Integrated optical polariser on LiNbO3:Ti channel waveguides using proton exchange

A design method of lithium niobate on insulator ridge waveguides without leakage loss

“…Electro-optic modulators are also fabricated [4] in SOI, but owing to its weak electro-optic effect [5], silicon is not suitable for such devices. On the other hand, lithium niobate (LN) offers excellent electro-optic, acousto-optic, and nonlinear optical properties [6], so LN has been applied to various active and passive devices, such as modulators [7], mode converters [8], polarizer [9], and lasers [10]. However, most of the reported waveguides were fabricated by using Ti in-diffusion or proton exchange [11].…”

Proton Exchange in Lithium Niobate and Lithium Tantalate Single Crystals: Regularities and Specific Features

“…The attractive advantages of PE are its technological simplicity, high process intensity, and the ability to manufacture some unique integrated optical elements (IOE) such as chirped grating lenses [36], planar TIPE lenses [37 to 421, planar double proton exchanged lenses (DPE [43]), polarisers [44,45], elements for second harmonic generation [34,46 to 501, ring resonators [51 to 521, and also devices with modulators [53 to 551, deflectors [56], interferometers [57 to 621, spectrum analysers [40], and others. PE in LiNbO, can be also used for manufacturing acoustic channel guides [63].…”

Characterisation of proton-exchange slab optical waveguides in x-cut LiNbO3

“…Recently, the annealing of the PE waveguides has shown that the refractive-index profile of the optical waveguide can be changed from a nearly step-index profile to a graded-index profile, the modification being dependent upon the annealing time, temperature and atmosphere in which the process is carried out [6,9]. Various passive devices (high efficiency beam deflectors [10], second harmonic generators [11], chirped grating lenses [12], planar lenses [13], polarisers [14,15]) and active devices (optical frequency translators [16], Mach-Zehnder interferometers [17], acousto-optic deflectors [18,19]) have been demonstrated on different cuts of LiNbO 3 using the above techniques. Another advantage of proton-exchange waveguides in LiNbO 3 is that they have been found to be more resistant than titanium diffused waveguides to optical damage [20].…”