US 6,611,539 B2 · Wavelength-tunable vertical cavity surface emitting laser and method of making same

Abstract

A wavelength tunable semiconductor vertical cavity surface emitting laser which includes at least one active element including an active layer generating an optical gain by injection of a current, and at least one phase control element, and mirrors. The phase control element contains a modulator exhibiting a strong narrow optical absorption peak on a short wavelength side from the wavelength of the laser generation. The wavelength control is realized by using a position-dependent electro-optical effect. If a reverse bias is applied, the absorption maximum is shifted to longer wavelengths due to the Stark effect. If a forward bias is applied, a current is injected and results in the bleaching and reduction of the peak absorption. In both cases a strong modulation of the refractive index in the phase control element occurs. The effect tunes the wavelength of the cavity mode, and the sign and the value of the wavelength shift are defined by the position of the modulator. Two phase control cascades can be implemented into the laser, one of which shifts the wavelength of the emitted light to larger values, and the other shifts the wavelength of the emitted light to smaller values. A power equalizing element can be used in such laser allowing either to maintain the constant output power at different emission wavelengths or to realize an independent frequency and amplitude modulation. A photodetecting element can be implemented in the laser allowing calibration of the laser for all operations.

Claims54

Dependent claims

A wavelength tunable semiconductor vertical cavity surface emitting laser comprising:

a) a substrate;
b) a bottom mirror formed by a Bragg reflector region above the substrate;
c) an active element that includes:
i) a light generating layer that emits light when exposed to an injection current when a forward bias is applied,
ii) a first n-doped current spreading region above the substrate and below the light generating layer,
iii) a first p-doped current spreading region above the light generating layer,
iv) a first current aperture placed between each neighboring region, and
v) an active element bias control device between the n-doped current spreading region and the p-doped current spreading region such that current can be injected into the light generating layer to generate light;
d) a phase control element that includes:
i) a modulating layer located above the first p-doped current spreading region that modulates the wavelength of light when exposed either to an electric field when a reverse bias is applied, or to an injection current when a forward bias is applied due to position-dependent electro-optical effect,
ii) a second n-doped current spreading region above the modulating layer,
iii) a second current aperture placed between each neighboring region, and
iv) a phase control element bias control device between the second n-doped current spreading region and the first p-doped current spreading region such that an electrical field can be created that causes the modulating layer to modulate the wavelength of light;
and
e) a top mirror formed by a Bragg reflector region above the second n-doped current spreading region.

12 more elements

A wavelength tunable semiconductor vertical cavity surface emitting laser comprising:

a) a substrate;
b) a bottom mirror formed by a Bragg reflector region above the substrate;
c) an active element that includes:
i) a light generating layer that emits light when a current is injected,
ii) a first n-doped current spreading region above the substrate and below the light generating layer,
iii) a first p-doped current spreading region above the light generating layer,
iv) a first current aperture placed between each neighboring region, and
v) an active element bias control device between the n-doped current spreading region and the p-doped current spreading region such that current can be injected into the light generating layer to generate light;
d) a first phase control element that includes:
i) a first modulating layer located above the first p-doped current spreading region that modulates the wavelength of light when exposed either to an electric field when a reverse bias is applied, or to an injection current when a forward bias is applied due to position-dependent electro-optical effect,
ii) a second n-doped current spreading region above the modulating layer,
iii) a second current aperture placed between each neighboring region, and
iv) a first phase control element bias control device between the second n-doped current spreading region and the first p-doped current spreading region such that an electrical field can be created that causes the first modulating layer to modulate the wavelength of light;
and
c) a second phase control element that includes:
i) a second modulating layer that is located above the second n-doped current spreading region that modulates the wavelength of light when exposed either to an electric field when a reverse bias is applied, or to an injection current when a forward bias is applied due to position-dependent electro-optical effect, wherein the second modulating layer is set to produce a shift of the wavelength of the emitted light into the opposite direction of the spectrum with respect to the first modulating layer,
ii) a second p-doped current spreading region above the modulating layer,
iii) a third current aperture placed between each neighboring region, and
iv) a second phase control element bias control device between the second n-doped current spreading region and the second p-doped current spreading region such that an electrical field can be created that causes the second modulating layer to modulate the wavelength of light;
and
f) a top mirror formed by a Bragg reflector region above the second p-doped current spreading region.

18 more elements

Dependencies are inferred from the claim text.

Wavelength-tunable vertical cavity surface emitting laser and method of making same

Life of this patent

Wavelength-tunable vertical cavity surface emitting laser and method of making same

Life of this patent

Abstract

Claims54