Analytical Models for External Cavity Lasers Using Tunable Etalons

Recently, external-cavity tunable lasers (ECTLs) have been widely used in WDM systems for their excellent characteristics, such as high side-mode suppression ratio (SMSR), low relative intensity noise (RIN) and narrow line width. In this paper, we propose an analytical model for external-cavity lasers using tunable etalons and elaborate on the selection of key parameters in the design scheme, which is rarely discussed in detail in previous researches. By numerically solving the model based on the rate equation and the transmission matrix, we analyzed the effects of different end-facet reflectivity on the SMSR, PI curves, electron and photon concentration distributions. In addition, By choosing appropriate physical parameters, we theoretically demonstrate an ECTL with a single wavelength tuning range of 1570.5–1603.6 nm (186.95–190.9 THz), and a power efficiency of 0.673 W/A, as well as an SMSR exceeds 50 dB.