Coupling effects in saturable gain media with interfering coherent optical amplifier pump beams

Summary form only given. We investigate special coupling effects in an Er-doped optical fibre amplifier, of which the gain medium is optically pumped by two mutually coherent counterpropagating pump waves that interfere inside the amplifier. The result is a unique filtering behavior where the signal gain becomes dependent on the wavelength and on the optical phases of the pump waves. This effect can be used for obtaining filters and single-mode operation of lasers. The wavelength of such a laser can be controlled by changing the wavelength or the phases of the pump waves. We have also shown previously that bidirectional pumping may cause bistability.