OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 27 — Dec. 19, 2011
  • pp: 26353–26358
« Show journal navigation

A robust and dither-free technique for controlling driver signal amplitude for stable and arbitrary optical phase modulation

Yanfu Yang, Chao Lu, Alan Pak Tao Lau, Yong Yao, Yunxu Sun, Jun Jun Xiao, H. Y. Tam, and P. K. A. Wai  »View Author Affiliations


Optics Express, Vol. 19, Issue 27, pp. 26353-26358 (2011)
http://dx.doi.org/10.1364/OE.19.026353


View Full Text Article

Acrobat PDF (1033 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

We propose a robust and dither-free technique using a delay line interferometer, a balanced detector and simple signal processing to adjust the amplitude of the driver signal of an optical phase modulator automatically for stabilizing the modulated phase of an optical carrier at any arbitrary value. The technique is analytically shown to be robust against practical device imperfections. A stable 45 degrees phase shift with deviation less than ± 0.8 degrees is experimentally demonstrated.

© 2011 OSA

1. Introduction

Advanced modulation formats have been one of the enabling technologies for high spectral efficiency (SE) and ultra-large-capacity long distance fiber communication systems [1

1. J. M. Kahn and K. P. Ho, “Spectral efðciency limits and modulation/detection techniques for DWDM systems,” IEEE J. Sel. Top. Quantum Electron. 10(2), 259–272 (2004). [CrossRef]

, 2

2. A. H. Gnauck and P. J. Winzer, “Optical phase-shift-keyed transmission,” J. Lightwave Technol. 23(1), 115–130 (2005). [CrossRef]

]. Quadrature-phase-shift-keying (QPSK) with polarization-division-multiplexing [3

3. C. R. Fludger, T. Duthel, D. van den Borne, C. Schulien, E. Schmidt, T. Wuth, E. de Man, G. D. Khoe, and H. de Waardt, 10 x 111 Gbit/s, 50 GHz Spaced, POLMUX-RZ-DQPSK Transmission over 2375 km Employing Coherent Equalisation,” in Optical Fiber Communication Conference and Exposition and The National Fiber Optic Engineers Conference, OSA Technical Digest Series (CD) (Optical Society of America, 2007), paper PDP22. http://www.opticsinfobase.org/abstract.cfm?URI=OFC-2007-PDP22

, 4

4. A. H. Gnauck, R. W. Tkach, A. R. Chraplyvy, and T. Li, “High-capacity optical transmission systems,” J. Lightwave Technol. 26(9), 1032–1045 (2008). [CrossRef]

] has been studied to obtain SE of 2.0 b/s/Hz in 100 Gb/s dense wavelength-division-multiplexing (DWDM) systems. To meet the requirement of growing bandwidth demand, higher-order phase-shift-keying (PSK) [5

5. X. Zhou, J. Yu, D. Qian, T. Wang, G. Zhang, and P. Magill, “High-Spectral-Efficiency 114-Gb/s Transmission using PolMux-RZ-8PSK modulation format and single-ended digital coherent detection technique,” J. Lightwave Technol. 27(3), 146–152 (2009). [CrossRef]

7

7. G.-W. Lu, T. Sakamoto, and T. Kawanishi, “Rectangular QPSK for generation of optical eight-ary phase-shift keying,” Opt. Express 19(19), 18479–18485 (2011). [CrossRef] [PubMed]

] and quadrature amplitude modulation (QAM) [8

8. X. Zhou, J. Yu, M. Huang, Y. Shao, T. Wang, P. Magill, M. Cvijetic, L. Nelson, M. Birk, G. Zhang, S. Y. Ten, H. B. Matthew, and S. K. Mishra, “32Tb/s (320x114Gb/s) PDM-RZ-8QAM Transmission over 580km of SMF-28 Ultra-Low-Loss Fiber,” in National Fiber Optic Engineers Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper PDPB4. http://www.opticsinfobase.org/abstract.cfm?URI=NFOEC-2009-PDPB4

10

10. X. Zhou, J. Yu, M. Huang, Y. Shao, T. Wang, L. Nelson, P. Magill, M. Birk, P. I. Borel, D. W. Peckham, R. Lingle, and B. Zhu, “64-Tb/s, 8 b/s/Hz, PDM-36QAM transmission over 320 km using both pre- and post-transmission digital signal processing,” J. Lightwave Technol. 29(4), 571–577 (2011). [CrossRef]

] are investigated to increase the SE further to achieve beyond 100 Gb/s capacity in each DWDM grid. In practical QPSK/PSK/QAM transmitters, the bias voltages and/or the driver signal amplitudes should always be stabilized at the specified operating points for generating optimal signal constellations. However, temperature fluctuation, device aging and amplifier heating will all lead to the drift of the above operating parameters and thus distort the signal constellations. Therefore, automatic control of these key parameters in these multi-level optical transmitters [5

5. X. Zhou, J. Yu, D. Qian, T. Wang, G. Zhang, and P. Magill, “High-Spectral-Efficiency 114-Gb/s Transmission using PolMux-RZ-8PSK modulation format and single-ended digital coherent detection technique,” J. Lightwave Technol. 27(3), 146–152 (2009). [CrossRef]

10

10. X. Zhou, J. Yu, M. Huang, Y. Shao, T. Wang, L. Nelson, P. Magill, M. Birk, P. I. Borel, D. W. Peckham, R. Lingle, and B. Zhu, “64-Tb/s, 8 b/s/Hz, PDM-36QAM transmission over 320 km using both pre- and post-transmission digital signal processing,” J. Lightwave Technol. 29(4), 571–577 (2011). [CrossRef]

] is essential for implementing future high SE systems. Up to now, the reported automatic control schemes focus on automatic bias control in dual-parallel Mach-Zehnder modulator (MZM) for QPSK signal generation [11

11. P. S. Cho, J. B. Khurgin, and I. Shpantzer, “Closed-loop bias control of optical quadrature modulator,” IEEE Photon. Technol. Lett. 18(21), 2209–2211 (2006). [CrossRef]

, 12

12. H. Kawakami, E. Yoshida, and Y. Miyamoto, “Asymmetric dithering technique for bias condition monitoring in optical QPSK modulator,” Electron. Lett. 46(6), 430–431 (2010). [CrossRef]

], arbitrary optical signal generation [13

13. T. Yoshida, T. Sugihara, K. Uto, H. Bessho, K. Sawada, K. Ishida, K. Shimizu, and T. Mizuochi, “A study on automatic bias control for arbitrary optical signal generation by dual-parallel Mach–Zehnder modulator,” in Proceeding of IEEE European Conference on Optical Communication (Torino, Italy, 2010), Paper Tu.3.A.6.

15

15. H. Choi, Y. Takushima, H. Y. Choi, J. H. Chang, and Y. C. Chung, “Modulation-Format-Free Bias Control Technique for MZ Modulator Based on Differential Phasor Monitor,” in Optical Fiber Communication Conference, OSA Technical Digest (CD) (Optical Society of America, 2011), paper JWA033. http://www.opticsinfobase.org/abstract.cfm?URI=OFC-2011-JWA033

] and orthogonal frequency division multiplexing (OFDM) signal generation [16

16. W. R. Peng, B. Zhang, X. X. Wu, K. M. Feng, A. E. Willner, and S. Chi, “Compensation for I/Q imbalances and bias deviation of the Mach-Zehnder modulators in direct-detected optical OFDM systems,” IEEE Photon. Technol. Lett. 21(2), 103–105 (2009). [CrossRef]

, 17

17. P. S. Cho and M. Nazarathy, “Bias control for optical OFDM transmitters,” IEEE Photon. Technol. Lett. 22(14), 1030–1032 (2010). [CrossRef]

]. In these schemes, different feed-back signals are monitored, including optical output power [11

11. P. S. Cho, J. B. Khurgin, and I. Shpantzer, “Closed-loop bias control of optical quadrature modulator,” IEEE Photon. Technol. Lett. 18(21), 2209–2211 (2006). [CrossRef]

14

14. M. Sotoodeh, Y. Beaulieu, J. Harley, and D. L. McGhan, “Modulator bias and optical power control of optical complex e-field modulators,” J. Lightwave Technol. 29(15), 2235–2248 (2011). [CrossRef]

] or its statistics [17

17. P. S. Cho and M. Nazarathy, “Bias control for optical OFDM transmitters,” IEEE Photon. Technol. Lett. 22(14), 1030–1032 (2010). [CrossRef]

], RF power spectrum [11

11. P. S. Cho, J. B. Khurgin, and I. Shpantzer, “Closed-loop bias control of optical quadrature modulator,” IEEE Photon. Technol. Lett. 18(21), 2209–2211 (2006). [CrossRef]

] and differential phasor [15

15. H. Choi, Y. Takushima, H. Y. Choi, J. H. Chang, and Y. C. Chung, “Modulation-Format-Free Bias Control Technique for MZ Modulator Based on Differential Phasor Monitor,” in Optical Fiber Communication Conference, OSA Technical Digest (CD) (Optical Society of America, 2011), paper JWA033. http://www.opticsinfobase.org/abstract.cfm?URI=OFC-2011-JWA033

]. Meanwhile, automatic control of the driver signal amplitude of the phase modulator (PM) are also essential to ensure the long-term stability of the transmitter in the implementation of multi-level PSK systems [5

5. X. Zhou, J. Yu, D. Qian, T. Wang, G. Zhang, and P. Magill, “High-Spectral-Efficiency 114-Gb/s Transmission using PolMux-RZ-8PSK modulation format and single-ended digital coherent detection technique,” J. Lightwave Technol. 27(3), 146–152 (2009). [CrossRef]

, 18

18. K. Fukuchi, “Proposal and Feasibility Study of a 6-Level PSK Modulation Format Based System for 100-Gb/s Migration,” in Optical Fiber Communication Conference and Exposition and The National Fiber Optic Engineers Conference, OSA Technical Digest (CD) (Optical Society of America, 2008), paper OMI6. http://www.opticsinfobase.org/abstract.cfm?URI=OFC-2008-OMI6

] or QAM system [8

8. X. Zhou, J. Yu, M. Huang, Y. Shao, T. Wang, P. Magill, M. Cvijetic, L. Nelson, M. Birk, G. Zhang, S. Y. Ten, H. B. Matthew, and S. K. Mishra, “32Tb/s (320x114Gb/s) PDM-RZ-8QAM Transmission over 580km of SMF-28 Ultra-Low-Loss Fiber,” in National Fiber Optic Engineers Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper PDPB4. http://www.opticsinfobase.org/abstract.cfm?URI=NFOEC-2009-PDPB4

]. To the best of our knowledge, however no automatic control technique has ever been proposed to date to achieve stable and arbitrary optical phase modulation.

In this paper, we propose and demonstrate a dither-free control technique for controlling the driver signal amplitude of a phase modulator. Using a delay line interferometer (DLI), a balanced photo-detector (BPD) and simple signal processing, the resultant phase shift from a phase modulator can be stabilized at an arbitrary value using dither-free feedback. The proposed technique is analytically shown to be insensitive to devices imperfections from the DLI and the BPD. This can reduce the implementation cost as a result of lower requirements for devices qualities. Furthermore, this control scheme is dither-free and hence the phase distortion induced by a dither signal is avoided. This advantage is especially beneficial for the multi-level modulator implementations because the modulated signal will be more sensitive to phase errors for higher-order modulation formats. In particular, a stable phase shift of 45 degrees is experimentally demonstrated and may help pave the way for practical and stable setups for 8PSK/8QAM transmitter realizations [5

5. X. Zhou, J. Yu, D. Qian, T. Wang, G. Zhang, and P. Magill, “High-Spectral-Efficiency 114-Gb/s Transmission using PolMux-RZ-8PSK modulation format and single-ended digital coherent detection technique,” J. Lightwave Technol. 27(3), 146–152 (2009). [CrossRef]

, 8

8. X. Zhou, J. Yu, M. Huang, Y. Shao, T. Wang, P. Magill, M. Cvijetic, L. Nelson, M. Birk, G. Zhang, S. Y. Ten, H. B. Matthew, and S. K. Mishra, “32Tb/s (320x114Gb/s) PDM-RZ-8QAM Transmission over 580km of SMF-28 Ultra-Low-Loss Fiber,” in National Fiber Optic Engineers Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper PDPB4. http://www.opticsinfobase.org/abstract.cfm?URI=NFOEC-2009-PDPB4

].

2. Operating principle

Figure 1
Fig. 1 Block diagram of the proposed control technique for a phase modulator. DFB- Distributed Feedback Laser; PM- Phase Modulator; MZM- Mach-Zehnder Modulator; PPG- Pulse Pattern Generator; BPD- Balanced Photo-Detector; DLI- Delay Line Interferometer; AMP- Amplifier.
shows the block diagram of the proposed technique for controlling the driver signal amplitude of a phase modulator. The control module is shown in the gray box. A typical multi-level transmitter consists of a PM cascaded with a subsequent MZM-based modulator. A portion of the output light from the PM is tapped and sent to a DLI. The DLI has a delay of symbol period T and a phase offset φ tuned by an external applied voltage Vp. A balanced photo-detector then converts the optical signal from the DLI into an electrical signal, which is then sampled asynchronously with a low-speed sampler. The samples are then collected to construct a histogram. In this scheme, φ is switched between 0 and 90 degrees alternatively. In the histograms, the peak locations for φ = 0 and φ = 90 degrees are calculated and sent to the control module as the input parameters. With these input parameters monitored, the control module adjusts the output parameter of the gain voltage Vg of the driver amplifier automatically, which in turn adjusts the driver signal amplitude Vpp so that the generated phase shift of the PM is stabilized at a specified value.

To analytically illustrate the operating principle of the proposed technique, let E(t) be the optical field after the PM with constant power P. The two couplers included in the DLI have their respective splitting ratios of α1:(11) and α2:(12), and the responsivities of the upper and lower photo-detector (PD) in the BPD are 1 and β respectively. In this case, the output signal I of the BPD is given by:

I={α1(1α2)+α2(1α1)β[α1α2+(1α1)(1α2)]}P+2α1α2(1α2)(1α1)(1+β)Re{E(tT)E*(t)eiφ}=C1P+C2Re{E(tT)E*(t)eiφ}.
(1)

In the above expression, C1 and C2 are two constants determined by α1, α2 and β only. The first term C1P is a DC component and will become zero when one of the two splitting ratios is ideal (0.5:0.5) and the responsivities of the two photo-detectors are identical. Assuming that the phase shift generated by the PM is θ, the phase difference between the two consecutive symbols after the PM will be one of the three possible values of -θ, 0 or θ. Therefore, E(t-T)E*(t) can be Pe-iθ, P, or Pe and the BPD output signal I in Eq. (1) has three possible values:

μ1=C1P+C2Pcos(θ+φ),μ2=C1P+C2Pcos(φ)orμ3=C1P+C2Pcos(θφ).
(2)

In this scheme, the phase offset φ should be switched between 0 and 90 degrees. Since the phase offset φ drifts because of temperature fluctuations in practice, Vp should be controlled adaptively to stabilize φ at zero or 90 degrees. With μ2 monitored as the error signal, the phase offset φ can be stabilized at 0 degree by maximizing μ2=C1P+C2Pcos(φ). For the case of φ=90 degrees, one can monitor 13)/2-μ2 = C2Pcosφ∙(cosθ-1) as the error signal. By tuning Vp so that the error signal approaches zero, φ can be stabilized at 90 degrees.

In Eq. (2), μ1, μ2 and μ3 depend on the phase shift θ generated by the PM and the phase offset φ in the DLI. We use μi,x (i = 1,2,3) to represent the values of μi (i=1,2,3) when the phase offset φ = x degrees.

If φ = 90 degrees in Eq. (2), the three levels {μ1, μ2, μ3} will be given by:

μ1,90=C1PC2Psin(θ),μ2,90=C1Pandμ3,90=C1P+C2Psin(θ).
(3)

If φ = 0 degree in Eq. (2), the three levels {μ1, μ2, μ3} will be given by:

μ1,0=μ3,0=C1P+C2Pcos(θ)andμ2,0=C1P+C2P.
(4)

From Eqs. (3) and (4), the phase shift θ generated by the PM can be estimated by:

tanθ=μ3,90μ2,90μ3,0μ2,90
(5)

Based on Eq. (5), the driver signal amplitude Vpp can be tuned adaptively to achieve a stable phase shift θ0 by monitoring the error signal ε = (μ3,902,90)-tanθ0(μ3,02,90) and driving it to zero.

It should be noted that in the above derivations, the effects of both the non-ideal splitting ratios for the two couplers and the responsivity difference between the two PDs have been taken into account. Consequently, with the proposed control scheme based on Eq. (5), no phase error will be induced by the non-ideal splitting ratios and the responsivity difference. Therefore, the performance of the scheme is inherently robust against these imperfections of practical devices.

3. Experimental results and discussions

The proposed driver signal amplitude control technique is experimentally realized to control a PM to generate a stable 45 degrees phase shift. This module would be essential in the implementation of 8PSK/8QAM transmitter [5

5. X. Zhou, J. Yu, D. Qian, T. Wang, G. Zhang, and P. Magill, “High-Spectral-Efficiency 114-Gb/s Transmission using PolMux-RZ-8PSK modulation format and single-ended digital coherent detection technique,” J. Lightwave Technol. 27(3), 146–152 (2009). [CrossRef]

,8

8. X. Zhou, J. Yu, M. Huang, Y. Shao, T. Wang, P. Magill, M. Cvijetic, L. Nelson, M. Birk, G. Zhang, S. Y. Ten, H. B. Matthew, and S. K. Mishra, “32Tb/s (320x114Gb/s) PDM-RZ-8QAM Transmission over 580km of SMF-28 Ultra-Low-Loss Fiber,” in National Fiber Optic Engineers Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper PDPB4. http://www.opticsinfobase.org/abstract.cfm?URI=NFOEC-2009-PDPB4

], in which a dual-parallel MZM modulator is cascaded with a PM having a phase shift of 45 degrees. In the experiment, the PM is driven by a 10.7 Gb/s binary electrical signal with an adjustable amplitude, ranging from 1.00 V to 1.30 V. Part of the output light from the PM is coupled to the control module shown in Fig. 1. The DLI (Optoplex: Optical DPSK demodulator) has a fixed delay time of 85.4 ps and a tunable phase offset controlled by the external applied voltage Vp. The output electrical signal of the BPD (u2t:BPDV2120) is then measured and asynchronously sampled by an Agilent Digital Sampling Oscilloscope (86100A). The samples are used to construct the histograms.

In the experiment, Vp is adjusted to switch the phase offset φ of the DLI between 0 and 90 degrees alternatively. Figure 2
Fig. 2 Eye diagrams of the BPD output signal when the DLI has the phase offset φ of (a) 0 degree, and (b) 90 degrees.
shows the measured eye diagrams of the BPD output signal when the phase offset is 0 or 90 degrees respectively. The theoretically predicted values in Eq. (3) and Eq. (4) are indicated in these eye diagrams for comparison. In the 0 degree case, only two voltage levels are present since μ1,0 = μ3,0. In the 90 degree case, the upper level μ3,90 and the lower level μ1,90 are symmetrical with respect to the middle level μ2,90.

For the targeted phase shift of 45 degrees, the error signal ε is simplified to μ3,90-μ3,0 by setting tanθ0 = 1 in ε = (μ3,902,90)-tanθ0(μ3,02,90), where θ0 is the desired phase shift of 45 degrees. Figures 3(a)
Fig. 3 Histograms of the sampled BPD output signal when the driver signal amplitude is: (a) 1.00 V, (b) 1.12 V, and (c) 1.26 V. The histograms for the DLI phase offset φ of 0 and 90 degrees are plotted in blue and red respectively.
, 3(b), and 3(c) show the histograms plotted for three particular driver signal amplitudes Vpp of 1.00 V, 1.12 V and 1.26 V, respectively. The voltage levels μ1,90, μ2,90, μ3,90, μ1,0, μ2,0, and μ3,0 are obtained by finding the peak locations in the histograms. For Vpp = 1.00 V, the error signal is negative which is a direct consequence of μ3,90 being smaller than μ3,0. Based on Eq. (5) it can be inferred that the actual phase shift is below 45 degrees. The error signal is close to zero when Vpp is around 1.12 V. The error signal becomes positive when Vpp = 1.26V, indicating that the resultant phase shift is larger than 45 degrees.

Figure 4a
Fig. 4 (a) Error signal ε = μ3,90-μ3,0 as a function of the driver signal amplitude Vpp of a phase modulator. Superimposed eye diagrams (for φ of 0 and 90 degrees) when Vpp is (b)1.26 V, (c)1.14 V, and (d)1.00 V.
depicts the monitored error signal of ε = μ3,90-μ3,0 as a function of the driver signal amplitude Vpp ranging from 1.00 to 1.30 V. Figure 4(b-d) show the superimposed eye diagrams including the cases for both 0 and 90 degrees phase offsets for three Vpp values of 1.26, 1.14, and 1.00 V, respectively. The balance between μ3,90 and μ3,0 can be directly identified in these eye diagrams. As shown in Fig. 4a, the monitored error signal of ε = μ3,90-μ3,0 increases monotonically with Vpp. When Vpp is around 1.14 V, the error signal is approximately equal to zero, indicating that the resultant phase shift approaches the targeted value of 45 degrees. As shown by the two vertical blue lines in Fig. 4(a), the detectable amplitude error is less than ± 0.02 V. Therefore, its corresponding phase deviation is estimated to be ± 0.02 × (45.0/1.14) ≈ ± 0.8 degrees. By increasing the number of samples used in constructing the histograms, the phase precision of the control scheme can be potentially improved. It is worth noting that the proposed technique can be used for stabilizing the phase modulation at an arbitrary value besides the case of 45 degrees demonstrated in this paper. Therefore, the scheme has wide applications in transmitters implementations for various advanced modulation formats [5

5. X. Zhou, J. Yu, D. Qian, T. Wang, G. Zhang, and P. Magill, “High-Spectral-Efficiency 114-Gb/s Transmission using PolMux-RZ-8PSK modulation format and single-ended digital coherent detection technique,” J. Lightwave Technol. 27(3), 146–152 (2009). [CrossRef]

, 8

8. X. Zhou, J. Yu, M. Huang, Y. Shao, T. Wang, P. Magill, M. Cvijetic, L. Nelson, M. Birk, G. Zhang, S. Y. Ten, H. B. Matthew, and S. K. Mishra, “32Tb/s (320x114Gb/s) PDM-RZ-8QAM Transmission over 580km of SMF-28 Ultra-Low-Loss Fiber,” in National Fiber Optic Engineers Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper PDPB4. http://www.opticsinfobase.org/abstract.cfm?URI=NFOEC-2009-PDPB4

, 18

18. K. Fukuchi, “Proposal and Feasibility Study of a 6-Level PSK Modulation Format Based System for 100-Gb/s Migration,” in Optical Fiber Communication Conference and Exposition and The National Fiber Optic Engineers Conference, OSA Technical Digest (CD) (Optical Society of America, 2008), paper OMI6. http://www.opticsinfobase.org/abstract.cfm?URI=OFC-2008-OMI6

], in which stable phase modulation at any arbitrary value is necessary.

4. Conclusions

A dither-free and robust technique is proposed for automatic control of the driver signal amplitude of an optical phase modulator to generate a stable phase shift at any arbitrary value. The proposed technique is analytically proven to be robust against the device imperfections from the delay line interferometer and the balanced photo-detector. The experimental results for stable 45 degrees phase modulation with a phase error of less than ± 0.8 degrees have been successfully demonstrated. The scheme can be used to stabilize the phase shift of a phase modulator at any arbitrary value for optical communication systems employing higher-order modulation formats.

Acknowledgments

The authors would like to acknowledge the generous support of the Hong Kong Government General Research Fund (GRF) under project number PolyU 522009 and the financial support by Project 1-ZV5C and BB-9L of The Hong Kong Polytechnic University, in part by NSFC under grants 60977034 and 11004043, and in part by Shenzhen Municipal Science and Technology Plan Project (contracts JC200903120167A and JC201005260185A).

References and links

1.

J. M. Kahn and K. P. Ho, “Spectral efðciency limits and modulation/detection techniques for DWDM systems,” IEEE J. Sel. Top. Quantum Electron. 10(2), 259–272 (2004). [CrossRef]

2.

A. H. Gnauck and P. J. Winzer, “Optical phase-shift-keyed transmission,” J. Lightwave Technol. 23(1), 115–130 (2005). [CrossRef]

3.

C. R. Fludger, T. Duthel, D. van den Borne, C. Schulien, E. Schmidt, T. Wuth, E. de Man, G. D. Khoe, and H. de Waardt, 10 x 111 Gbit/s, 50 GHz Spaced, POLMUX-RZ-DQPSK Transmission over 2375 km Employing Coherent Equalisation,” in Optical Fiber Communication Conference and Exposition and The National Fiber Optic Engineers Conference, OSA Technical Digest Series (CD) (Optical Society of America, 2007), paper PDP22. http://www.opticsinfobase.org/abstract.cfm?URI=OFC-2007-PDP22

4.

A. H. Gnauck, R. W. Tkach, A. R. Chraplyvy, and T. Li, “High-capacity optical transmission systems,” J. Lightwave Technol. 26(9), 1032–1045 (2008). [CrossRef]

5.

X. Zhou, J. Yu, D. Qian, T. Wang, G. Zhang, and P. Magill, “High-Spectral-Efficiency 114-Gb/s Transmission using PolMux-RZ-8PSK modulation format and single-ended digital coherent detection technique,” J. Lightwave Technol. 27(3), 146–152 (2009). [CrossRef]

6.

Y. Yang, L. Cheng, Z. Li, C. Lu, Q. Xiong, X. Xu, L. Liu, H. Y. Tam, and P. K. A. Wai, “An Optical Differential 8-PSK Modulator Using Cascaded QPSK Modulators, ” in Proceeding of IEEE European Conference on Optical Communication (Vienna, Austria, 2009), Paper P3.19.

7.

G.-W. Lu, T. Sakamoto, and T. Kawanishi, “Rectangular QPSK for generation of optical eight-ary phase-shift keying,” Opt. Express 19(19), 18479–18485 (2011). [CrossRef] [PubMed]

8.

X. Zhou, J. Yu, M. Huang, Y. Shao, T. Wang, P. Magill, M. Cvijetic, L. Nelson, M. Birk, G. Zhang, S. Y. Ten, H. B. Matthew, and S. K. Mishra, “32Tb/s (320x114Gb/s) PDM-RZ-8QAM Transmission over 580km of SMF-28 Ultra-Low-Loss Fiber,” in National Fiber Optic Engineers Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper PDPB4. http://www.opticsinfobase.org/abstract.cfm?URI=NFOEC-2009-PDPB4

9.

A. H. Gnauck, P. J. Winzer, S. Chandrasekhar, X. Liu, B. Zhu, and D. W. Peckham, “Spectrally efficient long-haul WDM transmission using 224-Gb/s polarization-multiplexed 16-QAM,” J. Lightwave Technol. 29(4), 373–377 (2011). [CrossRef]

10.

X. Zhou, J. Yu, M. Huang, Y. Shao, T. Wang, L. Nelson, P. Magill, M. Birk, P. I. Borel, D. W. Peckham, R. Lingle, and B. Zhu, “64-Tb/s, 8 b/s/Hz, PDM-36QAM transmission over 320 km using both pre- and post-transmission digital signal processing,” J. Lightwave Technol. 29(4), 571–577 (2011). [CrossRef]

11.

P. S. Cho, J. B. Khurgin, and I. Shpantzer, “Closed-loop bias control of optical quadrature modulator,” IEEE Photon. Technol. Lett. 18(21), 2209–2211 (2006). [CrossRef]

12.

H. Kawakami, E. Yoshida, and Y. Miyamoto, “Asymmetric dithering technique for bias condition monitoring in optical QPSK modulator,” Electron. Lett. 46(6), 430–431 (2010). [CrossRef]

13.

T. Yoshida, T. Sugihara, K. Uto, H. Bessho, K. Sawada, K. Ishida, K. Shimizu, and T. Mizuochi, “A study on automatic bias control for arbitrary optical signal generation by dual-parallel Mach–Zehnder modulator,” in Proceeding of IEEE European Conference on Optical Communication (Torino, Italy, 2010), Paper Tu.3.A.6.

14.

M. Sotoodeh, Y. Beaulieu, J. Harley, and D. L. McGhan, “Modulator bias and optical power control of optical complex e-field modulators,” J. Lightwave Technol. 29(15), 2235–2248 (2011). [CrossRef]

15.

H. Choi, Y. Takushima, H. Y. Choi, J. H. Chang, and Y. C. Chung, “Modulation-Format-Free Bias Control Technique for MZ Modulator Based on Differential Phasor Monitor,” in Optical Fiber Communication Conference, OSA Technical Digest (CD) (Optical Society of America, 2011), paper JWA033. http://www.opticsinfobase.org/abstract.cfm?URI=OFC-2011-JWA033

16.

W. R. Peng, B. Zhang, X. X. Wu, K. M. Feng, A. E. Willner, and S. Chi, “Compensation for I/Q imbalances and bias deviation of the Mach-Zehnder modulators in direct-detected optical OFDM systems,” IEEE Photon. Technol. Lett. 21(2), 103–105 (2009). [CrossRef]

17.

P. S. Cho and M. Nazarathy, “Bias control for optical OFDM transmitters,” IEEE Photon. Technol. Lett. 22(14), 1030–1032 (2010). [CrossRef]

18.

K. Fukuchi, “Proposal and Feasibility Study of a 6-Level PSK Modulation Format Based System for 100-Gb/s Migration,” in Optical Fiber Communication Conference and Exposition and The National Fiber Optic Engineers Conference, OSA Technical Digest (CD) (Optical Society of America, 2008), paper OMI6. http://www.opticsinfobase.org/abstract.cfm?URI=OFC-2008-OMI6

OCIS Codes
(060.0060) Fiber optics and optical communications : Fiber optics and optical communications
(060.5060) Fiber optics and optical communications : Phase modulation

ToC Category:
Fiber Optics and Optical Communications

History
Original Manuscript: October 18, 2011
Revised Manuscript: November 20, 2011
Manuscript Accepted: November 22, 2011
Published: December 9, 2011

Citation
Yanfu Yang, Chao Lu, Alan Pak Tao Lau, Yong Yao, Yunxu Sun, Jun Jun Xiao, H. Y. Tam, and P. K. A. Wai, "A robust and dither-free technique for controlling driver signal amplitude for stable and arbitrary optical phase modulation," Opt. Express 19, 26353-26358 (2011)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-27-26353


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. J. M. Kahn and K. P. Ho, “Spectral efðciency limits and modulation/detection techniques for DWDM systems,” IEEE J. Sel. Top. Quantum Electron.10(2), 259–272 (2004). [CrossRef]
  2. A. H. Gnauck and P. J. Winzer, “Optical phase-shift-keyed transmission,” J. Lightwave Technol.23(1), 115–130 (2005). [CrossRef]
  3. C. R. Fludger, T. Duthel, D. van den Borne, C. Schulien, E. Schmidt, T. Wuth, E. de Man, G. D. Khoe, and H. de Waardt, 10 x 111 Gbit/s, 50 GHz Spaced, POLMUX-RZ-DQPSK Transmission over 2375 km Employing Coherent Equalisation,” in Optical Fiber Communication Conference and Exposition and The National Fiber Optic Engineers Conference, OSA Technical Digest Series (CD) (Optical Society of America, 2007), paper PDP22. http://www.opticsinfobase.org/abstract.cfm?URI=OFC-2007-PDP22
  4. A. H. Gnauck, R. W. Tkach, A. R. Chraplyvy, and T. Li, “High-capacity optical transmission systems,” J. Lightwave Technol.26(9), 1032–1045 (2008). [CrossRef]
  5. X. Zhou, J. Yu, D. Qian, T. Wang, G. Zhang, and P. Magill, “High-Spectral-Efficiency 114-Gb/s Transmission using PolMux-RZ-8PSK modulation format and single-ended digital coherent detection technique,” J. Lightwave Technol.27(3), 146–152 (2009). [CrossRef]
  6. Y. Yang, L. Cheng, Z. Li, C. Lu, Q. Xiong, X. Xu, L. Liu, H. Y. Tam, and P. K. A. Wai, “An Optical Differential 8-PSK Modulator Using Cascaded QPSK Modulators, ” in Proceeding of IEEE European Conference on Optical Communication (Vienna, Austria, 2009), Paper P3.19.
  7. G.-W. Lu, T. Sakamoto, and T. Kawanishi, “Rectangular QPSK for generation of optical eight-ary phase-shift keying,” Opt. Express19(19), 18479–18485 (2011). [CrossRef] [PubMed]
  8. X. Zhou, J. Yu, M. Huang, Y. Shao, T. Wang, P. Magill, M. Cvijetic, L. Nelson, M. Birk, G. Zhang, S. Y. Ten, H. B. Matthew, and S. K. Mishra, “32Tb/s (320x114Gb/s) PDM-RZ-8QAM Transmission over 580km of SMF-28 Ultra-Low-Loss Fiber,” in National Fiber Optic Engineers Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper PDPB4. http://www.opticsinfobase.org/abstract.cfm?URI=NFOEC-2009-PDPB4
  9. A. H. Gnauck, P. J. Winzer, S. Chandrasekhar, X. Liu, B. Zhu, and D. W. Peckham, “Spectrally efficient long-haul WDM transmission using 224-Gb/s polarization-multiplexed 16-QAM,” J. Lightwave Technol.29(4), 373–377 (2011). [CrossRef]
  10. X. Zhou, J. Yu, M. Huang, Y. Shao, T. Wang, L. Nelson, P. Magill, M. Birk, P. I. Borel, D. W. Peckham, R. Lingle, and B. Zhu, “64-Tb/s, 8 b/s/Hz, PDM-36QAM transmission over 320 km using both pre- and post-transmission digital signal processing,” J. Lightwave Technol.29(4), 571–577 (2011). [CrossRef]
  11. P. S. Cho, J. B. Khurgin, and I. Shpantzer, “Closed-loop bias control of optical quadrature modulator,” IEEE Photon. Technol. Lett.18(21), 2209–2211 (2006). [CrossRef]
  12. H. Kawakami, E. Yoshida, and Y. Miyamoto, “Asymmetric dithering technique for bias condition monitoring in optical QPSK modulator,” Electron. Lett.46(6), 430–431 (2010). [CrossRef]
  13. T. Yoshida, T. Sugihara, K. Uto, H. Bessho, K. Sawada, K. Ishida, K. Shimizu, and T. Mizuochi, “A study on automatic bias control for arbitrary optical signal generation by dual-parallel Mach–Zehnder modulator,” in Proceeding of IEEE European Conference on Optical Communication (Torino, Italy, 2010), Paper Tu.3.A.6.
  14. M. Sotoodeh, Y. Beaulieu, J. Harley, and D. L. McGhan, “Modulator bias and optical power control of optical complex e-field modulators,” J. Lightwave Technol.29(15), 2235–2248 (2011). [CrossRef]
  15. H. Choi, Y. Takushima, H. Y. Choi, J. H. Chang, and Y. C. Chung, “Modulation-Format-Free Bias Control Technique for MZ Modulator Based on Differential Phasor Monitor,” in Optical Fiber Communication Conference, OSA Technical Digest (CD) (Optical Society of America, 2011), paper JWA033. http://www.opticsinfobase.org/abstract.cfm?URI=OFC-2011-JWA033
  16. W. R. Peng, B. Zhang, X. X. Wu, K. M. Feng, A. E. Willner, and S. Chi, “Compensation for I/Q imbalances and bias deviation of the Mach-Zehnder modulators in direct-detected optical OFDM systems,” IEEE Photon. Technol. Lett.21(2), 103–105 (2009). [CrossRef]
  17. P. S. Cho and M. Nazarathy, “Bias control for optical OFDM transmitters,” IEEE Photon. Technol. Lett.22(14), 1030–1032 (2010). [CrossRef]
  18. K. Fukuchi, “Proposal and Feasibility Study of a 6-Level PSK Modulation Format Based System for 100-Gb/s Migration,” in Optical Fiber Communication Conference and Exposition and The National Fiber Optic Engineers Conference, OSA Technical Digest (CD) (Optical Society of America, 2008), paper OMI6. http://www.opticsinfobase.org/abstract.cfm?URI=OFC-2008-OMI6

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

Figures

Fig. 1 Fig. 2 Fig. 3
 
Fig. 4
 

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited