Publications by authors named "Seyed Ehsan Jamali Mahabadi"

We use the drift-diffusion equations to calculate the responsivity of a modified uni-traveling carrier (MUTC) photodetector (PD) with a frequency comb input that is generated by a series of short optical pulses. We first use experimental results for the responsivity of the MUTC PD to obtain an empirical model of bleaching in pulsed mode. We incorporate our empirical bleaching model into a drift-diffusion model to calculate the impact of nonlinearity in an MUTC PD on RF-modulated electro-optic frequency combs.

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Article Synopsis
  • The study analyzes how nonlinearity affects two types of photodetectors (PDs)—a standard PD and a modified uni-traveling carrier (MUTC) PD—when using an RF-modulated frequency comb generated by 100-fs optical pulses.
  • It focuses on nonlinear saturation caused by high peak-to-average-power ratios and examines second- and third-order intermodulation distortion products (IMD2 and IMD3) for each comb line rather than just general signals.
  • Findings indicate that the MUTC PD experiences more significant nonlinear distortion at higher frequencies compared to the standard PD.
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A major design goal for femtosecond fiber lasers is to increase the output power but not at the cost of increasing the noise level or narrowing the bandwidth. Here, we perform a computational study to optimize the cavity design of a femtosecond fiber laser that is passively modelocked with a semiconductor saturable absorbing mirror (SESAM). We use dynamical methods that are more than a thousand times faster than standard evolutionary methods.

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We describe a procedure to calculate the impulse response and phase noise of high-current photodetectors using the drift-diffusion equations while avoiding computationally expensive Monte Carlo simulations. We apply this procedure to a modified uni-traveling-carrier (MUTC) photodetector. In our approach, we first use the full drift-diffusion equations to calculate the steady-state photodetector parameters.

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