Waveguide Electrooptic Modulators

Performance Projection of Electro-Optical Modulators for Radio-Over-Fiber in 2 GHz Cryogenic Front-End Receivers

“…2, for photons incident at time at the position , the difference of induced phase shifts into each optical waveguide over an interaction length is given by [2] ( 1) where is the optical wavelength, the optical refractive index, the electro-optical coefficient, the optical-electrical mode field overlap integral, the inter-electrode gap and is the instantaneous longitudinal distribution of voltage along the electrode which, as usual, can also be represented by its frequency dependent complex amplitude by using Fourier decomposition, (2) where is the modulating frequency. Applying standard microwave transmission line theory [7] over the equivalent circuit of Fig.…”

“…Operation at cryogenic temperatures in conjunction with high temperature superconductors has proved the potential to increase performance in front-end receivers in this frequency band [1]. Using coplanar technology, Mach-Zehnder electro-optical modulators on (LNO) substrates have been successfully used to intensity modulate the radio-frequency signal into the optical carrier [2]; The most common configuration is traveling-wave (TW) modulators based on co-propagation of both waves. Cumulative phase shift acquired by the optical carrier over the interaction length is strongly dependent on the mismatch in propagating velocities and on the electrode loss, yielding a trade-off between usable bandwidth and maximum electrode length that in turns limits the maximum modulation efficiency for each given operation frequency.…”

GaAs based long-wavelength microring resonator optical switches utilising bias assisted carrier-injection induced refractive index change

“…Optical switches based on refractive index (RI) changes can be realized using various modulation mechanisms, such as electro-optic (EO) [2], acousto-optic [3], magneto-optic [3], thermo-optic (TO) [4], electro-absorption (EA) [5][6][7], and bias assisted carrier-injection (CI) effects [5,6]. Note that, guided-wave optical switches are usually made of Lithium-Niobate (LiNbO 3 ) which uses EO effect as the primary switching mechanism.…”

Development of new photonic devices based on barium titanate in silicon

“…The difference between both RF and optical signals gives us the theoretical EO bandwidth f assuming a RF lossless medium [73]:…”