Ultrafast two-photon absorption optical thresholding of spectrally coded pulses
نویسندگان
چکیده
Ž . We report studies on two-photon absorption TPA GaAs p-i-n waveguide photodetectors as optical thresholders for Ž . proposed ultrashort pulse optical code-division multiple-access CDMA systems. For either chirped optical pulses or spectrally phase coded pseudonoise bursts, the TPA photocurrent response reveals a strong pulseshape dependence and shows good agreement with theoretical predictions and results from conventional SHG measurements. The performance limits of the TPA optical thresholders set by the encoded bandwidth in the spectral encoding-decoding process are also discussed based on numerical simulations. Our results show the feasibility of applying such devices as nonlinear intensity discriminators in ultrahigh-speed optical network applications. q 1999 Elsevier Science B.V. All rights reserved. PACS: 42.79.Sz; 42.50.Hz; 42.65.Re; 85.60.Gz
منابع مشابه
Ultrafast all-optical switching by cross-absorption modulation in silicon wire waveguides.
We describe the use of two-photon absorption in submicron silicon wire waveguides for all-optical switching by cross-absorption modulation. Optical pulses of 3.2 ps were successfully converted from high power pump to low power continuous-wave signal with a fast recovery time. High speed operation was based on the induced optical absorption from non-degenerate two-photon absorption inside the wa...
متن کاملSpectrally phase-coded O-CDMA [Invited]
A summary of recent progress in our spectrally phase-coded O-CDMA system is presented, including multiuser Gbits/s system demonstrations, error-free ultrafast fiber transmission over 50 km single-mode fiber with 500 fs pulses, code translation demonstrations as may be required in a multipoint network implementation, and experimental studies of potential security issues in O-CDMA. © 2007 Optical...
متن کاملUltrafast Kerr-induced all-optical wavelength conversion in silicon waveguides using 1.55 mum femtosecond pulses.
The propagation of 300 femtosecond optical pulses in Silicon-on Insulator waveguides has been studied by means of a pump-probe set-up. The ultrafast pulses allowed the observation of large Kerr-induced red and blue shifts (9nm and 15nm, respectively) of the probe signal depending on the delay between pump (1554nm) and probe (1683nm) pulses. A numerical model taking into account the Kerr effect,...
متن کاملTwo-photon vibrational excitation of air by long-wave infrared laser pulses
Ultrashort long-wave infrared (LWIR) laser pulses can resonantly excite vibrations in N2 and O2 through a twophoton transition. The absorptive vibrational component of the ultrafast optical nonlinearity grows in time, starting smaller than but quickly surpassing the electronic, rotational, and vibrational refractive components. The growth of the vibrational component results in a novel mechanis...
متن کاملTunable Broadband Nonlinear Optical Properties of Black Phosphorus Quantum Dots for Femtosecond Laser Pulses
Broadband nonlinear optical properties from 500 to 1550 nm of ultrasmall black phosphorus quantum dots (BPQDs) have been extensively investigated by using the open-aperture Z-scan technique. Our results show that BPQDs exhibit significant nonlinear absorption in the visible range, but saturable absorption in the near-infrared range under femtosecond excitation. The calculated nonlinear absorpti...
متن کامل