Detector for photonic integrated transceivers

Abstract

An integrated light-emitting device has a laser section and a detector section. The laser section and the detector section have an active layer that is integrated along an in-line waveguide. The detector section also has a bulk layer adjacent to the active layer, where the bulk layer has a band gap energy lower than the band gap energy of the active layer. In one embodiment, the active layer is an multiple quantum well (MQW) layer, the waveguide has two quaternary layers, and the bulk layer is a bulk quaternary layer. The device, which has uncooled modes of operation for both transmitting and receiving, may be used as a transceiver in a ping-pong optical data link configuration. The device may also have a beam expander section, with the laser, detector, and beam expander sections inside a Fabry-Perot cavity, along the single in-line waveguide. In one embodiment having a 1.3 .mu.m lasing wavelength, the addition of a 1.4 .mu.m bulk quaternary layer provides the detector with a broad spectral responsivity range extending 33 nm higher than the lasing wavelength of the device. This permits uncooled operation of the device with sufficient response even in the most severe temperature scenarios that would typically occur. The transmitter can provide 8 dBm inside a single mode fiber, and the beam expander relaxes the alignment tolerance, using a cleaved rather than a lensed single mode fiber.