During my Ph.D., I studied the potential of a bistable
laser (BL) diode as wavelength converter for all-optical telecommunication
system. This component is composed of a gain section and a saturable absorber
section. This confers a hysteresis loop between the input power or the injection
current and the output power. More control can be introduced by using another
smaller gain section adjacent to the saturable absorber section which commands
the width of the hysteresis loop. A phase section and a distributed Bragg
reflector can also be added in order to control the emitted wavelength of the
laser. The switching operation can be achieved by exploiting the hysteresis
loop. Biased under the hysteresis loop the BL can be switch on by an incoming
optical signal providing enough power to bleach the saturable absorber. The
lasing conditions are achieved and the laser is oscillating at its own
wavelength. When no power is injected, the saturable absorber recovers its
initial state and the BL stops emitting. If the input signal at a wavelength
represents a binary using this laser, we can convert the sequence at another
wavelength. The performance of the bistable laser has been assessed theatrically
and experimentally and published in peered reviews.
This
work was the subject of collaboration between Alcatel Research and the
Ecole Nationale Superieure des Telecommunication. It was partially supported by
the RACE ATMOS 2039 European contract.