Laser dynamics providing enhanced-modulation bandwidth

Abstract

In the last decades, various solutions have been proposed to increase the modulation bandwidth and consequently the transmission bit rate of integrated semiconductor lasers. In this manuscript we review some of them, trying to analyze for each one the mechanisms producing the modulation bandwidth extension. A comparison of the various approaches used for in-plane lasers is presented, in terms of both small and large signal modulation responses calculated using a Finite Difference Time Domain (FDTD) numerical simulator.

Modeling of noise and distortion associated with ultra‐high‐speed modulation of VCSEL with slow‐light feedback

“…The peak value of the PPR peak is as large as 11 dB. Flat IM response could be obtained by careful adjustment of the PPR peak to fill the gap between the CPR and PPR peaks . This could be accomplished by operating the VCSEL under very strong lateral feedback.…”

Modeling of Millimeter-Wave Modulation Characteristics of Semiconductor Lasers under Strong Optical Feedback

“…It is interesting for applications such as the mm-wave RoF networks that require only a narrow bandwidth centered at a millimeterwave. To recover the modulation response over this unused gap and achieve flat IM responses, dispersive techniques may be needed at the end mirrors to obtain and allocate the photon-photon resonance at mm-frequency and achieve a wide carrier-photon resonance [21]. …”

“…Most recently the author's group [20] has newly reported using strong OFB to boost the modulation frequencies over an ultrahigh frequency passband over 55 GHz and has shown improvement of the gain of a corresponding RoF link by about 20 dB. Such enhancement in the IM response over an ultrahigh frequency passband was attributed as a type of photon-photon resonance due to coupling of oscillating modes in the coupled cavity [13, 21, 22]. It is obtained when the nonmodulated laser keeps operation in CW under strong OFB.…”