Optical coupling of adjacent stripe contact geometry semiconductor lasers

Claim 1

An optical scanner comprising, in combination, a body of semiconductor material having a pair of spaced parallel reflecting surfaces forming an optical cavity resonator therebetween for sustaining radiation generated by stimulated emission in said body, at least one of said reflecting surfaces being partially transmissive to permit egress of output radiation from said resonator, said body comprising a first semiconductor layer of a first conductivity type, a second semiconductor layer of the opposite conductivity type contiguous with said first layer and forming therebetween a planar p-n junction disposed normal to said reflecting surfaces, said resonator having an optic axis extending normal to said reflecting surfaces and a transverse axis extending normal to said optic axis and parallel to said p-n junction, means for pumping said body to produce said stimulated radiation comprising means for forward biasing said p-n junction and for applying thereto current in excess of the lasing threshold, means for causing said output radiation to change the angle which it makes with said partially transmissive reflecting surface in response to an information signal f(t) comprising a first and second plurality of parallel stripe electrical contacts disposed on a major surface of said body parallel to said optic axis and to said p-n junction, said first and second pluralities being electrically insulated from one another along a region defined by a linear relationship between the lengths of said contacts along said optic axis and the position of said contacts on said major surface along said transverse axis, each of the contacts in each of said pluralities of contacts being substantially rectangular in shape and having a corresponding complementary contact in the other of said pluralities, each of said contacts and its corresponding complementary contact lying along a common axis parallel to said optic axis, and the sum of the length of any one of said contacts in one of said pluralities and the length of the corresponding complementary contact in the other of said pluralities being equal to a constant, each of said contacts forming a separate one of a plurality of junction lasers and the separation of adjacent edges of said contacts being no more than about 12 Mu m so that the optical fields of adjacent lasers overlap and cause said lasers to phase lock to one another, a first current source connected in series with each of the contacts in one of said pluralities to produce in the region of said junction theReunder a current density JA Jo + af(t) where a is a constant, f(t) defines the time variation of the amplitude of said information signal about an average current density level Jo, and a second current source connected in series with each of the contacts in the other of said pluralities to produce in the region of said junction thereunder a current density JB Jo af(t), thereby to scan the main lobe of said output radiation at an angle Beta to the normal to said plurality transmissive reflecting surface as a function of said information signal f(t), where sin Beta Alpha lambda /2 pi d, lambda is the wavelength of the phase locked output radiation, d is the distance between the centers of adjacent stripe contacts and Alpha , a constant phase difference between the outputs of adjacent ones of said lasers, is proportional to (JA - JB) 2af(t).