Modeling noise and modulation performance of fiber grating external cavity lasers

Abstract

A detailed model is developed for analyzing fiber grating external cavity lasers for both static and small-signal modulation conditions. The chip and package parasitics and leakage current induced distortion are included. The composite system is solved analytically in the small-signal regime using a Volterra functional series expansion method. As an application of the model, a thorough analysis of the appearance of nulls close to the harmonics of the cavity resonance frequency in the noise and modulation spectra is given. We show that the appearance of these nulls can be explained using the interplay of amplitude and phase coupling between laser diode and external resonant cavity. A signal flow graph approach is introduced which identifies methods of minimizing the nulls.

Small signal intensity modulation of external cavity lasers with fiber Bragg gratings

“…Magnitude continues disappear for large value a as expected. These results show that a is a significant effect on RPSS as references (Premaratne et al 1997;Pittoni et al 2001). …”

“…They related the resonance-peak splitting in IM response to the resonance-peak splitting in RIN. Premaratne et al (1997) showed that RPSS in noise and modulation spectra results from the complex amplitude-phase coupling interplay between active and passive resonant cavities. Spectral splitting is due to interactions between the field amplitudes and phases in the laser and the external cavity and significant amplitude-phase coupling is necessary for the appearance of spectral splitting Premaratne et al (1997).…”

“…Now effect of these parameters and the other laser and FBG parameters will be identified and results will be compared in (Ahmed and Tucker 1995;Premaratne et al 1997). Fig.…”

“…Spectral splitting is due to interactions between the field amplitudes and phases in the laser and the external cavity and significant amplitude-phase coupling is necessary for the appearance of spectral splitting Premaratne et al (1997). The origin of the this amplitude discontinuity was investigated in (Ahmed and Tucker 1995;Premaratne et al 1997) and they showed that large AR coating field reflectivity (r 3 ), poor coupling between active and passive cavities (g), low gain compression factor (e), linewidth enhancement factor (a), external cavity length have a significant effect on RPSS.…”

“…In Ahmet and Tucker (1995) small signal intensity modulation (IM) responses of external cavity lasers without fiber Bragg grating (FBG) has been described. Origin of the resonance peak spectral splitting (RPSS) in the IM spectra of FBG laser has been explained in Premaratne et al (1997) and Pittoni et al (2001) has also shown that optimum modulation frequencies can be found with a systematic analysis of the IM response of the device. In this paper small signal IM response of HSPS utilizing Gaussian apodized FBG is presented.…”