Switchable multiple wavelength semiconductor laser

• US 5,200,969 A
• Filed: 10/18/1991
• Issued: 04/06/1993
• Est. Priority Date: 10/18/1991
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Paoli, Thomas L.
• Primary Examiner(s): Davie, James W.
• Application Number:
  US07/779,211
• Time in Patent Office: 536 Days
• Field of Search: 372/46, 372/45, 372/50, 372/26, 372/20
• US Class Current: 372/50.1
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01S 3/0809 Two-wavelenghth emission
• CPC Class Codes: H01S 3/1061 using a variable absorption device
• CPC Class Codes: H01S 5/0208 Semi-insulating substrates
• CPC Class Codes: H01S 5/0422 with n- and p-contacts on the same side of the active layer
• CPC Class Codes: H01S 5/0601 comprising an absorbing region H01S5/0604, H01S5/0607, H01S5/0615 and H01S5/065 take precedence; bistable laser devices in general G02F3/026
• CPC Class Codes: H01S 5/0622 Controlling the frequency of the radiation
• CPC Class Codes: H01S 5/06255 Controlling the frequency of the radiation
• CPC Class Codes: H01S 5/34 comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers H01S5/36 takes precedence
• CPC Class Codes: H01S 5/3412 quantum box or quantum dash
• CPC Class Codes: H01S 5/3418 using transitions from higher quantum levels
• CPC Class Codes: H01S 5/343 in AIIIBV compounds, e.g. AlGaAs-laser , InP-based laser
• CPC Class Codes: H01S 5/3432 the whole junction comprising only (AI)GaAs
• CPC Class Codes: H01S 5/4043 with vertically stacked active layers
• CPC Class Codes: H01S 5/4087 emitting more than one wavelength

Abstract

A multiple wavelength semiconductor laser includes a plurality of layers, one or more of said layers comprising a carrier confinement (multiple quantum well) active region of the type wherein at least two confining regions (quantum wells) contained in the active region are formed such that one quantum level of a first region (quantum well) is at the same energy level as a different quantum level of a second region (quantum well). This alignment of the quantum levels between two confinement regions (quantum wells) results in the recombination of carriers from one region augmenting the recombination of carriers from the other region, the net effect being an output intensity at both shorter and longer wavelengths of operation more nearly equal than heretofore available. Appropriate placement of the regions within the laser waveguide also facilitates a matching of the output intensity profile with a desired output mode, e.g., the fundamental mode TE00.

Claims

1. A solid state semiconductor laser switchable between at least two different output wavelengths, comprising:

a laser body of the type including a plurality of contiguous layers of semiconductor material, located in an optical path, at least first and second portions of said layers of the type providing carrier quantization in at least one dimension, wherein said first and second portions are formed such that one quantum level of said first portion is at the same energy level as a different quantum level of said second portion;

means for providing gain in said optical path when an electrical bias is applied thereto;

means for providing loss in said optical path when an electrical bias is applied thereto to thereby limit the output of said laser to a first wavelength which corresponds to an energy level of said first portion which is not found in said second portion when a first electrical bias is applied thereto, and to thereby limit the output of said laser to a second wavelength different than said first wavelength which corresponds to an energy level found in both said first and second portions when a second electrical bias, different than said first electrical bias, is applied thereto.

2. A solid state semiconductor laser switchable between at least two different output wavelengths, comprising:

a laser body of the type including a plurality of contiguous layers of semiconductor material, located in an optical path, at least a first and second portions of said layers of the type providing carrier quantization in at least one dimension, wherein said first and second portions thereof are formed such that one quantum level of said first portion is at the same energy level as a different quantum level of said second portion;

means for providing gain in said optical path when an electrical bias is applied thereto;

first loss means for providing loss in said optical path when an electrical bias is applied thereto to thereby limit the output of said laser to a first wavelength which corresponds to an energy level of said first portion which is not found in said second portion,

second loss means for providing loss in said optical path when an electrical bias is applied thereto to thereby limit the output of said laser to a second wavelength different than said first wavelength which corresponds to an energy level found in both said first and second portion.

3. The laser of claim 2, further including means for switching an electrical bias such that said bias is applied either to said first loss means or said second loss means, to thereby cause said laser to emit an output at either a first or a second wavelength.

4. The laser of claim 2, wherein said first loss means comprises a waveguide of a first width, and said second loss means comprises a waveguide of a second width different than said first width.

5. The laser of claim 2, wherein said first loss means comprises a waveguide of a first length, and said second loss means comprises a waveguide of a second length different than said first length.

6. The laser of claim 2, wherein said means for providing gain and said first loss means are coupled by an optical waveguide, and said means for providing gain and said second loss means are not coupled by an optical waveguide.