A directly modulated distributed feedback (DFB) laser with improved
optical field uniformity and mode stability may include a laser cavity
and a distributed reflector and/or external reflectors. The distributed
reflector may be a Bragg grating and may extend asymmetrically over a
only portion of the laser cavity. The external reflectors may themselves
be distributed Bragg reflectors and may have unequal reflectances.
Optical field uniformity may be improved by adjusting the length and/or
position of the distributed reflector in the laser cavity. Optical field
uniformity may be improved by adjusting a coupling strength parameter,
which is a function of a coupling coefficient, .kappa., and the length of
the distributed reflector.