Abstract: An integrated optical isolator arrangement is described that is capable of isolating an input optical signal and coupling a pump signal. The coupler includes a pair of lenses with an isolator disposed therebetween. The isolator is sandwiched between a splitter/filter and a wavelength selective device. An end face of each lens has an input and an output port for receiving and transmitting optical signals. The splitter/filter is selected to transmit some of the input signal on a first input port and to reflect the remaining untransmitted portion of the input optical signal to a first output port proximate to the first input port. The wavelength selective device allows the input signal from the first input port to pass through it to a second output port, and in addition, reflects a pump signal transmitted on the second input port to the second output port for combination with the input optical signal.

Abstract: A semiconductor laser device according to the present invention comprises a GaAs substrate of a first conductivity type, a cladding layer of the first conductivity type formed on one main surface of the substrate, an active layer having a quantum well structure in which a tensile strain quantum well layer and a quantum barrier layer which are formed on the cladding layer of the first conductivity type are alternately laminated, and a cladding layer of a second conductivity type formed on the active layer. The one main surface of the substrate is a surface misoriented by 9.degree. to 17.degree. from a {100} plane of the substrate in a <011> direction, and the cavity length is not less than 150 .mu.m nor more than 300 .mu.m.