Modulation response of a long-cavity, gain-levered quantum-dot semiconductor laser

Abstract

Abstract:The gain-lever effect enhances the modulation efficiency of a semiconductor laser when compared to modulating the entire laser. This technique is investigated in a long-cavity multi-section quantum-dot laser where the length of the modulation section is varied to achieve 14:2, 15:1 and 0:16 gain-to-modulation section ratios. In this work, the gain-levered modulation configuration resulted in an increase in modulation efficiency by as much as 16 dB. This investigation also found that the 3-dB modulation bandwidth and modulation efficiency are dependent on the modulation section length of the device, indicating the existence of an optimal gain-to-modulation section ratio. The long cavity length of the multi-section laser yielded a distinctive case where characteristics of both the gain-lever effect and spatial effects are observed in the modulation response. Here, spatial effects within the cavity dominated the small-signal modulation response close to and above the cavity's free-spectral range frequency, whereas the gain-lever effect influenced the modulation response throughout the entirety of the response.

Enhancement of the Modulation Dynamics of an Optically Injection-Locked Semiconductor Laser Using Gain Lever

“…A 22 dB modulation efficiency increase was also realized using a 220-µm QW laser, with only a marginal increase in the intensity noise [25]. Recent results have also reported that the strong gain saturation in quantum dot (QD) lasers operating with GL effect can be beneficial for enhancing the 3-dB bandwidth at least by a factor of three as compared to the uniform bias condition [27], [28]. Such enhancements of the modulation efficiency with little effect on f R thus promises increased modulation bandwidths in GL DMLs.…”

Antiresonances and Ultrafast Resonances in a Twin Photonic Oscillator

“…Uncharacteristically, it has never called explicitly on the photonics literature of small signal modulation of semiconductor lasers. Still a careful review of recent work [39] and legacy literature [40] shows that it was evident in multiple experimental and theoretical graphs [41].…”

Complex Dynamics Induced by Asymmetry in Coupled Laser Systems

“…Interestingly, it seems to have passed unnoticed in the photonics literature of small signal modulation of semiconductor lasers. A careful review of recent work [52] and [53], however, reveals that it was evident in a number of experimental and theoretical studies [54].…”