A light-emitting element, comprising:
- a semiconductor substrate;
- a light emitting portion comprising an active layer sandwiched between a first cladding layer of a first conductivity type and a second cladding layer of a second conductivity type different from the first conductivity type;
- a first reflective portion between the semiconductor substrate and the light emitting portion for reflecting light emitted from the active layer, the first reflective portion comprising a plurality of pair layers each including a first semiconductor layer and a second semiconductor layer different from the first semiconductor layer;
- a current dispersion layer on an opposite side of the light emitting portion from the first reflective portion;
- an intermediate layer between the second cladding layer and the current dispersion layer, the intermediate layer comprising a semiconductor having a bandgap energy between a bandgap energy of a semiconductor comprising the second cladding layer and a bandgap energy of a semiconductor comprising the current dispersion layer;
- and
- a second reflective portion between the first reflective portion and the semiconductor substrate, the second reflective portion comprising a plurality of pair layers each including a third semiconductor layer and a fourth semiconductor layer different from the third semiconductor layer,
- wherein the first semiconductor layer has a thickness TA1 defined by a formula (1) and the second semiconductor layer has a thickness TB1 defined by a formula (2), where λP represents a peak wavelength of the light emitted from the active layer, nA represents a refractive index of the first semiconductor layer, nB represents a refractive index of the second semiconductor layer, nIn represents a refractive index of the first cladding layer, where a principal surface of the second semiconductor layer is the incident plane of light
- wherein the plurality of pair layers of the first reflective portion each comprise the first semiconductor layer and the second semiconductor layer with the thickness defined by the formula (1) and the formula (2), respectively, with limiting θ in a range of not less than 44 degrees and not more than 61 degrees,
- wherein a value of θ is different from each other among the plurality of pair layers of the first reflective portion,
- T
- A
-
-
- 1
- =
- λ
- p
- 4
-
- n
- A
-
- 1
- -
- (
- n
- In
-
- sin
-
-
- θ
- n
- A
- )
- 2
- Formula
-
-
- (
- 1
- )
- T
- B
-
-
- 1
- =
- λ
- p
- 4
-
- n
- B
-
- 1
- -
- (
- n
- In
-
- sin
-
-
- θ
- n
- B
- )
- 2
- Formula
-
-
- (
- 2
- )
- wherein the plurality of pair layers of the first reflective portion each comprise the first semiconductor layer having the thickness TA1 that is not less than 1.5 times of λP/4nA and the second semiconductor layer having the thickness TB1 that is not less than 1.5 times of λP/4nB,
- wherein the third semiconductor layer has a thickness TC defined by a formula (3) where λP2 is 870±30 nm and nC represents a refractive index of the third semiconductor layer, and
- wherein the fourth semiconductor layer has a thickness TD defined by a formula (4) where nD represents a refractive index of the fourth semiconductor layer
- T
- C
- =
- λ
- p
-
-
- 2
- 4
-
- n
- C
- Formula
-
-
- (
- 3
- )
- T
- D
- =
- λ
- p
-
-
- 2
- 4
-
- n
- D
- .
- Formula
-
-
- (
- 4
- )