HIGH-POWER BROAD-AREA TAPERED AMPLIFIER WITH A MONOLITHICALLY INTEGRATED OUTPUT FOCUSING LENS AT 0.98-MU-M WAVELENGTH

We have demonstrated a 0.98-mu m wavelength tapered broad-area amplifier with a monolithically integrated aspherical waveguide lens, CW output exceeding 1 W from the amplifier-lens chip was measured with 10 mW input from a 0.98 mu m diode laser, The integrated semiconductor waveguide lens focused the amplifier output to a 8 mu m x 3 mu m spot, which was measured at output power up to about 0.5 W, corresponding to 2.5 times the diffraction limit, The beam propagation method was used to model the integrated amplifier-lens chip, and the calculated focal distances agree with the experiment to within 5%. The integrated lens may be used for output coupling to a single mode fiber with the requirement that the focal point should be positioned on the output facet. Based on BPM simulation, however, the focal point position becomes uncritical if a single mode output waveguide is integrated, Our results indicate that the waveguiding lens is a useful component for the design of high-power photonic integrated circuits.