This paper reports behavior of modal gain with current density for SQW and MQWs based GRIN InGaAlAs/InP lasing nano heterostructures. The calculations have been made in both TE and TM modes. The modal gain obtained for GRIN InGaAlAs/InP lasing nano heterostructures in TE mode is found larger than that in TM mode. Moreover, it has been reported that the modal gain increases as the number of quantum wells in the structure increases in both TE and TM modes. These structures are very useful in the optical fiber communication
systems due to minimum optical losses.