  Steering is a type of quantum nonlocality that exhibits an inherent asymmetry
between two observers. In a nondegenerate three-level laser coupled to a
two-mode squeezed vacuum reservoir, we examine, under realistic experimental
conditions, the Gaussian steering of two laser modes, $\mathcal{A}$ and
$\mathcal{B}$, generated within the cascade transitions, respectively. We find
that the $\mathcal{A}\rightarrow \mathcal{B}$ steerability is always higher
than that from $\mathcal{B}\rightarrow \mathcal{A}$; in addition, the steering
asymmetry cannot exceed $\ln 2$, which implies that the state
$\hat{\varrho}_{\mathcal{AB}}$ never diverges to an extremal asymmetry state.
We show how squeezed noise can play a constructive role in realizing one-way
steering. As the main result, we demonstrate that the state
$\hat{\varrho}_{\mathcal{AB}}$ can exhibit one-way steering solely from
$\mathcal{A}\rightarrow \mathcal{B}$, which we show to emerge as a consequence
of the fact that the intensity difference of the modes $\mathcal{A}$ and
$\mathcal{B}$ is verified to remain always positive, irrespective of the
physical and environmental parameters of $\hat{\varrho}_{\mathcal{AB}}$. The
generated unidirectional one-way steering may provide a useful resource for the
distribution of the trust in future asymmetric quantum information tasks.
