Theoretical analysis of the wavelength tuning characteristics in a tunable ECDL based on a s-AFPF

Abstract

The single cavity all-dielectric thin film Fabry-Perot filter (s-AFPF) is investigated in this letter as a means of tuning the wavelength in an external cavity diode laser (ECDL), and the means of limiting longitudinal mode hopping is also investigated. When a TE or TM plane wave irradiates a s-AFPF, a quasilinear relationship is found in a certain wavelength range between the optical intensity peak-transmittance wavelength of s-AFPF and the cosine value of plane wave incident angle at s-AFPF. Based on this feature, we propose and investigate a configuration with a s-AFPF in a tunable ECDL. By theoretical calculation, a mode-hop-free wavelength tuning range of ∼5 nm around 1 550 nm is achieved. The ECDL can be used in the application of environmental monitoring, atomic and molecular laser spectroscopy research, precise measurements, and so on. OCIS codes: 140.2020, 140.3600, 310.6860. doi: 10.3788/COL201210.S11411. Tunable external cavity diode lasers (ECDLs) are playing an increasingly important role in coherent optical telecommunications, atomic and molecular laser spectroscopy, precise measurements, and environmental monitors [1] . Currently, two principal configurations in tunable ECDLs are the Littrow configuration [2−7] and the Littman–Metcalf configuration [8−11] and in both the