VCSEL optimized for high speed data

• US 8,031,752 B1
• Filed: 12/19/2008
• Issued: 10/04/2011
• Est. Priority Date: 04/16/2007
• Status: Active Grant

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Finisar Corporation (II-VI Incorporated)
• Inventors: Johnson, Ralph H., Guenter, James K., Biard, James R.
• Primary Examiner(s): Nguyen; Dung T
• Application Number:
  US12/340,286
• Time in Patent Office: 1,019 Days
• Field of Search: 372/43.01, 372/45.01, 372/46.01, 372/50.1, 372/50.124
• US Class Current: 372/43.01
• CPC Class Codes: H01S 5/18311 using selective oxidation
• CPC Class Codes: H01S 5/18344 characterized by the mesa, e.g. dimensions or shape of the mesa
• CPC Class Codes: H01S 5/18358 containing spacer layers to adjust the phase of the light wave in the cavity
• CPC Class Codes: H01S 5/18361 Structure of the reflectors, e.g. hybrid mirrors
• CPC Class Codes: H01S 5/305 characterised by the doping materials used in the laser structure
• CPC Class Codes: H01S 5/3077 plane dependent doping
• CPC Class Codes: H01S 5/3211 characterised by special cladding layers, e.g. details on band-discontinuities

Abstract

A Vertical Cavity Surface Emitting Laser (VCSEL) is optimized for longer life of the VCSEL by controlling the distance of doped and undoped layers near an active region. In addition, the VCSEL optimized for reduced parasitic lateral current under an oxide of the VCSEL by forming a high Al confinement region and placing the oxide at a null in a standing optical wave. Further, the VCSEL is optimized to reduce resistance.

Claims

1. A Vertical Cavity Surface Emitting Laser optimized for reduced parasitic lateral current under an oxide of the Vertical Cavity Surface Emitting Laser, wherein non-radiative recombination occurs at an oxide semiconductor boundary according to a non-radiative lifetime, the Vertical Cavity Surface Emitting Laser comprising:

an active region including one or more quantum wells, wherein the active region comprises a high Al confinement region, the high Al being about >

80% or more;

an oxide layer comprising an aperture disposed near the active region, wherein vertically the center of the oxide layer is about ¾

wave optical thickness from the center of the quantum wells;

an intermediate region between the active region and the oxide layer, the intermediate region comprising a direct bandgap material with radiative lifetimes that are less than non-radiative lifetimes, and

a spacer region, the spacer region comprising an extra mirror period, wherein the extra mirror period comprises low Al and is configured to trap minority carriers to allow them to recombine radiatively in the intermediate region.

2. The Vertical Cavity Surface Emitting Laser of claim 1, further comprising:

a lower or upper mirror comprising AlAs as part of a Distributed Bragg Reflector stack; and

a thick AlAs cavity extension disposed at the lower mirror, and wherein the thick AlAs cavity extension act as an additional mirror layer, and wherein the AlAs cavity extension is periodically doped such that more heavily doped portions of the AlAs cavity extension occur at or near nulls of a standing electrical field.

3. The Vertical Cavity Surface Emitting Laser of claim 2, wherein the thick AlAs cavity extension is about one of 0.75, 1.25, 1.75, or 2.25 wavelengths thick.

4. The Vertical Cavity Surface Emitting Laser of claim 1, wherein the oxide layer is configured to be located at a null of a standing optical wave in the Vertical Cavity Surface Emitting Laser.

5. The Vertical Cavity Surface Emitting Laser of claim 1, wherein the oxide layer is thin and has a sharp point.

6. The Vertical Cavity Surface Emitting Laser of claim 5, wherein the oxide layer is constructed such that within 0.1 microns of the tip the oxide layer is about <

350 Angstroms and tapers to a thickness of at least 600 Angstroms at a distance from the aperture of about 2-4 microns from the aperture.

7. The Vertical Cavity Surface Emitting Laser of claim 6, wherein the oxide layer tapers to at least 1000 Angstroms at a distance from the aperture of about 2-4 microns from the aperture.

8. The Vertical Cavity Surface Emitting Laser of claim 1, wherein the intermediate region and the spacer region are the same region.