The invention disclosed here teaches methods to fabricate and utilize a non-dispersive holographic wavelength blocker. When a direction of yawing motion created by LDP control is opposite to a direction of yawing motion created by VDC control, the cooperative control section puts a higher priority on VDC control rather than LDP control. The indicators are set to a first state when a scan is performed, and remain in the first state up until the time the host feedback is received.