scispace - formally typeset

Journal ArticleDOI

168-Gb/s all-optical wavelength conversion with a symmetric-Mach-Zehnder-type switch

01 Oct 2001-IEEE Photonics Technology Letters (IEEE)-Vol. 13, Iss: 10, pp 1091-1093

AbstractError-free all-optical wavelength conversion at 168 Gb/s, which is the highest repetition rate ever reported, has been achieved by using a symmetric-Mach-Zehnder (SMZ)-type switch. Low-power-penalty 84-Gb/s operation is also demonstrated. The push-pull switching mechanism of the SMZ switch enables such ultrafast operation based on cross-phase modulation associated with the carrier depletion in a semiconductor optical amplifier. The configuration of the delayed-interference signal-wavelength converter, which is a simplified variant of the SMZ switch, is used in this experiment.

Topics: Optical switch (61%), Optical amplifier (51%)

Summary (1 min read)

I. INTRODUCTION

  • T HE SCHEME of ultrafast optical networks based on optical-time-division multiplexing (OTDM) technology attracts much attention in terms of not only high capacity but also high flexibility.
  • In such networks, the expected bit rates per wavelength channel are over 100 Gb/s, and thus various signal processing at these ultrahigh bit rates will be done in the optical domain.
  • Recently, error-free 168-Gb/s DEMUX with the hybrid-integrated SMZ (HI-SMZ) switch [7] has also been demonstrated.
  • To utilize the SMZ switches for a wider range of applications such as logic, regeneration [8] , or wavelength conversion [9] , operation excited by higher repetition data-modulated optical pulses is required on top of being ultrafast.
  • The wavelength converter operates without logic inversion and keeps the pulse duration almost unchanged from input to output.

II. EXPERIMENTAL SETUP

  • The experimental setup for 168-Gb/s wavelength conversion is shown schematically in Fig. 1 .
  • The 168-Gb/s signal pulses were generated by modulating the output of the fiber laser with a pseudorandom bit sequence (PRBS) with a length of 2 and then passively multiplexing the modulated pulses.
  • The average powers of the signal pulses and of the CW light at the input of the SOA module were 10 and 16 dBm, respectively.
  • The time delay provided by the birefringence of the calcite was set to 2.0 ps, which determined the duration of the output pulse.
  • Thus, the pulse duration was kept almost unchanged before and after wavelength conversion.

III. RESULTS AND DISCUSSION

  • Fig. 2(a) shows the 168-Gb/s output waveform of the DISC measured by a streak camera.
  • The trace was recorded as the accumulation of many PRBS pulses, and thus was observed as a regular pulse sequence.
  • For 84-Gb/s operation, the power penalty for MUX and DEMUX was estimated to be about 2.5 dB from a separate experiment [7] .
  • These power penalties for wavelength conversion are mainly due to a residual pattern effect induced in the SOA by the data-modulated signal pulses.
  • The mechanism of suppressing the pattern effect by using the relatively high average power of the CW light is interpreted by the effective reduction in the carrier lifetime of the SOA [4] , [12] .

IV. CONCLUSION

  • The authors have achieved error-free all-optical wavelength conversion at 168 Gb/s, which is the highest repetition rate ever reported, with the Delayed Interference Signal-wavelength Converter.
  • Low-power-penalty 84-Gb/s operation has also been achieved.
  • The authors believe that the present operation is more complete than earlier 100-Gb/s-level experiments because the pulse duration is kept nearly unchanged, logic is noninverted, and high extinction ratio output is obtained.

Did you find this useful? Give us your feedback

...read more

Content maybe subject to copyright    Report

IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 13, NO. 10, OCTOBER 2001 1091
168-Gb/s All-Optical Wavelength Conversion With a
Symmetric-Mach–Zehnder-Type Switch
Shigeru Nakamura, Yoshiyasu Ueno, and Kazuhito Tajima
Abstract—Error-free all-optical wavelength conversion at
168 Gb/s, which is the highest repetition rate ever reported, has
been achieved by using a Symmetric-Mach–Zehnder (SMZ)-type
switch. Low-power-penalty 84-Gb/s operation is also demon-
strated. The push–pull switching mechanism of the SMZ switch
enables such ultrafast operation based on cross-phase modula-
tion associated with the carrier depletion in a semiconductor
optical amplifier. The configuration of the Delayed-Interference
Signal-wavelength Converter, which is a simplified variant of the
SMZ switch, is used in this experiment.
Index Terms—All-optical switch, interferometer, nonlinear op-
tics, semiconductor optical amplifier,ultrafast,wavelengthconver-
sion.
I. INTRODUCTION
T
HE SCHEME of ultrafast optical networks based on
optical-time-division multiplexing (OTDM) technology
attracts much attention in terms of not only high capacity but
also high flexibility. In such networks, the expected bit rates
per wavelength channel are over 100 Gb/s, and thus various
signal processing at these ultrahigh bit rates will be done in
the optical domain. In achieving such ultrafast optical signal
processing, the Symmetric-Mach–Zehnder (SMZ) all-optical
switch family, including the original SMZ switch [1], the
Polarization-Discriminating SMZ (PD-SMZ) switch [2], and
the Delayed-Interference Signal-wavelength Converter (DISC)
[3]–[5] is quite promising. These all-optical switches use
essentially the same mechanism to enable high-speed and
high-efficiency switching. Although switching is based on a
refractive index change induced by a carrier density change in
a semiconductor, the push–pull switching mechanism cancels
out the effect associated with slow relaxation of the induced
refractive index change. The applicability of the SMZ switch
family to ultrafast demultiplexing (DEMUX) has already
been verified in various experiments. We have demonstrated
200-fs switching [6], showing the capability of over 1-Tb/s
DEMUX. Recently, error-free 168-Gb/s DEMUX with the
hybrid-integrated SMZ (HI-SMZ) switch [7] has also been
demonstrated. However, to utilize the SMZ switches for a
wider range of applications such as logic, regeneration [8],
or wavelength conversion [9], operation excited by higher
repetition data-modulated optical pulses is required on top of
Manuscript received January 18, 2001; revised June 18, 2001. This work was
supported in part by the Femtosecond Technology Project under the manage-
ment of the Femtosecond Technology Research Association supported by the
New Energy and Industrial Technology Development Organization.
The authors are with System Devices and Fundamental Research, NEC Cor-
poration, 305-8501 Ibaraki, Japan (e-mail: s-nakamura@dy.jp.nec.com).
Publisher Item Identifier S 1041-1135(01)08074-0.
being ultrafast. To date, 100-Gb/s wavelength conversion [10]
and 80-Gb/s pulse regeneration [11] have been shown by using
the push–pull switching mechanism of the SMZ all-optical
switch incorporating semiconductor optical amplifiers (SOAs).
In such operation, the pattern effect due to high repetition
data-modulated signal pulses is suppressed by injecting un-
modulated continuous-wave (CW) light or clock pulses into
SOAs at relatively high average power [4], [12]. Several
experiments [10] exhibiting ultrafast all-optical wavelength
conversion accompanied the conversion from return-to-zero
(RZ) to nonreturn-to-zero (NRZ) and/or logic inversion.
Although such format conversion is also useful depending on
applications, unchanging pulse duration and noninverting logic
would be generally required.
Here, we report on the first error-free 168-Gb/s all-optical
wavelength conversion by using the DISC. Low-power-penalty
84-Gb/s operation is also demonstrated. The results confirm that
the SMZ-type switches can be driven by data-modulated signal
pulses at a bit rate of 160 Gb/s, which is considered to be the
bit rate for the first-generation OTDM system. The wavelength
converter operates without logic inversion and keeps the pulse
duration almost unchanged from input to output.
II. E
XPERIMENTAL SETUP
The experimental setup for 168-Gb/s wavelength conversion
is shown schematically in Fig. 1. The DISC consists of a non-
linear waveguide and a delay line, as detailed in [3]. An SOA
module was usedas the nonlinear waveguide.In the SOA, signal
pulses deplete carriers, and thus give cross-phase modulation to
CW light at another wavelength. At the delay line, the two tem-
porally displaced components of the phase-modulated CW light
interfere, forming a pulse output. In this experiment, the delay
line was composed of a calcite, a Babinet–Soleil phase shifter,
and a polarizer. The duration of the output pulse from the DISC
was determined by the birefringence of the calcite and was un-
restricted by the slow relaxation of the induced nonlinear phase
shift.
The optical source for the signal pulses was an activelymode-
locked fiber laser (PriTel, Inc.) that generated 1.0-ps 1564-nm
pulses at a repetition rate of 10.5 GHz. The 168-Gb/s signal
pulses were generated by modulating the output of the fiber
laser with a pseudorandom bit sequence (PRBS) with a length
of 2
and then passively multiplexing the modulated pulses.
To obtain uniformly multiplexed signal pulses, we used two-
stage fiber-based delay lines and two-stage spatial delay lines,
where the intensities and intervals of multiplexed pulses were
adjustable. These 168-Gb/s signal pulses were injected into the
1041–1135/01$10.00 © 2001 IEEE

1092 IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 13, NO. 10, OCTOBER 2001
Fig. 1. Experimental setup. MLFL: Mode-locked fiber laser. MOD:
Modulator. PPG: Pulse pattern generator. C: Calcite. BS: Babinet–Soleil phase
shifter. PL: Polarizer.
DISC together with unmodulated 1547-nm CW light generated
by an external-cavity semiconductor laser. The injection current
for the SOAwassetto 250 mA. Theaveragepowersofthesignal
pulses and of the CW light at the input of the SOA module were
10 and 16 dBm, respectively. The signal pulse energy coupled to
the SOA was estimated to be 240 fJ. The signal pulse duration at
the input of theDISC was 1.8 ps. The time delay provided by the
birefringence of the calcite was set to 2.0 ps, which determined
the duration of the output pulse. Thus, the pulse duration was
kept almost unchanged before and after wavelength conversion.
Also note that logic was not inverted in this wavelength conver-
sion. The 168-Gb/s output of the DISC was demultiplexed to
10.5 Gb/s by the HI-SMZ switch [7] to measure eye diagrams
and bit error rates (BERs).
III. R
ESULTS AND DISCUSSION
Fig. 2(a) shows the 168-Gb/s output waveform of the DISC
measured by a streak camera. The trace was recorded as the ac-
cumulation of many PRBS pulses, and thus was observed as
a regular pulse sequence. The trace indicates good uniformity
for all 16 multiplexed channels. From a trace measured with a
higher time resolution (
1.3 ps), shown in the inset of Fig. 2(a),
the extinction ratio was estimated to be more than 10 dB. An
output pulse duration of 1.9 ps was confirmed by the autocorre-
lation measurement as shown in Fig. 2(b).
Fig. 3 is the eye diagram for the 168-Gb/s output of the
DISC measured after DEMUX. A clear eye opening has been
achieved. Fig. 4(a) is the result of BER measurement, showing
error-free 168-Gb/s wavelength conversion. All 16 multiplexed
channels showed similar BER performance. For comparison,
a BER measurement result for error-free 84-Gb/s operation
is also shown in Fig. 4(b). (In 84-Gb/s operation, a pattern
length of 2
was used to drive the 10.5-Gb/s modulator
Fig. 2. (a) Streak camera trace for DISC output. Inset is a trace measured at a
higher timeresolution. (b) Auto-correlater trace for DISC output. The full-width
at half-maximum of the trace is 2.9 ps, indicating a duration of 1.9 ps when the
sech
pulse shape is assumed.
Fig. 3. Eye diagram for DISC output after DEMUX.
Fig. 4. (a) BER measurement results for 168 Gb/s.
10.5-Gb/s baseline.
MUX
+
DEMUX at 168 Gb/s.
MUX
+
wavelength conversion
+
DEMUX
at 168 Gb/s. (b) BER measurement results for 84 Gb/s.
10.5-Gb/s baseline.
MUX
+
wavelength conversion
+
DEMUX at 84 Gb/s.
before MUX.) The received power was measured for 10.5-Gb/s
signals fed into the preamplifier erbium doped fiber amplifier
(EDFA) of the detection system. The power penalty measured
from the 10.5-Gb/s baseline includes the effects of MUX
and DEMUX. For 84-Gb/s operation, the power penalty for

NAKAMURA et al.: 168-Gb/s ALL-OPTICAL WAVELENGTH CONVERSION WITH SMZ-TYPE SWITCH 1093
MUX and DEMUX was estimated to be about 2.5 dB from a
separate experiment [7]. Thus, the power penalty attributed to
84-Gb/s wavelength conversion was as low as 2 dB at a BER of
. The power penalty for 168-Gb/s wavelength conversion
increased to about 6 dB. These power penalties for wavelength
conversion are mainly due to a residual pattern effect induced
in the SOA by the data-modulated signal pulses. Because of the
pattern effect, we did not reach error-free operation with longer
PRBS lengths. The mechanism of suppressing the pattern effect
by using the relatively high average power of the CW light
is interpreted by the effective reduction in the carrier lifetime
of the SOA [4], [12]. For higher repetition, effective carrier
lifetime should be decreased by increasing the power of the
CW light. However, the intense CW light consumes the gain of
the SOA, and thus reduces the refractive index change induced
by the signal pulses. Thus, minimizing the pattern effect and
maximizing the refractive index change should be balanced at
a high repetition rate. We believe that this tradeoff is overcome
by developing SOAs in which higher current injection is
enabled. Although the observed performance depended on the
polarization of the input signal pulses at present, the operation
can be optimized to be polarization-independent in principle.
IV. C
ONCLUSION
We have achieved error-free all-optical wavelength con-
version at 168 Gb/s, which is the highest repetition rate ever
reported, with the Delayed Interference Signal-wavelength
Converter. Low-power-penalty 84-Gb/s operation has also
been achieved. We believe that the present operation is more
complete than earlier 100-Gb/s-level experiments because the
pulse duration is kept nearly unchanged, logic is noninverted,
and high extinction ratio output is obtained. The results confirm
that the Symmetric-Mach–Zehnder-type all-optical switches
can be driven by data-modulated 160-Gb/s signal pulses and
are applicable to various optical signal processing in future
OTDM systems.
R
EFERENCES
[1] K. Tajima, “All-optical switch with switch-off time unrestricted by
carrier lifetime,” Jpn. J. Appl. Phys., pt. 2, vol. 32, no. 12A, pp.
L1746–L1749, Dec. 1993.
[2] K. Tajima, S. Nakamura, and Y. Sugimoto, “Ultrafast polarization-dis-
criminating Mach–Zehnder all-optical switch,” Appl. Phys. Lett., vol.
67, no. 25, pp. 3709–3711, June 1995.
[3] Y. Ueno, S. Nakamura, K. Tajima, and S. Kitamura, “3.8-THz
wavelength conversion of picosecond pulse using a semiconductor
delayed-interference signal wavelength converter (DISC),” IEEE
Photon. Technol. Lett., vol. 10, pp. 346–348, Oct. 1998.
[4] Y. Ueno, S. Nakamura, and K. Tajima, “Ultrafast 168-GHz 1.5-ps 1-fJ
symmetric-Mach–Zehnder-type all-optical semiconductor switch,” Jpn.
J. Appl. Phys., pt. 2, vol. 39, no. 8A, pp. L806–L808, Aug. 2000.
[5] Y. Ueno, S. Nakamura, H. Hatakeyama, T. Tamanuki, T. Sasaki, and K.
Tajima, “168-Gb/s OTDM wavelength conversion using an SMZ-type
all-optical switch,” in Proc. 26th Eur. Conf. Optical Communication
2000, vol. 1, Munich, Germany, Sept., pp. 13–14.
[6] S. Nakamura, Y. Ueno, and K. Tajima, “Ultrafast (200-fs switching,
1.5-Tb/s demultiplexing) and high-repetition (10 GHz) operations of
a polarization-discriminating symmetric Mach–Zehnder all-optical
switch,” IEEE Photon. Technol. Lett., vol. 10, pp. 1575–1577, Nov.
1998.
[7] S. Nakamura, Y. Ueno, K. Tajima, J. Sasaki, T. Sugimoto, T. Kato, T.
Shimoda, M. Itoh,H. Hatakeyama, T. Tamanuki, andT. Sasaki, “Demul-
tiplexing of 168-Gb/s data pulses with a hybrid-integrated symmetric
Mach–Zehnder all-optical switch,” IEEE Photon. Technol. Lett., vol. 12,
pp. 425–427, Apr. 2000.
[8] S. Fischer, M. Dülk, E. Gamper, W. Vogt, E. Gini, H. Melchior, W. Hun-
ziker, D. Nesset, and A. D. Ellis, “Optical 3R regenerator for 40-Gb/s
networks,” Electron. Lett., vol. 35, no. 23, pp. 2047–2049, Nov. 1999.
[9] B. Mikkelsen, K. S. Jepsen, M. Vaa, H. N. Poulsen, K. E. Stubkjaer,
R. Hess, M. Duelk, W. Vogt, E. Gamper, E. Gini, P. A. Besse, H. Mel-
cior, S. Bouchoule, and F. Devaux, “All-optical wavelength converter
scheme for high-speed RZ signal formats,” Electron. Lett., vol. 33, pp.
2138–2139, Dec. 1997.
[10] J. Leuthold, C. H. Joyner, B. Mikkelsen, G. Raybon, J. L. Pleumeekers,
B. I. Miller, K. Dreyer, and C. A. Burrus, “100-Gb/s all-optical wave-
length conversion with integrated SOA delayed-interference configura-
tion,” Electron. Lett., vol. 36, pp. 1129–1130, June 2000.
[11] A. E. Kelly, I. D. Phillips, R. J. Manning, A. D. Ellis, D. Nesset, D. G.
Moodie, and R. Kashyap, “80-Gb/s all-optical regenerative wavelength
conversionusing semiconductor optical amplifier based interferometer,”
Electron. Lett., vol. 35, pp. 1477–1478, Aug. 1999.
[12] R. J. Manning, A. D. Ellis, A. J. Poustie, and K. J. Blow, “Semiconductor
laser amplifiers for ultrafast all-optical signal processing,” J. Opt. Soc.
Amer. B, Opt. Phys., vol. 14, pp. 3204–3216, Nov. 1997.
Citations
More filters

Journal ArticleDOI
26 Mar 2007
Abstract: We demonstrate error-free wavelength conversion at 320 Gb/s by employing a semiconductor optical amplifier that fully recovers in 56 ps. Error-free operation is achieved without using forward error correction technology. We employ optical filtering to select the blue sideband of the spectrum of the probe light, to utilize fast chirp dynamics introduced by the amplifier, and to overcome the slow gain recovery. This leads to an effective recovery time of less than 1.8 ps for the wavelength converter. The wavelength converter has a simple configuration and is implemented by using fiber-pigtailed components. The concept allows photonic integration

225 citations


Cites background from "168-Gb/s all-optical wavelength con..."

  • ...It has been demonstrated in [9] that a wavelength converter based on a delay-interferometric configuration can achieve 168 Gb/s, and this approach also allows photonic inte-...

    [...]


Journal ArticleDOI
Abstract: Error-free and pattern-independent wavelength conversion at 160 Gb/s is demonstrated. The wavelength converter utilizes a semiconductor optical amplifier (SOA) with a recovery time greater than 90 ps and an optical bandpass filter (OBF) placed at the amplifier output. This paper shows that an OBF with a central wavelength that is blue shifted compared to the central wavelength of the converted signal shortens the recovery time of the wavelength converter to 3 ps. The wavelength converter is constructed by using commercially available fiber-pigtailed components. It has a simple configuration and allows photonic integration.

212 citations


Journal ArticleDOI
Abstract: This paper presents views on the future of optical networking. A historical look at the emergence of optical networking is first taken, followed by a discussion on the drivers pushing for a new and pervasive network, which is based on photonics and can satisfy the needs of a broadening base of residential, business, and scientific users. Regional plans and targets for optical networking are reviewed to understand which current approaches are judged important. Today, two thrusts are driving separate optical network infrastructure models, namely 1) the need by nations to provide a ubiquitous network infrastructure to support all the future services and telecommunication needs of residential and business users and 2) increasing demands by the scientific community for networks to support their requirements with respect to large-scale data transport and processing. This paper discusses these network models together with the key enabling technologies currently being considered for future implementation, including optical circuit, burst and packet switching, and optical code-division multiplexing. Critical subsystem functionalities are also reviewed. The discussion considers how these separate models might eventually merge to form a global optical network infrastructure

188 citations


Cites methods from "168-Gb/s all-optical wavelength con..."

  • ...To maximize speed, push–pull configurations have been suggested where, by applying phase changes in both arms, performance can be significantly enhanced, with up to 160-Gb/s operation reported [ 42 ]....

    [...]


Journal ArticleDOI
Abstract: Ultrahigh nonlinear tapered fiber and planar rib Chalcogenide waveguides have been developed to enable highspeed all-optical signal processing in compact, low-loss optical devices through the use of four-wave mixing (FWM) and cross-phase modulation (XPM) via the ultra fast Kerr effect. Tapering a commercial As2Se3 fiber is shown to reduce its effective core area and enhance the Kerr nonlinearity thereby enabling XPM wavelength conversion of a 40 Gb/s signal in a shorter 16-cm length device that allows a broader wavelength tuning range due to its smaller net chromatic dispersion. Progress toward photonic chip-scale devices is shown by fabricating As2S3 planar rib waveguides exhibiting nonlinearity up to 2080 W-1ldr km-1 and losses as low as 0.05 dB/cm. The material's high refractive index, ensuring more robust confinement of the optical mode, permits a more compact serpentine-shaped rib waveguide of 22.5 cm length on a 7-cm- size chip, which is successfully applied to broadband wavelength conversion of 40-80 Gb/s signals by XPM. A shorter 5-cm length planar waveguide proves most effective for all-optical time-division demultiplexing of a 160 Gb/s signal by FWM and analysis shows its length is near optimum for maximizing FWM in consideration of its dispersion and loss.

139 citations


Cites background from "168-Gb/s all-optical wavelength con..."

  • ...Nonlinear signal processing has previously been performed in various media such as optical fiber [2]–[6], [8], [9], [12], [13], [17], [20], [22], [25], semiconductor optical amplifiers (SOA) [11], [14], [24], and periodically poled LiNbO3 (PPLN) [7]....

    [...]


Journal ArticleDOI
Abstract: 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

124 citations


Additional excerpts

  • ..., [11]–[14]), modulation-format convert-...

    [...]


References
More filters

Journal ArticleDOI
Abstract: We propose a symmetric Mach-Zehnder-type all-optical switch which is based on the nonlinear refractive index change induced in semiconductors. Unlike most all-optical switches, the switch-off time, as well as the switch-on time, of this novel device is not limited by the usually slow carrier lifetime, allowing a very fast switching speed. Its switching characteristics are theoretically examined under various conditions. It is shown that the device offers a nearly square modulation characteristic that is suitable for most switching applications.

206 citations


"168-Gb/s all-optical wavelength con..." refers background in this paper

  • ...In achieving such ultrafast optical signal processing, the Symmetric-Mach–Zehnder (SMZ) all-optical switch family, including the original SMZ switch [1], the Polarization-Discriminating SMZ (PD-SMZ) switch [2], and the Delayed-Interference Signal-wavelength Converter (DISC) [3]–[5] is quite promising....

    [...]


Journal ArticleDOI
Abstract: Recent progress in the use of semiconductor laser amplifiers (SLA's) for high-speed all-optical switching is reviewed. We show that, despite SLA's having lifetimes of ⩾100 ps, they are, to date, the most promising material system for all-optical ultrafast signal processing. We highlight the role of SLA carrier dynamics, which permits switching rates faster than the recovery time. Experimental results are presented that imply that switching rates of as much as ∼100 GHz should be possible. Recent experiments are described in which SLA-based switches were incorporated into novel all-optical architectures.

184 citations


"168-Gb/s all-optical wavelength con..." refers background in this paper

  • ...In such operation, the pattern effect due to high repetition data-modulated signal pulses is suppressed by injecting unmodulated continuous-wave (CW) light or clock pulses into SOAs at relatively high average power [4], [12]....

    [...]


09 Jul 2000
Abstract: First all-optical 100 Gbit/s wavelength conversion employing cross-phase modulation is demonstrated with a recently introduced completely integrated and packaged delayed-interference configuration.

172 citations


"168-Gb/s all-optical wavelength con..." refers background or methods in this paper

  • ...experiments [10] exhibiting ultrafast all-optical wavelength conversion accompanied the conversion from return-to-zero (RZ) to nonreturn-to-zero (NRZ) and/or logic inversion....

    [...]

  • ...To date, 100-Gb/s wavelength conversion [10] and 80-Gb/s pulse regeneration [11] have been shown by using the push–pull switching mechanism of the SMZ all-optical switch incorporating semiconductor optical amplifiers (SOAs)....

    [...]


Journal ArticleDOI
Abstract: The authors report all-optical 100 Gbit/s wavelength conversion employing cross-phase modulation for the first time

156 citations


Journal ArticleDOI
Abstract: A new all-optical semiconductor-band-filling-based wavelength converter, named delayed-interference signal-wavelength converter (DISC), is proposed. Its speed is not restricted by the carrier lifetime and its structure is very simple: it consists of only two essential components, namely, a semiconductor optical amplifier and a passive split-delay. Using this converter, 3.8-THz-shifted (from 1530 to 1560-nm) 14-ps-long pulses are generated from 1530-nm 140-fJ 0.7-ps pulses with high-conversion efficiency.

134 citations


"168-Gb/s all-optical wavelength con..." refers background in this paper

  • ...The DISC consists of a nonlinear waveguide and a delay line, as detailed in [3]....

    [...]

  • ...(a) Streak camera trace for DISC output....

    [...]

  • ...In achieving such ultrafast optical signal processing, the Symmetric-Mach–Zehnder (SMZ) all-optical switch family, including the original SMZ switch [1], the Polarization-Discriminating SMZ (PD-SMZ) switch [2], and the Delayed-Interference Signal-wavelength Converter (DISC) [3]–[5] is quite promising....

    [...]

  • ...3 is the eye diagram for the 168-Gb/s output of the DISC measured after DEMUX....

    [...]

  • ...The 168-Gb/s output of the DISC was demultiplexed to 10.5 Gb/s by the HI-SMZ switch [7] to measure eye diagrams and bit error rates (BERs). lation measurement as shown in Fig....

    [...]


Frequently Asked Questions (1)
Q1. What are the contributions in "168-gb/s all-optical wavelength conversion with a symmetric-mach–zehnder-type switch" ?

Error-free all-optical wavelength conversion at 168 Gb/s, which is the highest repetition rate ever reported, has been achieved by using a Symmetric-Mach–Zehnder ( SMZ ) -type switch.