Abstract

High saturated gain, low distonion and low noise seem to be the three essential technical characteristics required to make the optical amplifiers suitable for AM-SCM video systems.¹ High saturated gain (20-dBm output optical power for 0 dBm input) and low noise (close to 3-dB noise figure) have already been reported/ It was shown by Chen et al. that the second-harmonic distortion due to the intrinsic gain dynamics of the EDFA should be lower than −120 dBc at 100 MHz.³ However, in the presence of laser chirp, Kuo and Bergmann have shown that, if the EDFA gain depends on wavelength, the composite second order (CSO) distortion can be as high as −45 dBc at 55.25 MHz (channel 2) with 42 NTSC channels and 5% optical modulation index (OMI).⁴ We report a 980-nm diode-pumped EDFA with a very flat gain profile and very low distortion.

© 1992 Optical Society of America