TE-TM mode conversion by interaction between elastic surface waves and a laser beam on a metal-diffused optical waveguide

Abstract

TEm-TMn mode conversion by electro-optic and acousto-optic effects in a metal-diffused optical waveguide is described theoretically. Elastic surface waves and laser beams propagate along the X axis on Y-cut LiNbO3 single crystals, i.e., interactions are collinear. We predict completely the TE1-TM1 mode conversion at an elastic surface wave power of 33 mW along an interaction length of 5 mm with a width of 1 mm.

Tunable acoustooptic reflection filters in LiNbO/sub 3/ without a Doppler shift

“…In this section we shall consider the possible crystal orientations for this device [3], [6]. Bulk acoustooptic interactions are discussed in [ 113, [ 121. Higher strain can be achieved with a given acoustic power if guided acoustic waves are used.…”

“…Moreover, when the light is reflected at the external laser mirror and passes through the filter for a second time in the reverse direction, it experiences again the same undesired frequency shift, thus it would provide feedback to the gain medium at a twice Doppler-shifted optical frequency. Efficient coupling between the two modes can be achieved by employing a periodic phase matched interaction, induced here by an acoustic wave via the elastooptic effect [3]. Hence, the output light of the two cascaded acoustooptic filters is not shifted in frequency, Manuscripts filters can be readily tuned over ranges of the order of AXT/X -1/10 by simply tuning the acoustic frequency and thus the period of the coupling index grating.…”

Noise tolerance in wavelength-selective switching of optical differential quadrature-phase-shift-keying pulse train by collinear acousto-optic devices

“…Acousto-optic (AO) devices using interaction between optical guided waves and surface acoustic waves (SAWs) have been studied for filtering and switching of WDM signals [4][5][6][7][8][9][10][11][12][13][14][15]. Recently, in lowpower-consuming WDM networks, reconfigurable optical add/drop multiplexers (ROADMs) have been regarded as key devices and various configurations using collinear AO devices [14,16], microelectromechanical systems (MEMS) [17,18], and liquidcrystal-on-silicon (LCOS) switches [17,19] have been investigated.…”

Wavelength-Division-Multiplexed Photonic Switching System Using Integrated Acoustooptic Switches

“…The mode conversion between fundamental even and odd modes is utilized, which results in switching in the same polarization. Compared to other kinds of collinear AO devices which use TE-TM mode conversion, 9,12) our devices have the advantage of polarization conservation through switching. Moreover, our devices do not require anisotropy for the waveguide material, and the control SAW frequency is designed in a wide range from around 10 MHz to 2 GHz.…”