Surface emitting semiconductor laser

• US 4,949,350 A
• Filed: 07/17/1989
• Issued: 08/14/1990
• Est. Priority Date: 07/17/1989
• Status: Expired due to Term

• Current Assignee: American Telephone & Telegraph Company (AT&T, Inc.), Agere Systems Incorporated (Broadcom, Inc.)
• Original Assignee: Bell Communications Research, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Scherer, Axel, Jewell, Jack L.
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Epps, Georgia Y.
• Application Number:
  US07/380,996
• Time in Patent Office: 393 Days
• Field of Search: 372/45, 372/43, 372/96, 372/46, 357/4, 357/17
• US Class Current: 372/45.01
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01S 5/18305 with emission through the substrate, i.e. bottom emission
• 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 5/3054 p-doping
• CPC Class Codes: H01S 5/3432 the whole junction comprising only (AI)GaAs

Abstract

A vertical-cavity surface emitting laser and method of making in which a III-V heterostructure is epitaxially grown to include a quantum well active region between two interference mirrors separated by an emitting wavelength of the quantum well region. A small pillar of this heterostructure is etched by chemically assisted xenon ion beam itching. Prior to etching, a top metal contact is deposited on the epitaxial semiconductor. Light is emitted through the substrate having a bandgap larger than that of the quantum well region.

Claims

1. A vertical-cavity, surface emitting laser, comprising:

a crystalline substrate;

a lower multiple layer interference mirror epitaxially formed on said substrate, said layers being arranged in a vertical direction;

an active region comprising at least one quantum well layer epitaxially formed on said lower mirror and lasing a predetermined wavelength λ

;

an upper multiple layer interference mirror epitaxially formed on said active region;

a lower and an upper spacer region interposed between said active region and respective ones of said mirrors and epitaxial therewith to provide a vertical optical cavity between opposing faces of said mirrors separated by an optical distance L of a predetermined relationship to said wavelength λ

; and

wherein at least said active region, said upper spacer region and said upper mirror are formed into a vertical waveguiding region having a substantially constant cross-section area A and an effective dielectric constant n below said upper mirror;

said laser further comprising;

a medium laterally substantially surrounding said waveguiding region and having a dielectric constant less than said effective dielectric constant n; and

two electrical contact regions, one of said electrical contact regions being electrically connected to said waveguiding region above said active region, electrical power applied to said contact regions causing said laser to lase at said wavelength λ

with a loss per pass of S;

wherein a waveguiding confinement factor ##EQU3## has a value approximately equal to or greater than 17.

2. A laser as recited in claim 1, wherein said waveguiding confinement factor has a value approximately equal to or greater than 40.

3. A laser as recited in claim 1, wherein a first one of said mirrors is doped p-type, wherein said multiple layers of said first mirror comprise alternating first and second layers having respective first and second refractive indices, said first and second layers being vertically arranged on an optical period of λ

/2, said first mirror further comprising superlattices of different materials having refractive indices different therebetween and interposed between said first and second layers.

4. A laser as recited in claim 3, wherein said mirror is said upper mirror and wherein said one electrical contact region comprises a metallic layer formed above said upper mirror.

5. A vertical-cavity, surface emitting laser, comprising:

a crystalline substrate;

a lower multiple layer interference mirror epitaxially formed on said substrate;

an active region comprising at least one quantum well layer epitaxially formed on said lower mirror and lasing at a predetermined wavelength λ

;

an upper multiple layer interference mirror epitaxially formed on said active region;

a lower and an upper spacer region interposed between said active region and respective ones of said mirrors and epitaxial therewith to provide an optical cavity between opposing faces of said mirrors separated by an optical distance L of a predetermined relationship to said wavelength; and

wherein said active region, said upper spacer region and said upper mirror are formed in a mesa structure rising above said substrate and having a cross-sectional area A, said mesa structure having an effective dielectric constant n below said upper mirror;

said laser further comprising at least two electrical contacts, one of said electrical contacts being attached to said mesa structure above said active region, said contacts causing said laser to lase at said wavelength λ

with a loss per pass of S;

wherein a waveguiding confinement factor ##EQU4## has a value approximately equal to or greater than 17.

6. A laser as recited in claim 5, wherein said value of W is approximately equal to or greater than 40.

7. A laser as recited in claim 5 wherein said mesa structure includes said lower mirror and said lower spacer region.

8. A laser as recited in claim 7, wherein said mirrors, said active region and said spacer regions comprise III-V semiconductor materials.

9. A laser as recited in claim 8, wherein said active region and said spacer regions of said mesa structure are bounded on all lateral sides thereof within an optical distance 10·

λ

by a medium of other than III-V semiconducting material.

10. A laser as recited in claim 5, wherein said one of said electrical contacts comprises a metallic layer formed above said upper mirror and having a cross-section of at least A.

11. A laser as recited in claim 10, wherein said at least one quantum well layer consists of one quantum well layer.

12. A laser as recited in claim 10, wherein said at least one quantum well layer consists of three quantum well layers.

13. A vertical-cavity, surface emitting laser, comprising:

a crystalline substrate;

a lower multiple layer interference mirror epitaxially formed on said substrate;

an active region comprising at least one quantum well layer epitaxially formed on said lower mirror and lasing at a predetermined wavelength λ

;

an upper multiple layer interference mirror epitaxially formed on said active region;

a lower and an upper spacer region interposed between said active region and respective ones of said mirrors and epitaxial therewith to provide an optical cavity between opposing faces of said mirrors separated by an optical distance of a predetermined relationship to said wavelength; and

wherein said active region, said upper spacer region and said upper mirror are formed in a mesa structure rising above said substrate and having a substantially uniform cross-sectional area less than a cross-sectional area of said substrate;

said laser further comprising at least two electrical contacts, one of said electrical contacts being attached to said mesa structure above said active region;

wherein said mirrors, said active region and said spacer regions comprise III-V semiconductor materials; and

wherein said active region and said spacer regions of said mesa structure are bounded on all lateral sides thereof within an optical distance 10·

λ

by a medium of other than III-V semiconducting material.