Contents 1. Introduction
Tunable lasers are a key technology in wavelength routed optical networks [1]. Although many tunable sources have been researched, recently, an approach based on mode-locked lasers has received attention [2] [3] [4]. We call, this type of source a time-to-wavelength mapped laser (TWML). The cavity of a TWML is made to have a length that depends on wavelength . When the laser is mode-locked at a frequency that matches a resonance. frequency of the cavity of length , the corresponding wavelength oscillates but all others experience loss. Hence, the laser emits pulses at wavelength and repetition rate , By changing the modulation frequency, the wavelength of the laser can be selected. Although the varying repetition rate may seem problematic for establishing communications at a fixed data rate R, we have proposed to’ use these sources when , The data at a fixed rate is then carried as' an envelope of the pulse train. Although there are performance degradations and inherent speed limitations associated with such a modulation scheme, it may find use jn LAN or MAN environments, where the transmission distances are short and the data rates are low (2.5 Gbps or less), This general type of laser also offers the potential for simple addressing schemes using a subcarrier tone [5].
