Light emitting device, manufacturing method thereof, and optical transceiver

• US 9,052,449 B2
• Filed: 11/24/2013
• Issued: 06/09/2015
• Est. Priority Date: 02/25/2013
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Sagawa, Misuzu, Oda, Katsuya, Tani, Kazuki
• Primary Examiner(s): Matthews, Colleen A
• Assistant Examiner(s): FORDE, DELMA ROSA
• Application Number:
  US14/088,422
• Publication Number:
  US 20140241734A1
• Time in Patent Office: 562 Days
• Field of Search: 372/43.01, 372/50.1, 257/80, 257/81, 257/98, 438 24- 26
• US Class Current: 1/1
• CPC Class Codes: G02B 6/12004 Combinations of two or more optical elements
• CPC Class Codes: G02B 6/1223 high refractive index type, i.e. high-contrast waveguides
• CPC Class Codes: G02B 6/1228 Tapered waveguides, e.g. integrated spot-size transformers for coupling with fibres G02B6/305
• CPC Class Codes: G02B 6/131 by using epitaxial growth epitaxial growth for semiconductors H01L21/02365
• CPC Class Codes: H01S 5/021 Silicon based substrates
• CPC Class Codes: H01S 5/026 Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers stabilisation of output H01S5/06
• CPC Class Codes: H01S 5/1014 Tapered waveguide, e.g. spotsize converter H01S5/1064 takes precedence
• CPC Class Codes: H01S 5/1032 Coupling to elements comprising an optical axis that is not aligned with the optical axis of the active region
• CPC Class Codes: H01S 5/141 using a wavelength selective device, e.g. a grating or etalon H01S5/146 takes precedence

Abstract

The light emitting device includes an active layer formed on a semiconductor substrate for emitting light, a semiconductor layer of a first conductivity type electrically connected to one end of the active layer, a semiconductor layer of a second conductivity type electrically connected to the other end of the active layer, first and second electrodes, a feedback mechanism for laser oscillation, and a waveguide for guiding the light emitted from the active layer, in which the active layer is made of a semiconductor having an affinity with a silicon CMOS process, and the semiconductor layer of the first conductivity type and the semiconductor layer of the second conductivity type, and the waveguide are each made of silicon as a part of the semiconductor substrate.

Claims

1. A light emitting device, comprising:

an active layer, formed on a semiconductor substrate, for emitting light, the active layer including;

a central region, and

a mode conversion region that tapers, in thickness and width, along the optical axis;

a semiconductor layer of a first conductivity type electrically connected to one end of the active layer;

a semiconductor layer of a second conductivity type electrically connected to the other end of the active layer;

first and second electrodes;

a feedback mechanism for laser oscillation; and

a waveguide for guiding the light emitted from the active layer,

wherein the active layer is made of a semiconductor having an affinity with a silicon CMOS process,

wherein the semiconductor layer of the first conductivity type, the semiconductor layer of the conductivity type, and the waveguide are each made of silicon as a part of the semiconductor substrate, and

wherein the mode conversion region couples the emitted light to the waveguide to minimize optical loss.

2. The light emitting device according to claim 1, wherein the waveguide is adjacent to the active layer in such a manner as to be optically coupled to the active layer.

3. The light emitting device according to claim 1, wherein the semiconductor substrate is a substrate made of silicon, a silicon dioxide, and silicon.

4. The light emitting device according to claim 3, wherein silicon has the largest refractive index among the materials composing the waveguide.

5. The light emitting device according to claim 2, wherein the mode conversion region of the active layer becomes thinner in film thickness as approaching the waveguide along the optical axis.

6. The light emitting device according to claim 2, wherein the mode conversion region of the active layer becomes narrower as approaching the waveguide along the optical axis.

7. The light emitting device according to claim 5, wherein an interface between the active layer and the semiconductor substrate and an interface on a side opposite to the active layer and the semiconductor substrate are approximately parallel to each other.

8. The light emitting device according to claim 1, wherein the active layer is composed of either germanium or silicon/germanium.

9. The light emitting device according to claim 1, wherein the mode conversion region tapers to a point proximate to the waveguide.

10. The light emitting device according to claim 1, wherein the feedback mechanism includes Bragg reflectors.