Selective regrowth of a wide-bandwidth 1.3 mum integrated lossless tap and optical preamplifier

• Published in: IEEE photonics technology letters 1993-07, Vol.5 (7), p.797-800
• Main Authors: Rideout, W, Schlafer, J, Abdalla, M, Eichen, E, Russell, W, Niland, W, Meland, E, Powazinik, W
• Format: Article
• Language: English
• ISSN: 1041-1135
• DOI: 10.1109/68.229810

The authors report the first monolithically integrated wide-bandwidth lossless tap-that is, an optical semiconductor amplifier followed by a colinear reverse-biased waveguiding photodetector with fiber-coupled input and output. The integration was achieved by using off-axis selective epitaxial growth of ridge waveguides on a patterned dielectric layer. The tilted facets produced by the off-axis growth, along with photodetector absorption, serve to reduce the effective facet reflectivity to -36 dB without any antireflection coating. By adjusting the length of the absorbing photodetector section, part or all of the amplified light may be absorbed, allowing the device to function respectively as a lossless tap or an optical preamplifier. A lossless tap with an electrical bandwidth of 7 GHz, a responsivity of 26 A/W, and a fiber-to-fiber gain of 3 dB is shown to have a receiver sensitivity of -22 dB at 3 Gb/s