Monolithic Tunable InAs/InP Broadband Quantum-Dash Laser

Abstract

A two-sectioned quantum dash laser structure based on an InAs/InP chirped active region medium is investigated as a monolithic broadband tunable laser. A thorough parametric analysis on the effect of three tuning parameters (viz. injection current, cavity length, absorber-to-device length ratio) on the optical power-injection current (L-I) and spectral characteristics, particularly wavelength tunability and bandwidth broadening, is performed. A total emission wavelength tunability of ∼20 nm is demonstrated in the mid-Lband (∼1600 to ∼1620 nm) window and ∼2 times enhancement in the 3dB bandwidth. Furthermore, optical bistability in the two-sectioned InAs/InP quantum-dash laser device is observed at near room temperature in the form of L-I curve hysteresis. Further investigation displayed a direct relation between the absorber length and the hysteresis loop width with a maximum value of ∼40 mA is demonstrated; a potential platform in fast optical switching and modulation applications. Finally, the two-sectioned structure is also proposed and investigated as a monolithic two-segment contact spectrum shaper to manipulate the lasing spectrum profiles to attain flat tops and effectively increase the spectrum 3dB bandwidth. As such, a maximum 3dB bandwidth was able to be pushed up to ∼20 nm from ∼7 nm by proper tuning of the current density distribution across the two segments of the device.

Injection-Locked Quantum-Dash Laser in Far L-Band 192 Gbit/s DWDM Transmission

“…To this end, self-assembled InAs/InP quantum dash (Qdash) nanostructure-based laser diodes emerge as potential light sources with demonstrated emission in a wide range of wavelengths covering the S-, C-, L-, and U-bands [5][6][7]. In particular, mid and far L-band Qdash laser diodes (QDLD) are of great interest from the outlook of future NG-PONs whose primary goal is maximizing the per-user capacity and increasing the number of possible subscribers, in addition to increasing the network range [1,2].…”

“…Moreover, these quantum confined nanostructure-based lasers possess niche features such as compact size, low power consumption, integrability in hybrid optical-silicon systems [8,9], and more importantly their inherent broadband gain profiles due to inhomogeneous dash sizes owing to the selfassembly growth process. Although this latter feature seems a disadvantage for lasers, however, has been exploited to realize 1550 nm multiwavelength QDLD or comb sources [7], which has consequently, qualified them as promising contenders for source-unified NG-PON paradigms [10].…”