Process for making integrated laser/modulators

• US 6,172,999 B1
• Filed: 11/19/1999
• Issued: 01/09/2001
• Est. Priority Date: 12/30/1993
• Status: Expired due to Term

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Johnston, Wilbur Dexter Jr.
• Primary Examiner(s): DAVIE, JAMES W
• Application Number:
  US09/442,738
• Time in Patent Office: 417 Days
• Field of Search: 372/26, 372/50, 372/20, 372/49, 372/96
• US Class Current: 372/50.1
• CPC Class Codes: H01S 5/0064 Anti-reflection components, e.g. optical isolators
• CPC Class Codes: H01S 5/0265 Intensity modulators intra-cavity modulators H01S5/0625
• CPC Class Codes: H01S 5/028 Coatings ; Treatment of the laser facets, e.g. etching, passivation layers or reflecting layers
• CPC Class Codes: H01S 5/1014 Tapered waveguide, e.g. spotsize converter H01S5/1064 takes precedence
• CPC Class Codes: H01S 5/12 the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers comprising a photonic bandgap structure H01S5/11; surface-emitting lasers H01S5/18
• CPC Class Codes: H01S 5/125 Distributed Bragg reflector [DBR] lasers

Abstract

An integrated laser/modulator (“ILM”) operating with reduced chirping is formed on a single semiconductor substrate. A reduction in chirping and any resultant wavelength dispersion is realized by precisely controlling the length of a window region incorporated in the ILM in order to isolate the ILM'"'"'s active regions from any residual reflections.

Claims

1. A semiconductor laser and modulator integrated on a first side of a semiconductor opposite a single semiconductor foundation substrate side of said semiconductor, operating with reduced wavelength chirping, comprising:

semiconductor laser means for producing laser light deposited on said first side;

wavelength-selective grating means for selecting a specific wavelength of said laser light deposited on said first side;

semiconductor modulating means having a determinable width for modulating said selected laser light deposited on said first side; and

means for isolating said selected and modulated wavelength of light from said laser and modulating means, said isolating means further comprising a window region having an optimum length to permit tolerable reflectivity, said window region having a width wider than that of said modulating means, and an anti-reflective coating disposed on an end section of said isolating means;

said laser means, modulating means, wavelength-selective grating means and isolating means all disposed on said first side to form an integrated semiconductor circuit.

2. The semiconductor laser and modulator of claim 1 wherein said optimum length is formed by placement of a photolithographic V-shaped trench on said foundation substrate side, said optimum length controlled to a tolerance of +/−

10 microns by said placement.

3. The semiconductor laser and modulator of claim 2 wherein said wavelength-selective grating means comprises a distributed Bragg reflective grating.

4. The semiconductor laser and modulator of claim 2 wherein said wavelength-selective grating means comprises a distributed feedback grating.

5. The semiconductor laser and modulator of claim 3 or 4 wherein said window region comprises InP.

6. The semiconductor laser and modulator of claims 3 or 4 wherein said isolating means has an optimum length between 30 and 50 microns measured from said modulating means to said end section.

7. The semiconductor laser and modulator of claim 3 or 4 wherein said single foundation substrate side comprises InP.

8. The semiconductor laser and modulator of claim 3 or 4 wherein said first side is an n side of said semiconductor.

9. The semiconductor laser and modulator of claim 3 or 4 wherein said first side is a p side of said semiconductor.

10. The semiconductor laser and modulator of claim 3 or 4 wherein said modulating means comprises a biased p-n junction driven by a voltage source.

11. The semiconductor laser and modulator of claim 10 wherein said modulating means comprises a reverse biased p-n junction driven by said voltage source.