Enhanced frequency modulation in cleaved coupled cavity (C3) semiconductor diode lasers has recently been reported [1,2], in this operating mode the ''laser" segment “a” is biased above threshold, whereas the pump current to the "modulator" segment "b" is maintained below its threshold value (see Fig. 1). As the modulator current is varied, the optical frequency shifts and that change is an order of magnitude greater than observed with conventional diode lasers. We report the first analysis of this phenomenon and study the various factors influencing device behavior including gap spacing and bias point. Enhanced understanding of device limitations and capabilities enable the determination of optimal operating points for existing devices and is useful for developing an optimal design.
© 1984 Optical Society of AmericaPDF Article