Fig 5 - uploaded by Kenneth Kin-Yip Wong
Content may be subject to copyright.
Source publication
With the presence of multiple-WDM input signals, ON-OFF keying (OOK)-modulated signals suffer from crosstalk in fiber optical parametric amplifier (OPA) due to cross-gain modulation (XGM) and four-wave mixing (FWM) effects. We demonstrated substantial crosstalk suppression in one-pump OPA by using return-zero differential phase-shift keying (RZ-DPS...
Contexts in source publication
Context 1
... servable for OOK-modulated signals (Fig. 4(c) In order to investigate the FWM-induced crosstalk level, the FWM-tone powers were measured with one signal channel switched OFF in each measurement. Table I shows the crosstalk level relative to the original signal power, and the spectra of out- put signals with channel #3 switched OFF are shown in Fig. 5. As shown from the figure, the crosstalk levels for OOK signals are, in general, higher than their DPSK counterparts. Moreover, FWM-induced crosstalk experienced by NRZ signals is more severe than their RZ counterparts. This result can be explained by the pulse walkoff effect between channels. As the signals are placed at wavelengths ...
Context 2
... of bit period (RZ), the portion that signal pulses in different chan- nels overlap decreases given the same amount of walkoff in the decorrelation fiber. As a result, the FWM efficiencies be- tween channels also decreases [24]. This means choosing the RZ-DPSK format can also suppress FWM-induced crosstalk ef- fectively. In addition, as seen in Fig. 5, there are two distinct FWM tones at 1570.9 nm and 1571.1 nm in the OOK spectra, while only one FWM tone at 1571.1 nm is observable in the NRZ-DPSK spectrum. The tone at 1571.1 nm, which is inher- ited from the pump-signal FWM, does not collide with chan- nels. However, the tone at 1570.9 nm, which was generated by signal-signal FWM, ...
Similar publications
In this paper we present results from the study of optical signal amplification using Raman assisted fiber optical parametric amplifier with considerable benefits for S-band telecommunication systems where the use of widely used erbium-doped fiber amplifier is limited. We have created detailed models and performed computer simulations of combined R...
We demonstrate a scheme for correcting the angular dispersion of the 3.1-m idler beam from a high-repetitionrate, KTiOAsO4 (KTA) based noncollinear optical parametric amplifier pumped at 1.03 m and seeded by broadband signal pulses at 1.55 m. Following angular dispersion correction, successful temporal chirp compensation was possible and a close to...
We report a fiber optical parametric amplifier (FOPA) based on a photonic crystal fiber (PCF) with optimized dispersion and nonlinear properties pumped by a mode-locked ytterbium-doped fiber laser. Wavelength-tunable parametric gain bands can be obtained by adjusting the pump wavelength from the anomalous to the normal dispersion regime. By utilizi...
Phase-sensitive amplification is of great research interest owing to its potential in noiseless amplification. One key feature in a phase-sensitive amplifier is the gain extinction ratio defined as the ratio of the maximum to the minimum gains. It quantifies the capability of the amplifier in performing low-noise amplification for high phase-sensit...
We proposed a hybrid fiber Raman/parametric amplifier which can have significant gain enhancement over that of a Raman-assisted fiber optical parametric amplifier using the same length of fiber, Raman and parametric pump powers.
Citations
... 14 FOPAs have attracted significant attention in the recent past for DWDM systems due to their capabilities to provide high gain bandwidth and low noise figure (NF). [15][16][17] Jazayerifar et al. 17 have derived the analytical expressions for the FOPA-based DWDM system and confirmed the feasibility of FOPAs as in-line amplifiers for broadband longhaul DWDM systems. ...
A hybrid optical amplifier is proposed using a combination of Er-Yb codoped waveguide amplifier (EYDWA) and fiber optical parametric amplifier (FOPA). The scheme is investigated for 100 × 40 Gb / s dense wavelength division multiplexed (DWDM) system at 0.2-nm channel spacing. The parameters are optimized to achieve a flat gain of >30.6 dB, with a gain ripple of 2.67 dB. This is obtained over a wavelength range of 1542 to 1562 nm at -10-dBm optimum input power per channel, without using any costly gain flattening scheme. For higher input powers up to 10 dBm, an increase in gain ripple from 2.67 to 6.13 dB is observed. The gain ripple of 2.67 dB of the proposed EYDWA-dual pump FOPA configuration is also much better than 10.32 dB for the hybrid EYDWA-single pump FOPA. The obtained high and flat gain, along with the low noise figure, confirms the usefulness of the proposed amplifier for applications in long-haul DWDM systems. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
... Both high powered IM pump signals (A & B) modulate the gain spectrum of the optical parametric medium consisting of the HNLF. The cross-gain modulation (XGM) process occurs between two injected IM pump/data signals (A & B) resulting in intensity fluctuations, depending upon which data signal travels with depleted/un-depleted part of OPA gain spectrum Lai et al. 2008b;Marhic 2008;Lai et al. 2008a;Sakamoto et al. 2002;Kuo et al. 2008;Wong et al. 2006;Wong et al. 2007a, b;Guo and Shu 2014;Marhic et al. 2001). So, due to occurrence of parametric pump depletion effect (cross-gain modulation (XGM)), the signals centred at @k A and @k B take the shape of respective A: ...
... B & A:B logic functions, which are further utilized for the representation of borrow outputs of the proposed cascadable half-subtraction module Lai et al. 2008b;Marhic 2008;Lai et al. 2008a;Sakamoto et al. 2002;Kuo et al. 2008;Wong et al. 2006;Wong et al. 2007a;Wong et al. 2007b;Guo and Shu 2014;Marhic et al. 2001). Two bandpass filters (BPF) as depicted in Fig. 1 centred at @k A and @k B wavelengths, are utilized to extract XGM depleted borrow signals A: ...
An all-optical half-subtracter is proposed based on harnessing of 3rd order (χ⁽³⁾) non-linear effects such as cross-gain modulation (XGM) and cross-phase modulation (XPM) inside a single highly non-linear finer (HNLF), which is capable of operating at 100 Gbps operating bit rate. The XGM effect occurrence in HNLF has been exploited for the implementation of both borrow logics (A.B¯&A¯.B). Whereas, the difference output of proposed half-subtracter represented by A⊕ B logic is obtained from XPM process taking place on low-energy continuous-wave (CW) probe signal which is co-propagating with two high energy pump signals. The proposed half-subtracter can exhibit cascadability, owing to single wavelength centric nature of all the three logic functions generated such as A. B¯ , A¯.B&A⊕B. The proposed half-subtracter functionality is verified through inspection of temporal waveforms and eye diagrams of achieved output logic functions. Further, dependence of output function’s Q-factor and Extinction Ratio (dB) values on following parameters: pump/data signal powers (PA& PB), CW probe power (PCW) and choice of CW probe operating wavelength (λCW) is also investigated and discussed. In the final stages, an investigation has been carried out by implementing secondary logic functions ((A.B¯).C¯,(A.B¯¯).C,(A¯.B).C¯,(A¯.B¯).C,(A⊕B¯).C&(A⊕B).C¯) to examine the cascade-ability characteristics of the proposed half-subtracter. It has been shown by calculating temporal waveforms and eye diagrams of secondary logic functions such as (A.B¯).C¯,(A.B¯¯).C,(A¯.B).C¯,(A¯.B¯).C,(A⊕B¯).C&(A⊕B).C¯ that proposed cross-modulation effects in HNLF based half-subtracter is indeed cascadable.
... Fiber optical parametric amplifiers (FOPAs) are promising amplifiers for Wavelength Division Multiplexed (WDM) systems [1,2] due to their capabilities to provide high gain and low-noise, broadband amplification [1,3]. The first demonstration of optical parametric amplification was reported by Stolen in low-loss optical fibers [4]. ...
We demonstrate improved performance of parametric amplifier cascaded with Raman amplifier for gain of 54.79 dB. We report amplification of L-band using 100 × 10 Gbps Dense Wavelength Division Multiplexed (DWDM) system with 25 GHz channel spacing. The gain achieved is the highest reported so far with gain flatness of 3.38 dB without using any gain flattening technique. Hybrid modulated parametric pump is used for suppressing four-wave mixing (FWM) around pump region, resulting in improvement of gain flatness by 2.42 dB. The peak to peak variation of gain is achieved less than 1.6 dB. DWDM system with 16-channel, 25 GHz spaced system has been analyzed thoroughly with hybrid modulated parametric pump amplified Raman-FOPA amplifier for gain flatness and improved performance in terms of BER and
Q
-factor.
... One attractive feature based on wavelengthdivision multiplexing (WDM) is multicasting, which transmits data with simultaneous wavelength conversions and provides WDM network functionality [2]- [4]. Furthermore, a return-to-zero (RZ) modulation format is more robust to nonlinear impairments and crosstalk compared with a non-RZ (NRZ) encoding [5], [6]. We consider the multicasting scheme as shown in Fig. 1 with the interconnections among nodes that uses the concept of a light tree or light path in a wavelength-routed network, which is connected from one source node to several destination nodes [7]. ...
All-optical 1-to-6 wavelength multicasting of a 10-Gb/s picosecond-tunable-width converted return-to-zero (RZ)-on-off-keying (OOK) data signal using a wideband-parametric pulse source from a distributed Raman amplifier (DRA) is experimentally demonstrated. Width-tunable wavelength multicasting within the C-band with approximately 40.6-nm of separation with various compressed RZ data signal inputs have been proposed and demonstrated. The converted multicast pulse widths can be flexibly controlled down to 2.67 ps by tuning the Raman pump powers of the DRA. Nearly equal pulse widths at all multicast wavelengths are obtained. Furthermore, wide open eye patterns and penalties less than 1.2 dB at the 10-9 bit-error-rate (BER) level are found.
... This is because the front edge of the pulse will saturate the amplifier, so the amplifier requires time to recover the gain before the trailing edge arrives, and it is called gain recovery time [25]. When gain saturation occurs in SOA, the light intensity of other channels impact the gain of neighboring channels, which causes cross gain crosstalk, resulting from cross gain modulation [31]. This dependence of SOAs on the bit pattern is considered quite problematic for WDM systems. ...
Currently, the WDM technique is adopted by many telecommunication operators to increase the transmission capacity through employing more wavelengths on the same fiber. Optical components used by WDM systems like multiplexer/de-multiplexer and OA are prone to crosstalk. According to the literature, one of the limitations in the WDM systems is interchannel crosstalk which results from the leakage of the de-multiplexed signals of different wavelengths with the desired signal. The use of SOAs in WDM systems instead of EDFAs might consider as a cost effective option. However, employing SOAs in WDM systems could introduce non-linear interchannel crosstalk due to the Cross Gain Modulation (XGM), which results from the gain seen by the all signals vary by the absence or the presence of other channels. The saturation behavior of an SOA in WDM systems is explained in this paper using steady state and simple Ordinary Differential Equations (ODE) models. The objective of this paper is to investigate the BER performance of WDM systems employing SOA by considering the interchannel and cross gain crosstalk effects. A modified Binomial Distribution (BD) method is proposed to include the effect of cross gain crosstalk through using the output of the steady state model. This BER model is applicable under the assumption of 〖〖 τ〗_p>>τ〗_c .
... One approach for reducing FWM crosstalk is to use short fibers and high pump powers [8], but pump quality could be an issue. Other approaches include using different modulation formats [9] and special wavelength assignment [10], but they cannot easily adapt to different systems. Recently we proposed to follow a fiber OPA by a different type of booster amplifier, such as an erbium-doped fiber amplifier (EDFA) or a Raman amplifier, in order to push the high-power fields outside the OPA and into a medium less prone to FWM [11,12]. ...
We demonstrate reduction of four-wave mixing crosstalk using hybrid optical parametric amplifier with erbium-doped fiber amplifier. Crosstalk reduction of more than 13 dB has been achieved while providing 20-dB gain. Noise figures of different amplifier configurations are compared. Bit error rate measurements confirm the hybrid configuration introduces < 0.5 dB and < 1.5 dB power penalties in signal and idler wavelength, respectively, compared with a pure optical parametric amplifier.
... However, the performance of fiber OPAs in WDM systems is limited by four-wave mixing (FWM) crosstalk [8][9][10][11][12][13][14]. To date, the highest transmission rate demonstrated for a fiber OPA (used as PIA) is about 1 Tb/s. ...
Following a fiber optical parametric amplifier, used as a wavelength converter or in the phase-sensitive mode, by a phase-insensitive amplifier (PIA) can significantly reduce four-wave mixing between signals in broadband systems. We derive the quantum mechanical noise figures (NF) for these two hybrid configurations, and show that adding the PIA only leads to a moderate increase in NF.
... Fig. 1 Illustration of the signal quality degradation of WDM system due to XGM and FWM effects in a 2P-OPA. [19]. ...
... We demonstrated substantial crosstalk suppression in onepump OPA by using RZ-DPSK modulation format, of which its pattern independent amplitude and sub-unity duty cycle would be effective in reducing XGM and FWM effects significantly. By using RZ-DPSK format with eight 10 Gb/s channel, 100 GHz channel spacing, Q-factor penalty of RZ-DPSK signal was reduced by 2.4 dB (on average) comparing to RZ-OOK counterparts as shown in Fig. 2 [19]. ...
... Experiments have confirmed that the signal at 1554 nm could be flexibly converted to the C-band (1532- Fig. 4 Bit patterns for the inputs and outputs of XOR-, OR-, and NOT-gates [21]. [19]. ...
Fiber optical parametric amplifiers (OPAs) are based on the third-order nonlinear susceptibility of glass fibers. If two strong pumps and a weak signal are fed into a fiber, an idler is generated. Signal and idler can grow together if pump power is high enough, and phase matching occurs. Until recently, impressive performance of fiber OPAs has been demonstrated in different respects. However, secondary effects should be addressed before OPAs can be utilized in practical applications. Here we report some of these effects, either exploiting them as in the parametric processor such as optical logic gates, inverted and non-inverted wavelength converter, and ultra-wideband monocycle and doublet pulses generator, or suppressing them as in the optical amplifier for WDM systems.
... . Q-factor penalty ofRZ-DPSK and RZ-OOK signals at different channel [12]. Fig. 2. Bit patterns for the inputs and outputs ofXOR-, OR-, and NOT-gates [13]. ...
... J557.2n m ~ ~-'r-I ~,..,., NOT l nllU1 Ira :Fig. 1. Q-factor penalty ofRZ-DPSK and RZ-OOK signals at different channel [12]. The author's research group has proposed different schemes to suppress such kind of crosstalk. ...
... The author's research group has proposed different schemes to suppress such kind of crosstalk. Namely, the twoorthogonal pumps OPA (20P-OPA) [10]; WDM signals with I2Qlarization-interieaving (POIN) [11]; and recently by return-to-zero differential phase-shift-keying (RZ-DPSK) modulation signal format which suppress the power penalty due to crosstalk, by comparing the eye-diagrams and bit-error-rate (BER) of different formats [12]. We demonstrated substantial crosstalk suppression in one-pump OPA by using RZ-DPSK modulation format, of which its pattern independent amplitude and sub-unity duty cycle would be effective in reducing XGM and FWM effects significantly. ...
Fiber optical parametric amplifiers (OPAs) are based on the third-order nonlinear susceptibility of glass fibers. If two strong pumps and a weak signal are fed into a fiber, an idler is generated. Signal and idler can grow together if pump power is high enough, and phase matching occurs. Until recently, impressive performance of fiber OPAs has been demonstrated in different respects. However, second-order effects should be addressed before OPAs can be utilized in practical applications. Here we report some of these effects, either exploiting them as in the parametric processor such as optical logic gates, inverted and non-inverted wavelength converter, and ultra-wideband monocycle and doublet pulses generator, or suppressing them as in the optical amplifier for WDM systems.
This work demonstrates optical amplification in the entire C- and L-bands. A hybrid amplifier consisting of one stage of Er-Yb co-doped fiber amplifier (EYDFA) and two stages of fiber optical parametric amplifier is proposed. The EYDFA and parametric amplifier parameters have been carefully selected to achieve gain over complementary bandwidth regions, resulting in better gain flatness over 110 nm bandwidth. The proposed amplifier is investigated for 12 × 100 Gb/s wavelength division multiplexed system at channel spacing of 10 nm. Results show a flat gain of >27.42 dB with gain ripple of 3.17 dB, obtained over a wavelength range of 1530 to 1640 nm.
