Abstract: A laser device is provided. The laser device includes a stack of epitaxial layers, a first conductive layer, an intermediate layer, and a first electrode. The stack of epitaxial layers has a central region and an edge region. The stack of epitaxial layers includes a first reflective structure, an active region disposed on the first reflective structure, a second reflective structure disposed on the active region. The first conductive layer disposes on the stack of epitaxial layers and covers the central region and at least a part of the edge region. The intermediate layer has a first opening that corresponding to the central region of the stack of epitaxial layers, wherein the intermediate layer comprises insulating material or metal. The first electrode disposes on the first conductive layer.

Abstract: A parallel hybrid circuit comprising a transformer, a first matching resistor, a second matching resistor and an echo cancelling circuit. The transformer comprises: a first side, comprising a transmitting coil group and a receiving coil group, wherein the transmitting coil group comprises at least one transmitting coil, wherein the receiving coil group comprises at least one receiving coil; a second side comprising at least one transceiving coil; wherein the transformer receives a transmitting signal and couples the transmitting signal from the first side to the second side via a first turn ratio, and receives a receiving signal from the transceiving line and couples the receiving signal from the second side to the first side via a second turn ratio. The first, second matching resistors are coupled with the transformer in parallel. The echo cancelling circuit is coupled between the transmitting line and the receiving line.

Abstract: A parallel hybrid circuit comprising a transformer, a first matching resistor, a second matching resistor and an echo cancelling circuit. The transformer comprises: a first side, comprising a transmitting coil group and a receiving coil group, wherein the transmitting coil group comprises at least one transmitting coil, wherein the receiving coil group comprises at least one receiving coil; a second side comprising at least one transceiving coil; wherein the transformer receives a transmitting signal and couples the transmitting signal from the first side to the second side via a first turn ratio, and receives a receiving signal from the transceiving line and couples the receiving signal from the second side to the first side via a second turn ratio. The first, second matching resistors are coupled with the transformer in parallel. The echo cancelling circuit is coupled between the transmitting line and the receiving line.