Experimental characterization of the frequency modulation behavior of vertical cavity surface emitting lasers

Abstract

The frequency response of the current-to-wavelength tuning rate (FM response) was measured for two different vertical cavity surface emitting lasers (VCSELs) up to frequencies of 1MHz: GaAs-based VCSEL (763nm) and InP-based VCSEL (1853nm). Both of them show the same qualitative FM response behavior, which can be described by a square root law and therefore cannot be modeled by a first order low pass. The square root law behavior is a significant advantage for laser spectroscopy applications with VCSELs because the decrease of the current-to-wavelength tuning coefficient is less severe as in the case of the first order low pass.

Frequency modulation characteristics for interband cascade lasers emitting at 3 μm

“…We determine FM efficiency and FM response by measuring the second-harmonic (2f) spectrum of WMS absorption signals as reported by Chen [11]. The distance (Δv z ) between two zero crossings of the measured 2f spectrum is evaluated to infer the wavelength modulation amplitude Δv.…”

“…However, Lytkine et al [9,10] measured the FM efficiency and IM/FM phase shift for a 1.5-μm vertical-cavity surface-emitting laser (VCSEL) and identified differences with respect to Schilt's results, mainly caused by the different excitation modes between VCSELs and DFB DLs. Chen et al [11] measured the FM efficiency of a GaAs VCSEL (lasing wavelength of 0.76 μm) and an InP VCSEL (lasing wavelength of 1.85 μm) and established an empirical model of FM response, which followed a square root law but not a first-order low-pass law. Next, Chen et al theoretically analyzed and verified the measured square root law of the FM response of VCSELs based on the thermal tuning theory of VCSELs.…”

Residual Amplitude Modulation Method Implemented at the Phase Quadrature Frequency of a 1650-nm Laser Diode for Line Shape Recovery of Methane

“…The amplitude of all the signals decreases rapidly with increase in f m . This is expected because ξ is known to decrease with increasing f m [30]- [32]. The signal along this axis has a small background DC level which decreases with increasing f m .…”

Vertical-Cavity Surface-Emitting Laser Light–Current Characteristic at Constant Internal Temperature

“…By applying a small-signal modulation with frequency well above the thermal cutoff frequency and below the relaxation frequency (here MHz [7]) the slope of the --characteristic at constant junction temperature is determined. Knowing the slope and the laser output power , the full internal --characteristic can be reconstructed.…”