Abstract: A semiconductor laser element may include an n-type clad layer; an n-type waveguide layer adjacent to the n-type clad layer; an n-type carrier blocking layer adjacent to the n-type waveguide layer; an active layer; and a p-type clad layer adjacent to the active layer. The n-type clad layer may have a bandgap width greater than a bandgap width of the n-type waveguide layer. The n-type carrier blocking layer may have a bandgap width greater than or equal to bandgap widths of the first and second barrier layers. The p-type clad layer may have a bandgap width greater than the bandgap widths of the first and second barrier layers and the bandgap width of the n-type waveguide layer. The active layer may include a quantum well layer and barrier layers.

Abstract: A semiconductor laser element includes an active layer, an n-type carrier blocking layer arranged so as to be adjacent to the active layer and having a bandgap width that is equal to or greater than those of barrier layers, an n-type waveguide layer arranged on a side opposite to a side of the n-type carrier-blocking layer on which the active layer is arranged, so as to be adjacent to the n-type carrier blocking layer, an n-type clad layer arranged on a side opposite to a side of the n-type waveguide layer on which the active layer is arranged, so as to be adjacent to the n-type waveguide layer, and having a bandgap width that is greater than that of the n-type waveguide layer, and a p-type clad layer arranged on a side opposite to a side of the active layer on which the n-type carrier blocking layer is arranged, so as to be adjacent to the active layer, and having a bandgap width that is greater than those of the barrier layers and the n-type waveguide layer.

Abstract: A semiconductor device includes: a circuit board; a semiconductor chip mounted over the circuit board with a predetermined gap therebetween and electrically connected to the circuit board by a protruding electrode; a first resin material filled into the gap between the circuit board and the semiconductor chip; a second resin material that seals the semiconductor chip mounted over the circuit board; a first reflector which is formed on a surface of the circuit board on the semiconductor chip side and reflects a predetermined testing light; and a second reflector which is formed on a surface of the semiconductor chip on the circuit board side and reflects the predetermined testing light.

Abstract: A laser module includes a semiconductor laser element and a feedback optical component forming an external cavity with the semiconductor laser element. Even if a ratio of a current threshold of the laser module changing according to a polarized state of returned light from the feedback optical component to a current threshold of the semiconductor laser element is in an arbitrary range within a predetermined range, a total value of a relative intensity noise occurring between a first frequency determined according to a cavity length of the external cavity and at least equal to or more than a frequency band of using a laser light and a second frequency calculated by multiplying the first frequency by a predetermined number is equal to or more than ?40 dB.

Abstract: A semiconductor device includes: a circuit board; a semiconductor chip mounted over the circuit board with a predetermined gap therebetween and electrically connected to the circuit board by a protruding electrode; a first resin material filled into the gap between the circuit board and the semiconductor chip; a second resin material that seals the semiconductor chip mounted over the circuit board; a first reflector which is formed on a surface of the circuit board on the semiconductor chip side and reflects a predetermined testing light; and a second reflector which is formed on a surface of the semiconductor chip on the circuit board side and reflects the predetermined testing light.

Abstract: A laser module includes a semiconductor laser element and a feedback optical component forming an external cavity with the semiconductor laser element. Even if a ratio of a current threshold of the laser module changing according to a polarized state of returned light from the feedback optical component to a current threshold of the semiconductor laser element is in an arbitrary range within a predetermined range, a total value of a relative intensity noise occurring between a first frequency determined according to a cavity length of the external cavity and at least equal to or more than a frequency band of using a laser light and a second frequency calculated by multiplying the first frequency by a predetermined number is equal to or more than ?40 dB.