Abstract

With the recent advances in erbium-doped fiber amplifiers, the transmission distance is no longer loss limited but rather fiber dispersion limited. By the use of wavelength multiplexing, the bit rate of each wavelength can be substantially lower than the aggregated bit rate, such that not only cost-effective electronics are available but also the maximum transmission distance can be substantially increased. Moreover, the wavelength can be used as an address to route information without going through opto-electronic conversion. Recently, DARPA has funded a project on all optical network to study the potential of multi-wavelength switching.¹ A substantial part of the total cost for a packaged DFB laser module is the packaging cost to include a fiber pigtail, a thermoelectric cooler and an optical isolator. The total cost of a multi-wavelength laser transmitter made of discrete packaged DFB laser modules is proportional to the number of wavelengths. For WDM lightwave systems to be cost effective, it is desirable to fabricate the multi-wavelength laser transmitters by photonic integration to reduce the per wavelength cost of packaging and control circuitry by sharing them among all the wavelengths.

© 1993 Optical Society of America