Abstract
A cascaded system of two acousto-optical cells is proposed for equalization of multichannel optical signal satisfying coarse wavelength-division multiplexing standard. Two similar acousto-optical modulators for unpolarized light on the basis of 10 degrees-cut paratellurite crystals were used in a free-space gap of a fiber line. The system controlled intensity of several optical carriers in the spectral range from 1200 to 1700 nm. The device was tested in a four-channel regime of operation in the range 1510-1570 nm. Overall optical insertion losses did not exceed -2 dB and less than 1 W electric power per channel was necessary for -20 dB intensity attenuation of the signal in a continuous operation mode. Compensation for birefringence in paratellurite provided diffraction regime that was insensitive to polarization of light. Interchannel crosstalk was less than -10 dB.
Highlights
Development of optical communication networks with the use of wavelength-division multiplexing (WDM) technology required new types of spectral devices for control of multichannel light beams
Acousto-optical tunable filters (AOTFs) may not be directly used in Dense WDM networks because their passband is wider than the channel spacing
We developed a prototype of an AO equalizer for Coarse WDM (CWDM) optical networks
Summary
Development of optical communication networks with the use of wavelength-division multiplexing (WDM) technology required new types of spectral devices for control of multichannel light beams. Acousto-optical (AO) modulators are good candidates for spectral equalization in WDM systems because they can operate in a multifrequency mode: different optical channels are independently controlled by corresponding ultrasonic waves in the same crystal. These devices are compact and reliable and they provide a high operation rate and a low power consumption [2, 3]. We used a filtering configuration of anisotropic diffraction with polarization splitting in a modulator for unpolarized light [7] Former analysis of this scheme did not take into consideration inevitable splitting of the transmitted beam because of birefingence of the material.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
