Devices for 100 Gb/s communications

Abstract

Summary form only given. Ultrahigh bandwidth communication can be accomplished by either wavelength or time division multiplexing, or both. A logical route is to advance TDM as far as possible and then implement WDM after a reasonable limit has been reached. Recent experiments have demonstrated that TDM channels can be produced that can carry up to 400 Gb/s and sent up to 80 km. In order to make this technology practical, optical devices that can generate, encode, multiplex and demultiplex these high bit rate signals must be developed. In our laboratory we have been using a test system operating at 100 Gb/s (8 channels of 12.5 Gb/s) to develop technologies compatible with these goals. In TDM systems that require return to zero coding, there is the possibility, depending on the energy and dispersion of the pulses to use either linear propagation or soliton propagation of the pulses. The optical source used for our test system is a harmonically mode-locked fiber laser capable of producing 1.5 ps pulses at repetition rates between 8 and 15 GHz. Multiplexing of independently modulated bit streams into a single 100 Gb/s stream can be accomplished with fiber optic couplers if care is taken to correctly phase the channels. In our laboratory, for test purposes we have implemented a 1/spl times/8 multiplexer based on 45' spliced PM fiber. The result is a 100 Gb/s pseudorandom bit stream where each channel has the same bit pattern, facilitating the testing of the system devices. Many types of demultiplexers have been proposed for these systems, and some have been demonstrated. We have demonstrated a polarization multiplexed nonlinear mirror demultiplexer, and have also developed a demultiplexer based on integrated optic modulators which should be able to perform not only demultiplexing, but also add-drop functions at these bit rates.