Semiconductor optical amplifier array device

A semiconductor optical amplifier array device comprising:

• a substrate;
• and
• a plurality of semiconductor optical amplifiers formed on the substrate, each of the semiconductor optical amplifiers including
• two active regions,
• a passive portion, and
• two input-output ports optically connected to the active regions respectively and disposed on same facet of the semiconductor optical amplifier array device, wherein
• the plurality of semiconductor optical amplifiers include
• a first semiconductor optical amplifier in which length of the active region is equal to a first length, and
• a second semiconductor optical amplifier in which length of the active region is equal to a second length that is different from the first length,
• the two active regions are parallel to each other and are optically connected to each other via the passive portion,
• the passive portion includes a folded portion being formed of a high-mesa passive waveguide that is practically folded at an angle of 180°,
• a trench groove is formed to electrically separate some part of the first semiconductor optical amplifier from some part of the second optical amplifier,
• the first semiconductor optical amplifier and the second optical amplifier are driven in an independent manner, and
• lengths of the two active regions are adjusted by changing a position of the passive portion in a direction of extension of the two active regions.