Improving the Performance of Sampled-Grating DBR Laser-Based Analog Optical Transmitters

In this paper, the available analog link performance of integrated transmitters containing a sampled-grating distributed Bragg reflector laser, a semiconductor optical amplifier, and a modulator is evaluated. It is found that to provide a link gain and a low-noise figure, an RF preamplifier is required, and for this reason, spurious-free dynamic range (SFDR) including a preamplifier has been evaluated. An SFDR of 110-dBHz2/3, a noise figure of 5.4 dB, and link gain of 6.9 dB at 5 GHz is obtained. It is further investigated how link SFDR can be improved by linearization techniques. Two novel approaches are proposed and demonstrated: first, predistortion by extraction of nonlinear components from an integrated second modulator exposed to the same wavelength, optical power and temperature for matched nonlinear terms; second, a novel linearized modulator configuration balancing electroabsorption and Mach-Zehnder modulation that can reach a null for both second- and third-order intermodulation products at a single bias point.

[1]  Paul K. L. Yu,et al.  Concise RF equivalent circuit model for electroabsorption modulators , 2000 .

[2]  W.S.C. Chang,et al.  Increased linear dynamic range by low biasing the Mach-Zehnder modulator , 1993, IEEE Photonics Technology Letters.

[3]  Gary E. Beth.  Linearized Modulator for Suboctave-Bandpass Optical Analog Links , 1994 .

[4]  A. Ehrhardt,et al.  Turn-key-ready wavelength-, repetition rate- and pulsewidth-tunable femtosecond hybrid modelocked semiconductor laser , 1995 .

[5]  Larry A. Coldren,et al.  Dynamic range of widely tunable sampled-grating DBR lasers , 2002 .

[6]  J. Barton,et al.  Widely tunable directly modulated sampled-grating DBR lasers , 2002, Optical Fiber Communication Conference and Exhibit.

[7]  Larry A. Coldren,et al.  Sampled-grating DBR laser-based analog optical transmitters , 2003 .

[8]  M. M. Howerton,et al.  Broad-band unamplified optical link with RF gain using a LiNbO3 modulator , 1999, IEEE Photonics Technology Letters.

[9]  G. Fish,et al.  Widely tunable sampled grating DBR laser with integrated electroabsorption modulator , 1999, IEEE Photonics Technology Letters.

[10]  Bahram Jalali,et al.  Adaptive electronic linearization of fiber optic links , 2003, OFC 2003 Optical Fiber Communications Conference, 2003..

[11]  J. Barton,et al.  Direct intensity modulation in sampled-grating DBR lasers , 2002, IEEE Photonics Technology Letters.

[12]  L.A. Coldren,et al.  10 Gb/s Mach-Zehnder modulator integrated with widely-tunable sampled grating DBR laser , 2004, Optical Fiber Communication Conference, 2004. OFC 2004.

[13]  L. D. Westbrook,et al.  Improved signal-to-noise ratio in gain-levered InGaAs/InP MQW lasers , 1993 .

[14]  L. D. Westbrook,et al.  Reduced intermodulation-free dynamic range in gain-lever lasers , 1993 .

[15]  J. Barton,et al.  Relative intensity noise measurements of a widely tunable sampled-grating DBR laser , 2002, IEEE Photonics Technology Letters.

[16]  Charles Howard Cox,et al.  Analog Optical Links: Theory and Practice , 2006 .

[17]  J.E. Mitchell,et al.  Interchannel distortion suppression for broadband wireless over fibre transmission using feed-forward linearised DFB laser , 2004, 2004 IEEE International Topical Meeting on Microwave Photonics (IEEE Cat. No.04EX859).

[18]  T. Tanbun-Ek,et al.  Linearization of 1.55-/spl mu/m electroabsorption modulated laser by distortion emulation and reversal for 77-channel CATV transmission , 1998, IEEE Photonics Technology Letters.

[19]  G. Fish,et al.  Widely tunable electroabsorption-modulated sampled-grating DBR laser transmitter , 2002 .

[20]  Uziel Koren,et al.  Electric field screening by photogenerated holes in multiple quantum wells: A new mechanism for absorption saturation , 1990 .

[21]  Larry A. Coldren,et al.  High optical power electroabsorption waveguide modulator , 2003 .

[22]  Edward I. Ackerman,et al.  RF fiber-optic link performance , 2001 .

[23]  Ming C. Wu,et al.  Velocity-matched distributed photodetectors and balanced photodetectors with p-i-n photodiodes , 2001 .

[24]  A. Allerman,et al.  Cascade vertical cavity surface emitting laser arrays , 2002, The 15th Annual Meeting of the IEEE Lasers and Electro-Optics Society.

[25]  J.S. Barton,et al.  Tailorable chirp using integrated Mach-Zehnder modulators with tunable sampled grating distributed Bragg reflector lasers , 2002, IEEE 18th International Semiconductor Laser Conference.

[26]  John Lehrer Zyskind,et al.  Predistortion of electroabsorption modulators for analog CATV systems at 1.55 /spl mu/m , 1997 .

[27]  R.J. Ram,et al.  Broadband, directly modulated analog fiber link with positive intrinsic gain and reduced noise figure , 1998, International Topical Meeting on Microwave Photonics. Technical Digest (including High Speed Photonics Components Workshop) (Cat. No.98EX181).

[28]  H. Roussell,et al.  Input impedance conditions for minimizing the noise figure of an analog optical link , 1997, 1997 IEEE MTT-S International Microwave Symposium Digest.

[29]  Kerry J. Vahala,et al.  The optical gain lever: A novel gain mechanism in the direct modulation of quantum well semiconductor lasers , 1989 .

[30]  L. Coldren,et al.  Theory, design, and performance of extended tuning range semiconductor lasers with sampled gratings , 1993 .