Polarization-independent acoustically tunable optical filter

Abstract

A polarization-independent acoustically tunable optical filter is described, with 1.3 nm bandwidth and 145 nm tuning range demonstrated about a center wavelength of 1525 nm. Filtered and unfiltered beams exit from different ports of this 2×2 integrated-optic structure fabricated on a LiNbO3 substrate. The filter conversion efficiency was 97% for unpolarized light, limited by imperfect splitting of the directional-coupler polarizing beamsplitters. Using an unpolarized, 105-nm-wide light-emitting diode as the optical source, 16 dB isolation of the filtered port was achieved, both with respect to the nearest nulls and the remote background spectrum.

An Explicit Analytical Solution for the Transcendental Equation Describing Saturated Erbium-Doped Fiber Amplifiers

“…A maximum signal gain of G f 25 dB is 60 obtained for q s 15, which is considered to represent a w x regime below that of self-saturation caused by ASE 6 , w x 7 . These plots provide information on the gain tilt and flatness, as well as on the remaining output pump power Ž at s 1480 nm e.g., for q s 15, we have G s y3 dB, 11 o ut i n . or p s p r2 s 7.5 .…”

<title>Review of high-speed wavelength tunable filters/receivers for broadband switching networks</title>

“…--Filter/coupler or demultiplexer only: one of the powerfulness of the WDM network is its wavelength add/drop function, which can increase the system's variability and flexibility, as demonstrated by AOTF [12].…”

“…So far, AOTF [12,[69][70][71][72] is known to be unique among the candidates for wavelengthselective routing devices, because it is capable of simultaneously routing many wavelength channels, selected at random, with a very large tuning range.…”

<title>Performance evaluation of a multi-Gbit/s WDM optical packet network with physical ring topology and multisubcarrier header encoding</title>

“…By now, integrated optic AOTFs have evolved considerably. AOTFs have been demonstrated on the more practical X-cut crystal orientation in LiNbO3 [18]; two-stage AOTFs have been fabricated to reduce sidelobe intensities in the filter transfer function [19]; and polarization-diversity AOTFs have been fabricated [20]. Further, polarization diversity AOTFs have been demonstrated which offer the possibility of using the device as a wavelength add-drop multiplexer [20,21].…”