 8.96b/s/Hz is achieved.

  • Nonlinear tolerant spectrally-efficient transmission using PDM 64-QAM single carrier FDM with digital Pilot-Tone
    Journal of Lightwave Technology, 2012
    Co-Authors: Takayuki Kobayashi, Akihide Sano, Akihiko Matsuura, Yutaka Miyamoto, Koichi Ishihara
    Abstract:

    We propose nonlinear tolerant single carrier frequency-division-multiplexing (SC-FDM) signal enhanced by digital Pilot-Tone for future high speed Ethernet transport like 400 G Ethernet. First, we discuss system configuration and the wavelength-division-multiplexed (WDM) transmission of SC-FDM signals employing polarization-division-multiplexed (PDM) 64-ary quadrature amplitude modulation (64-QAM). Next, we describe the long-haul transmission characteristics of 50 GHz-spaced 538 Gb/s × 7 ch WDM signals. We compare digital back-propagation (DBP) and digital Pilot-Tone for nonlinearity compensation and experimentally show that digital Pilot-Tone can effectively compensate the phase noise induced by inter-channel nonlinear effects with less computational complexity than DBP. Then we discuss a high-capacity transmission experiment employing 548 Gb/s PDM-64QAM SC-FDM; 102.3 Tb/s (224 × 548 Gb/s) C- and extended L-band WDM transmission is demonstrated over 240 km (3 × 80 km) of pure-silica-core fiber (PSCF) with all-Raman amplification. Thanks to the high nonlinear tolerance enhanced by Pilot-Tone, we can employ the 80 km repeater spacing used in conventional terrestrial systems. Assuming 20% forward error correction (FEC) overhead, a spectral efficiency of 9.1 b/s/Hz is achieved.

Akihide Sano - One of the best experts on this subject based on the ideXlab platform.

Magnus Karlsson - One of the best experts on this subject based on the ideXlab platform.

  • experimental investigation of link impairments in Pilot Tone aided superchannel transmission
    IEEE Photonics Technology Letters, 2019
    Co-Authors: Mikael Mazur, Abel Lorencesriesgo, Magnus Karlsson, Jochen Schroeder, P A Andrekson
    Abstract:

    We investigate the performance of single-Pilot-Tone locked frequency comb-based superchannel transmission for distances up to 1200km. In our scheme, electro-optic transmitter and receiver combs are locked by leaving one of the transmitter carriers unmodulated and regenerating the receiver comb via optical injection locking. This approach significantly reduces carrier offsets and therefore leads to reduced digital signal processing complexity. We experimentally assess how transmission impairments such as noise added by optical amplifiers and fiber nonlinearities affect the quality of the comb regeneration. Our results show that while the operating conditions are more stringent at longer distances, the single Pilot is robust to impairments. At optimal launch power, similar performance with respect to an intradyne receiver is observed, showing that the optical Pilot Tones can be co-transmitted with data channels even at distances spanning hundreds of kilometer. The total superchannel spectral efficiency (throughput), including the Pilot Tone and guardbands, is 9.6 bits/s/Hz (12 Tbit/s) after 480 km and 8.4 bits/s/Hz (10.5 Tbit/s) after 960km.

  • 10 tb s pm 64qam self homodyne comb based superchannel transmission with 4 shared Pilot Tone overhead
    Journal of Lightwave Technology, 2018
    Co-Authors: Mikael Mazur, Abel Lorencesriesgo, Jochen Schroder, P A Andrekson, Magnus Karlsson
    Abstract:

    We demonstrate transmission of a comb-based 10 Tb/s 50 $\times$ 20 Gbaud PM-64QAM superchannel using frequency comb regeneration to reduce carrier offsets and allow for self-homodyne detection. The regeneration is enabled by transmitting two optical Pilot Tones which are filtered and recovered in the receiver using optical injection locking and an electrical phase-locked loop. We show that by utilizing frequency combs together with optical Pilot Tones, self-homodyne detection similar to systems using one Pilot Tone per wavelength channel, can be achieved. Sharing the overhead for Pilot Tones reduces the complexity and limits the overhead to 4%. This enabled a total superchannel spectral efficiency of 7.7 b/s/Hz. To evaluate the performance, we perform both back-to-back measurements and transmission over 80 km of standard single-mode fiber. Successful self-homodyne detection of all 50 data channels in the 10-nm-wide superchannel demonstrates that the spectral coherence from frequency combs, combined with the use of optical Pilots, can overcome limitations arising from frequency offset and phase noise in high-order QAM transmission while keeping the Pilot overhead low.

  • high spectral efficiency pm 128qam comb based superchannel transmission enabled by a single shared optical Pilot Tone
    Journal of Lightwave Technology, 2018
    Co-Authors: Mikael Mazur, Abel Lorencesriesgo, Jochen Schroder, P A Andrekson, Magnus Karlsson
    Abstract:

    We exploit the coherence of frequency combs for high spectral efficiency superchannel transmission via effective sharing of a single Pilot Tone. By phase-locking the receiver comb to the transmitted Pilot Tone, carrier offsets are suppressed while both the overhead and complexity associated with the Pilot Tone are reduced. We form a 55 carrier superchannel using a 25-GHz spaced electro-optic frequency comb seeded by a 100-kHz linewidth laser. At a Pilot Tone overhead of $ 2%, the reduction in carrier offsets is shown to facilitate blind DSP-based carrier recovery of all 54 $\times$ 24 Gbaud PM-128QAM data channels. The resulting superchannel spectral efficiency is 10.3 bits/s/Hz assuming a 28% overhead for forward error correction. Our results show the potential for optical Pilot Tones to reduce both overhead and complexity in systems using comb-based superchannels together with high-order modulation formats.