For the first time, we believe, the integration of a waveguide lens and a photodetector array in GaAs for operation at a 1.3-µm wavelength is reported. The waveguide lens is a newly devised curved hybrid Fresnel/Bragg chirp grating lens fabricated by the ion-million technique. Desirable performance characteristics, including high throughput efficiency, freedom from coma (up to ±4 deg off axis), and a near-diffraction-limited focal-spot size, have been demonstrated with this curved hybrid lens. The 10-element photodetector array of the InGaAs photoconducting type shows a measured gain-bandwidth product that is higher than 1 GHz at high frequency, while at a lower frequency the gain is in the range of several thousands. The curved-hybrid-lens-photodetector array combination realized in the GaAs 5 × 13 mm2 in size has produced a well-resolved element spacing of 10 µm with cross talk that is lower than -14 dB. This lens-photodetector array combination constitutes a basc structure for the realization of monolit ic acousto-optic and electro-optic circuits such as integrated-optic rf spectrum analyzers and multiport switches.
© 1992 Optical Society of America
T.Q. Vu, C. S. Tsai, and Y. C. Kao, "Integration of a curved hybrid waveguide lens and photodetector array in a GaAs waveguide," Appl. Opt. 31, 5246-5254 (1992)