Surface emitting and receiving photonic device

Abstract

A surface-emitting laser, in which light is emitted vertically at one end from a 45°-angled facet, includes a second end having a perpendicular facet from which light is emitted horizontally, for monitoring.

Description

BACKGROUND OF THE INVENTION [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 512,189, filed Oct. 20, 2003, and of U.S. Provisional Application No. 60 / 578,289, filed Jun. 10, 2004, the disclosures of which are hereby incorporated herein by reference. [0002] The present invention relates, in general, to surface emitting and receiving photonic devices, and more particularly to improved surface emitting laser devices and methods for fabricating them. [0003] Semiconductor lasers typically are fabricated by growing the appropriate layered semiconductor material on a substrate through Metalorganic Chemical Vapor Deposition (MOCVD) or Molecular Beam Epitaxy (MBE) to form an active layer parallel to the substrate surface. The material is then processed with a variety of semiconductor processing tools to produce a laser optical cavity incorporating the active layer, and metallic contacts are attached to the semiconductor material. Finally, laser mirror facets ...

AI Technical Summary

Benefits of technology

[0008] In accordance with the present invention, improved surface emitting semiconductor lasers are provided in which light is emitted at an emitter end of an optical cavity in a direction vertical to the plane of the laser active layer, and in which light is emitted at a reflective region at the opposite end of the cavity in the plane of the active layer. This arrangement facilitates monitoring of laser operation without adversely affecting the light output. In accordance with one form of the invention, a reflection modification layer or stack is provided on the emitter end while in another form of the invention filter elements are provided within the laser cavity, to permit operation of the laser in an essentially single longitudinal mode. Furthermore, in accordance with the invention, surface and in-plane detectors are provided on the same substrate as the laser, and multiple laser cavities are positioned to enable the emission of multiple wavelengths at a common location.

Problems solved by technology

The resultant devices cannot be tested in full-wafer and as such suffer from the same deficiencies as cleaved facet devices.

Furthermore, they are incompatible with monolithic integration in view of the need for cleaving.

Chao, et al., IEEE Photonics Technology Letters, volume 7, pages 836-838, attempted to overcome these short-comings, however, by providing an interrupted waveguide structure, but the resultant device suffered from scatter at each end of the laser cavity.

Vertical Cavity Surface Emitting Lasers (VCSELs), have gained popularity over the past several years; however, VCSELs do not allow in-plane monolithic integration of multiple devices and only allow light to exit their surface mirror at perpendicular incidence.

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