  Coherent homodyne detection requires a precise matching of emission
wavelengths between transmitter and local oscillator at the receiver.
Injection-locking can provide all-optical synchronization of the emission
frequencies, even under wavelength-swept emission. By adapting the sweep
parameters to the conditions in the optical fiber plant, transmission
impairments can be mitigated. In this regard I experimentally demonstrate that
a wavelength-hopping yet locked transceiver pair, which builds on conceptually
simple externally modulated laser technology, features a much higher robustness
to reflection crosstalk. The reception penalty due to distortions arising at a
Fresnel reflection in the transmission path can be reduced by >90% at a low
optical signal-to-reflection ratio of ~0 dB.
