Influence of carrier lifetime on performance of silicon p-i-n variable optical attenuators fabricated on submicrometer rib waveguides.

We investigated influence of carrier lifetime on performance of silicon (Si) p-i-n variable optical attenuators (VOAs) on submicrometer Si rib waveguides. VOAs were fabricated with and without intentional implantation of lattice defects into their intrinsic region. Carrier lifetime was measured by pulse responses for normal incidence of picosecond laser pulse of 775 nm to the VOA, as approximately 1 ns and approximately 7 ns for the VOAs with and without defects, respectively. Carrier lifetime is determined by the sum of surface recombination and Auger recombination for VOAs without defects, while Schockley-Read-Hall recombination is dominant for the VOA with defects. As a result, attenuation efficiency (dB/mA) is 0.2-0.7 and 0.04-0.1, while 3-dB bandwidth is 40-100 MHz and over 200 MHz for the VOAs with and without defects, respectively. There is a trade-off relation between attenuation and response speed of the VOAs with respect to carrier lifetime i.e., attenuation efficiency is linearly proportional to the carrier lifetime, whereas response speed is inversely proportional to it.

[1]  Dieter K. Schroder,et al.  Carrier lifetimes in silicon , 1997 .

[2]  R. Soref,et al.  Electrooptical effects in silicon , 1987 .

[3]  Graham T. Reed,et al.  Low-loss, single-model optical phase modulator in SIMOX material , 1994 .

[4]  Alexander Fang,et al.  An all-silicon Raman laser , 2005, Nature.

[5]  Keiji Kishine,et al.  10.3 Gbit/s burst-mode PIN-TIA module with high sensitivity, wide dynamic range and quick response , 2008 .

[6]  On the effective carrier lifetime of a silicon p-i-n diode optical modulator , 2008 .

[7]  J. Dziewior,et al.  Auger coefficients for highly doped and highly excited silicon , 1977 .

[8]  Masaya Ichimura,et al.  Interface recombination velocity of silicon-on-insulator wafers measured by microwave reflectance photoconductivity decay method with electric field , 2003 .

[9]  H. Fischer,et al.  Carrier lifetime in silicon and its impact on solar cell characteristics , 1979 .

[10]  X.M. Zhang,et al.  Linear MEMS variable optical attenuator using reflective elliptical mirror , 2005, IEEE Photonics Technology Letters.

[11]  Hon Ki Tsang,et al.  Tapered silicon waveguides for low insertion loss highly-efficient high-speed electronic variable optical attenuators , 2003, OFC 2003 Optical Fiber Communications Conference, 2003..

[12]  Masayuki Okuno,et al.  PLC type compact variable optical attenuator for photonic transport network , 1998 .

[13]  J. Woo,et al.  Lifetime of photogenerated carriers in silicon-on-insulator rib waveguides , 2005 .

[14]  B Jalali,et al.  Influence of nonlinear absorption on Raman amplification in Silicon waveguides. , 2004, Optics express.

[15]  Qianfan Xu,et al.  Micrometre-scale silicon electro-optic modulator , 2005, Nature.

[16]  Jan Linnros,et al.  Carrier lifetime measurements using free carrier absorption transients. I. Principle and injection dependence , 1998 .

[17]  T. Watanabe,et al.  Applications of Low-loss Silicon Photonic Wire Waveguides with Carrier Injection Structures , 2007, 2007 4th IEEE International Conference on Group IV Photonics.

[18]  B T Smith,et al.  Improved efficiency Si-photonic attenuator. , 2008, Optics express.