Resonance control of a silicon micro-ring resonator modulator under high-speed operation using the intrinsic defect-mediated photocurrent Academic Article uri icon

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abstract

  • A method to stabilize the resonance wavelength of a depletion-type silicon micro-ring resonator modulator during high-speed operation is described. The method utilizes the intrinsic defect-mediated photo-absorption of a silicon waveguide and results in a modulator chip fabrication process that is free of heterogeneous integration (for example using germanium), thus significantly reducing the complexity and cost of manufacture. Residual defects, present after p-n junction formation, are found to produce an adequate photocurrent for use as a feedback signal, while an integrated heater is used to compensate for thermal drift via closed-loop control. The photocurrent is measured by a source-meter, which simultaneously provides a DC bias to the integrated heater during high-speed operation. A drop-port or an integrated extrinsic detector is not needed. This feedback control method is experimentally demonstrated via a computer-aided proportional-integral-differential loop. The resonance locking is validated for 12.5 Gb/s intensity modulation in a back-to-back bit-error-rate measurement. The stabilization method described is not limited to a specific modulator design and is compatible with speeds greatly in excess of 12.5 Gb/s, in contrast to the bandwidth limitation of other stabilization methods that rely on intrinsic photo-carrier generation through non-linear processes such as two-photon-absorption. Further, the use of intrinsic defects present after standard fabrication insures that no excess loss is associated with this stabilization method.

authors

  • Wang, Zhao
  • Paez, Dixon
  • El-Rahman, Ahmed I Abd
  • Wang, Peng
  • Dow, Liam
  • Cartledge, John C
  • Knights, Andrew

publication date

  • October 2, 2017