Matthew J. Kawas

Integrated optical device with second-harmonic generator, electrooptic lens, and electrooptic scanner in LiTaO/sub 3/

This paper reports the first demonstration of an integrated optical device in z-cut LiTaO/sub 3/ that contains the following three functional parts: a quasiphase-matched second-harmonic generation (SHG) grating, an electrooptic (EO) lens, and an electrooptic scanner. The SHG device consists of channel waveguides passing through periodic domain-inverted gratings. The frequency of the input infrared (IR) light at 864 nm was doubled into blue light at 432 nm. A stack of EO lenses was used to collimate the light from the channel waveguide. The measured beam size at the output facet for various applied voltages to the lenses agreed with simulation. After collimation, light passes through an EO scanner that controls the angle of the output beam. A scanning sensitivity of 17 mrad/kV was measured for the scanner, compared to the calculated value of 15 mrad/kV.

Integrated quasi-phase-matched second-harmonic generator and electrooptic scanner on LiTaO 3 single crystals

We report the first integrated quasi-phase-matched second-harmonic generator and electrooptic scanner on ferroelectric Z-cut LiTaO/sub 3/. The quasi-phase-matched second-harmonic generation device frequency doubles the infrared light at 829.7 nm into blue at 414.85 nm with a bulk conversion efficiency of 0.52%/W-cm. The blue light generated in the bulk then passes through an electrooptic scanner, consisting of a series of lithographically defined triangular-shaped domain-inverted regions extending through the thickness of the crystal. A deflection of 12 mrad/kv for the output blue light and 7.4 mrad/kv for the infrared light was observed at the scanner output.

Shape-optimized electrooptic beam scanners: experiment

A new horn-shaped electrooptic scanner is described with significantly improved scanning sensitivity over rectangular-shaped devices. In the new device, the shape of the scanner is chosen to follow the trajectory of the beam. An example design is described that exhibits a factor of two larger scanning sensitivity than a rectangular device with comparable maximum scanning angle. Beam propagation simulations and measurements on an experimental device verify the scanner performance.

Electrooptic lens stacks on LiTaO/sub 3/ by domain inversion

The design and analysis of one-dimensional (1-D) electrooptic lens stacks is presented. Experimental results of a seven-element stack fabricated on Z-cut LiTaO/sub 3/ substrates using domain inversion support the analysis. The optical focusing power of these bulk stacks is shown to be voltage-controlled.

Electrooptic wafer beam deflector in LiTaO/sub 3/

A novel electrooptic beam deflector is reported based on ferroelectric domain inversion extending through the thickness of a Z-cut LiTaO/sub 3/ wafer. The selective domain inversion is achieved by electric-field poling assisted by proton exchange, rather than proton exchange followed by rapid thermal annealing. The deflection sensitivity of the device was measured to be 5.0 mrad/KV. This is 93% of the theoretical value for this geometry, and a significant improvement over the value of 80% of theoretical previously reported for a waveguide deflector. This improvement is attributed to the new domain inversion process. No degradation of deflection sensitivity is observed up to the frequency of 300 KHz, which is then limited by the response time of detectors.

Electro-optic wafer beam deflector in LiTaO3

A novel electro-optic beam deflector is reported based on ferroelectric domain inversion extending through the thickness of a Z-cut LiTaO3 wafer. The selective domain inversion is achieved by electric-field poling assisted by proton exchange, rather than proton exchange followed by rapid thermal annealing. The deflection sensitivity of the device was measured to be 5.0 mrad/KV. This is 93% of the theoretical value for this geometry, and a significant improvement over the value of 80% of theoretical previously reported for a waveguide deflector.

Ferroelectrics as a versatile solid state platform for integrated optics

Abstract A high speed electro-optic scanner is demonstrated on a ferroelectric LiTaO3 crystal. The scanner shows a deflection of 39.5 mrad/kV, 13 resolvable spots per kV, and shows no degradation of performance upto 10MHz of driving field. Integration of the scanner with quasi-phase-matched frequency doublers and lenses is discussed.

Fabrication and characterization of high-speed integrated electro-optic lens and scanner devices

We demonstrate two high-speed electro-optic devices: an integrated lens/scanner and a variable radius collimating lens stack fabricated on a single crystal of Z-cut LiTaO3. The lens and scanner components consist of lithographically defined domain-inverted regions extending through the thickness of the crystal. A lens power of 0.233 cm-1kV-1, a deflection angle of 12.68 mrad kV-1, and a scan rate of 225 kHz at 375 V were observed. The collimating lens stack is theoretically capable of collimating the output from 2 - 10 micron diameter channel waveguides.

Integration of electro-optic lenses and scanners on ferroelectric LiTaO3

Abstract An integrated electro-optic lens/scanner device was fabricated on ferroelectric LiTaO3 wafer. This was done using lithographically defined domain-inverted regions extending through the crystal thickness. A lens power of 0.233 cm−1kV−1 and a scanner deflection of 12.68 mrad−1 kV−1 was observed. We also demonstrate an electro-optic lens stack collimator which collimates an input beam focused to 5μm waist diameter at 2.3kV.