Characterization of Frequency Drift of Sampled-Grating DBR Laser Module Under Direct Modulation

Abstract

Abstract-The authors demonstrate the drift in frequency of a static sampled-grating distributed Bragg reflector (SG DBR) laser module when it is subjected to direct modulation. The magnitude of drift and its settling time is characterized as a function of the index of modulation. Results show that when the directly modulated SG DBR is optically filtered, as in a dense wavelength-division-multiplexed system, a power penalty of 6.7 dB is incurred in comparison to the unfiltered case. IndexTerms-Dense wavelength-division multiplexing (DWDM), direct intensity modulation, laser stability, optical fiber communications, tunable lasers (TLs).

Novel Frequency Chirp Compensation Scheme for Directly Modulated SG DBR Tunable Lasers

“…Nevertheless, one of the main drawbacks of this technique is the frequency fluctuation (chirp) imposed on the signal. This frequency chirp can impair the overall performance of WDM systems in two ways, either by drifting out of the receiving filter's bandwidth [2] and/or by drifting into the neighboring channel's filter bandwidth thereby causing cross channel interference. Additionally, the chirped signal would be more prone to dispersion effects in the fiber.…”

A micromachined tunable coupled-cavity laser for wide tuning range and high spectral purity

“…Furthermore, the limitations of optical and thermal properties of candidate DBR materials make it challenging to obtain large wavelength tuning range. On the other hand, more sophisticated tunable lasers with wide tuning ranges have also been developed, such as sampled grating distributed Bragg reflector (SGDBR) lasers [2,6], superstructure grating (SSG) DBR lasers [7] and high-contrast-subwavelength-grating (HCG) reflector based surface-emitting lasers [8,9]. In addition to the fabrication difficulties involving gratings and/or multiple epitaxial growths, the requirements to the reflector bandwidth and reflectivity become even more stringent.…”