High-power broad-area tapered amplifier with a monolithically integrated output focusing lens at 0.98-/spl mu/m wavelength

We have demonstrated a 0.98-/spl 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-/spl mu/m diode laser. The integrated semiconductor waveguide lens focused the amplifier output to a 8 /spl mu/m/spl times/3 /spl 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.<
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