High‐performance electro‐optic polarisation conversion type modulator for short‐wavelength light using periodically poled MgO:LiNbO ₃

Abstract

High-performance electro-optic polarisation conversion type modulator for short-wavelength light using periodically poled MgO:LiNbO 3 T. Inoue and T. SuharaAn electro-optic (EO) polarisation conversion type modulator for short-wavelength light using periodically poled MgO:LiNbO 3 is fabricated and the characteristics are evaluated using a tunable GaN laser. High-quality domain-inverted gratings with 3.6 μm were obtained over a 1.0 × 1.0 mm 2 area. The maximum conversion efficiency, as high as 91%, was obtained. The wavelength bandwidth was 0.7 nm, which was in good agreement with the calculated value, and high wavelength selectivity was obtained.

Electro-optic polarization conversion type modulator using periodically poled 8 mol % MgO doped congruent LiTaO3

“…7, the wavelength acceptance bandwidth, 2Δλ ≅ 5λ 2 =2πL(n eg − n og ), is expected to be ∼17 nm, which is much broader than that of the MgO:LN device (2Δλ ∼ 0.7 nm for λ = 407 nm and L = 1.0 mm). 14) We demonstrated an EO polarization conversion type modulator using periodically poled 8%MgO:cLT for the first time. A maximum efficiency of 93% was obtained, and the temperature acceptance bandwidth of the modulator was in close agreement with the calculated value.…”

“…We demonstrated a polarization conversion type modulator for violet light using periodically poled MgO doped LN (MgO:LN) having photorefractive damage resistance higher than that of non-doped LN. 14) Because the domain-inversion period required in the MgO:LN device is short (a few µm) and the wavelength acceptance bandwidth is narrow (<1 nm), fabrication is not easy and the phase-matching condition is critical. The birefringence of LT 15) is much smaller than that of LN; hence, it is expected that the required period will be larger and that fabrication will be easier in the modulator using LT.…”

“…1,[3][4][5] EO devices using these periodically poled structures have also been studied, and Bragg deflection and polarization conversion type modulators have been reported. [6][7][8][9][10][11][12][13][14] Polarization conversion type modulators have both high conversion efficiencies (theoretical value 100%) and wavelength bandwidths narrower than those of conventional transverse or longitudinal modulators. In addition, the electrode structure is simpler than that of conventional devices using comb electrodes, and the optical system is more compact than that of Bragg deflection type modulators.…”