OSA's Digital Library

Optics Express

Optics Express

  • Editor: Andrew M. Weiner
  • Vol. 21, Iss. 12 — Jun. 17, 2013
  • pp: 14368–14376
« Show journal navigation

Suppression of even-order photodiode distortions via predistortion linearization with a bias-shifted Mach-Zehnder modulator

Vincent J. Urick, Meredith N. Hutchinson, Joseph M. Singley, Jason D. McKinney, and Keith J. Williams  »View Author Affiliations


Optics Express, Vol. 21, Issue 12, pp. 14368-14376 (2013)
http://dx.doi.org/10.1364/OE.21.014368


View Full Text Article

Acrobat PDF (833 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

A new technique to cancel photodiode-induced even-order distortion in microwave photonic links is demonstrated. A single Mach-Zehnder modulator, biased slightly away from the quadrature point, is shown to suppress photodiode second-order intermodulation distortion in excess of 40 dB without affecting the fundamental power. The technique is theoretically described with supporting experimental results.

© 2013 OSA

1. Introduction

In this work we demonstrate cancellation of photodiode even-order distortion via predisortion linearization with a MZM biased slightly away from quadrature. This technique employs a single fiber run and a single photodiode. Improvements in carrier-to-intermodulation ratio (CIR) upwards of 40 dB are reported. A theoretical analysis of the technique is provided in Section 2, where closed-form expressions are used to describe the MZM nonlinearities and a Taylor-series expansion is applied to the photodiode. Experimental data supporting the theory are presented in Section 3. Implications of this work are discussed in Section 4.

2. Theory

2.1 Link with ideal photodiode

The treatment here will assume a small-signal two-tone stimulus with equal amplitude tones, thus ϕ1=ϕ2=ϕ<<1. A small-signal approximation allows for the Bessel functions to be written as Jn(ϕ)ϕn/(2nn!). These conditions can be applied to Eq. (2) to yield the fundamental photocurrents

Ifund,mzm=ϕIdc,qsin(ϕdc)[sin(Ω1t)+sin(Ω2t)].
(3)

Assuming all of the current is delivered to a load with resistance R, the average output power for both of the fundamentals is Pfund,mzm=ϕ2Idc,q2sin2(ϕdc)R/2. The work here concentrates on even-order distortion. The largest small-signal distortion in Eq. (2) is second-order intermodulation distortion (IMD2) at frequencies |f1±f2| given by the first two double summations in Eq. (2c) with n=p=0. The small-signal photocurrent for these two terms is
Iimd2,mzm=±ϕ2Idc,qcos(ϕdc)2cos[(Ω2Ω1)t].
(4)
The average power associated with Eq. (4) is Pimd2,mzm=ϕ4Idc,q2cos2(ϕdc)R/8. Finally, the OIP2 due to MZM-generated IMD2 is
OIP2mzm=2sin4(ϕdc)cos2(ϕdc)Idc,q2R.
(5)
As given by Eq. (5) and detailed previously [1

1. V. J. Urick, J. F. Diehl, M. N. Draa, J. D. McKinney, and K. J. Williams, “Wideband analog photonic links: some performance limits and considerations for multi-octave limitations,” Proc. SPIE 8259, 1–14 (2012). [CrossRef]

], small deviations from quadrature bias can significantly degrade the OIP2. In fact, the tolerance on MZM bias can be quite stringent to maintain third-order-limited performance in multi-octave links.

2.2 Photodiode distortion

OIP2pd=a14R2a22.
(10)

2.3 Combined response

3. Experiments

The structure shown in Fig. 2 was constructed using two 100-mW semiconductor lasers (EM4, Inc.) at 1548 nm and 1560 nm. The two MZMs (EOSPACE) exhibited 20 GHz of analog bandwidth and had nearly equal Vπ(Ω). The two signal generators were set at f1 = 0.9 GHz and f2 = 1.1 GHz. With the variable optical attenuators set to output the same average optical power, the signal generators were adjusted to establish the same modulation depth on each laser. The photodiode being examined was an Applied Optoelectronics PD3000 with 3-dB bandwidth of about 3-GHz. The photodiode was reversed biased with 1 V and the OIP2 was measured by sweeping the input power at f1 and f2. The measured OIP2 = 13.5 dBm due to IMD2 at 2.0 GHz for an average photocurrent of Idc = 3.0 mA as shown in Fig. 3
Fig. 3 Measured OIP2 due to intermodulation distortion for the photodiode at 3 mA average photocurrent. Shown are the measured fundamentals (circles), the measured IMD2 (squares), and the first- and second-order fits with slopes m = 1 and m = 2, respectively.
. Also measured were OIP2 = 13.8 and 13.5 dBm at Idc = 2.5 and 3.5 mA, respectively.

4. Summary and conclusions

A new technique to suppress photodiode even-order distortion has been demonstrated. The method employs a single-output MZM with a single photodiode, where the bias of the MZM is adjusted to achieve cancellation of photodiode distortion. The amplitude of the MZM-induced even order distortion is symmetric about quadrature but the phase of the even-order distortion shifts by 180 degrees. However, the MZM-generated fundamental phase is constant on either side of quadrature. Therefore, if the fundamental is assumed to drive the photodiode from which the photodiode-induced even-order distortion originates, then the phase and amplitude of the MZM-generated even-order distortion can be adjusted to cancel that from the photodiode. The cancellation bias phase depends on the magnitude of the photodiode distortion and the average photocurrent at quadrature bias.

References and links

1.

V. J. Urick, J. F. Diehl, M. N. Draa, J. D. McKinney, and K. J. Williams, “Wideband analog photonic links: some performance limits and considerations for multi-octave limitations,” Proc. SPIE 8259, 1–14 (2012). [CrossRef]

2.

V. J. Urick, A. S. Hastings, J. D. McKinney, P. S. Devgan, K. J. Williams, C. Sunderman, J. F. Diehl, and K. Colladay, “Photodiode linearity requirements for radio-frequency photonics and demonstration of increased performance using photodiode arrays,” in 2008IEEE International Meeting on Microwave Photonics Digest, pp. 86–89. [CrossRef]

3.

A. Joshi, “Highly linear dual photodiodes for Ku-Band applications,” in 2009IEEE Avionics Fiber Optics and Photonics Conference Digest, pp. 9–10.

4.

Y. Fu, H. Pan, and J. C. Campbell, “Photodiodes with monolithically integrated Wilkinson power combiner,” IEEE J. Quantum Electron. 46(4), 541–545 (2010). [CrossRef]

5.

S. Itakura, K. Sakai, T. Nagatsuka, E. Ishimura, M. Nakaji, H. Otsuka, K. Mori, and Y. Hirano, “High-current backside-illuminated photodiode array module for optical analog links,” J. Lightwave Technol. 28(6), 965–971 (2010). [CrossRef]

6.

Y. Fu, H. Pan, Z. Li, and J. Campbell, “High linearity photodiode array with monolithically integrated Wilkinson power combiner,” in 2010IEEE International Meeting on Microwave Photonics Digest, pp. 111–113. [CrossRef]

7.

A. S. Hastings, V. J. Urick, C. Sunderman, J. F. Diehl, J. D. McKinney, D. A. Tulchinsky, P. S. Devgan, and K. J. Williams, “Suppression of even-order photodiode nonlinearities in multioctave photonic links,” J. Lightwave Technol. 26(15), 2557–2562 (2008). [CrossRef]

8.

B. H. Kolner and D. W. Dolfi, “Intermodulation distortion and compression in an integrated electrooptic modulator,” Appl. Opt. 26(17), 3676–3680 (1987). [CrossRef] [PubMed]

9.

K. J. Williams and R. D. Esman, “Design considerations for high-current photodetectors,” J. Lightwave Technol. 17(8), 1443–1454 (1999). [CrossRef]

10.

Y. Fu, H. Pan, Z. Li, A. Beling, and J. C. Campbell, “Characterizing and modeling nonlinear intermodulation distortions in modified uni-traveling carrier photodiodes,” IEEE J. Quantum Electron. 47(10), 1312–1319 (2011). [CrossRef]

11.

A. Ramaswamy, N. Nunoya, K. J. Williams, J. Klamkin, M. Piels, L. A. Johansson, A. S. Hastings, L. A. Coldren, and J. E. Bowers, “Measurement of intermodulation distortion in high-linearity photodiodes,” Opt. Express 18(3), 2317–2324 (2010). [CrossRef] [PubMed]

12.

M. N. Draa, A. S. Hastings, and K. J. Williams, “Comparison of photodiode nonlinearity measurement systems,” Opt. Express 19(13), 12635–12645 (2011). [CrossRef] [PubMed]

OCIS Codes
(040.5160) Detectors : Photodetectors
(060.0060) Fiber optics and optical communications : Fiber optics and optical communications
(060.2360) Fiber optics and optical communications : Fiber optics links and subsystems
(060.5625) Fiber optics and optical communications : Radio frequency photonics

ToC Category:
Detectors

History
Original Manuscript: April 3, 2013
Revised Manuscript: May 24, 2013
Manuscript Accepted: May 29, 2013
Published: June 10, 2013

Citation
Vincent J. Urick, Meredith N. Hutchinson, Joseph M. Singley, Jason D. McKinney, and Keith J. Williams, "Suppression of even-order photodiode distortions via predistortion linearization with a bias-shifted Mach-Zehnder modulator," Opt. Express 21, 14368-14376 (2013)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-21-12-14368


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. V. J. Urick, J. F. Diehl, M. N. Draa, J. D. McKinney, and K. J. Williams, “Wideband analog photonic links: some performance limits and considerations for multi-octave limitations,” Proc. SPIE8259, 1–14 (2012). [CrossRef]
  2. V. J. Urick, A. S. Hastings, J. D. McKinney, P. S. Devgan, K. J. Williams, C. Sunderman, J. F. Diehl, and K. Colladay, “Photodiode linearity requirements for radio-frequency photonics and demonstration of increased performance using photodiode arrays,” in 2008IEEE International Meeting on Microwave Photonics Digest, pp. 86–89. [CrossRef]
  3. A. Joshi, “Highly linear dual photodiodes for Ku-Band applications,” in 2009IEEE Avionics Fiber Optics and Photonics Conference Digest, pp. 9–10.
  4. Y. Fu, H. Pan, and J. C. Campbell, “Photodiodes with monolithically integrated Wilkinson power combiner,” IEEE J. Quantum Electron.46(4), 541–545 (2010). [CrossRef]
  5. S. Itakura, K. Sakai, T. Nagatsuka, E. Ishimura, M. Nakaji, H. Otsuka, K. Mori, and Y. Hirano, “High-current backside-illuminated photodiode array module for optical analog links,” J. Lightwave Technol.28(6), 965–971 (2010). [CrossRef]
  6. Y. Fu, H. Pan, Z. Li, and J. Campbell, “High linearity photodiode array with monolithically integrated Wilkinson power combiner,” in 2010IEEE International Meeting on Microwave Photonics Digest, pp. 111–113. [CrossRef]
  7. A. S. Hastings, V. J. Urick, C. Sunderman, J. F. Diehl, J. D. McKinney, D. A. Tulchinsky, P. S. Devgan, and K. J. Williams, “Suppression of even-order photodiode nonlinearities in multioctave photonic links,” J. Lightwave Technol.26(15), 2557–2562 (2008). [CrossRef]
  8. B. H. Kolner and D. W. Dolfi, “Intermodulation distortion and compression in an integrated electrooptic modulator,” Appl. Opt.26(17), 3676–3680 (1987). [CrossRef] [PubMed]
  9. K. J. Williams and R. D. Esman, “Design considerations for high-current photodetectors,” J. Lightwave Technol.17(8), 1443–1454 (1999). [CrossRef]
  10. Y. Fu, H. Pan, Z. Li, A. Beling, and J. C. Campbell, “Characterizing and modeling nonlinear intermodulation distortions in modified uni-traveling carrier photodiodes,” IEEE J. Quantum Electron.47(10), 1312–1319 (2011). [CrossRef]
  11. A. Ramaswamy, N. Nunoya, K. J. Williams, J. Klamkin, M. Piels, L. A. Johansson, A. S. Hastings, L. A. Coldren, and J. E. Bowers, “Measurement of intermodulation distortion in high-linearity photodiodes,” Opt. Express18(3), 2317–2324 (2010). [CrossRef] [PubMed]
  12. M. N. Draa, A. S. Hastings, and K. J. Williams, “Comparison of photodiode nonlinearity measurement systems,” Opt. Express19(13), 12635–12645 (2011). [CrossRef] [PubMed]

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 Fig. 5
 

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited