An external cavity laser apparatus and method wherein wavelength or channel selection
is carried independently from adjustment of external cavity optical path length.
The apparatus comprises a wavelength or channel selector tuner and an external
cavity tuner, wherein the wavelength tuner is uncoupled from the external cavity
tuner. The tuning mechanisms for wavelength selection and cavity optical path length
are configured to operate independently or orthogonally with respect to each other.
The wavelength tuner may operate according to a first, channel selection signal,
while the external cavity tuner operates according to a second, external cavity
adjustment signal. The wavelength tuner and external cavity tuner may operate under
the control of the same, or of separate controllers. The channel selection signal
may be derived from a look-up table of adjustment parameter data accessed by a
controller, and the external cavity adjustment signal may be derived from an error
signal from a detector configured to measure external cavity loss.
