Ultrafast intersubband optical switching in II–VI‐based quantum well for optical fiber communications

Abstract

PACS 42.65. Pc, 78.67.De Ultrafast all-optical switching at optical communication wavelength has been investigated by utilizing an intersubband transition (ISBT) of II -VI-based multiple quantum wells (MQWs) fabricated in high-mesa waveguide devices. At first, we have achieved λ ~ 1.55 µm ISBT absorption in (CdS/ZnSe)/BeTe QWs. The QWs consists of Cl-doped CdS/ZnSe well and BeTe barrier. The ISBT optical nonlinearity in the wafer sample exhibits sub-ps relaxation time and sub-pJ/µm 2 saturation energy, indicating a promising characteristic for high-speed switching. The waveguide device fabricated consists of a CdS/ZnSe/BeTe MQWs core layer and two top and bottom ZnMgBeSe quaternary cladding layers. Ultrafast gate switching within a time window of 0.56 ps was demonstrated with pump pulse at λ = 1.57 µm and probe pulse at λ = 1.63 µm in this waveguide device.

Optically controlled resonance energy transfer: Mechanism and configuration for all-optical switching

“…Many efforts to deploy silicon as the basis for optical switching systems and devices have proved problematic due to the relatively weak nonlinear optical properties of the material, although some successes have been reported. 1,2 A great deal of research activity now centers on semiconductor quantum well systems [3][4][5][6][7][8][9][10] that offer opportunities to exploit the inter subband excitation transitions of confined electrons, associated with ultrafast relaxation. Based on similar principles, the feasibility of using carbon nanotubes, of morphology appropriate for all-optical switching, has also been demonstrated.…”

All-optical switching based on controlled energy transfer between nanoparticles in film arrays

“…In equation (5) the second-order contribution (2) fi M corresponds to RET -a null quantity for the configurations described in this paper. Substituting equation (4) sin cos sin KC J P t r…”

“…Numerous technical strategies have been entertained, and many are the subject of vigorous ongoing research. These include: semiconductor quantum wells systems [2][3][4][5], where optical switching is conceived as an exploitation of optical saturation -although an alternative method, based on atomic quantum interference in electromagnetic induced transparency has recently been demonstrated [6][7][8]; photonic crystals with cross-waveguide geometries, offering switching action through the optical Kerr effect [9][10][11]; surface plasmon polariton media, in which light-induced dielectric modification at an interface affects the transmission of throughput radiation [12][13][14]; and various schemes based on films of bacteriorhodopsin, a light harvesting protein with unique non-linear optical properties [15][16][17]. One possibility that has only recently begun to attract attention is an all-optical switching mechanism based on the optical control of resonance energy transfer (RET) between particles.…”

Shorter wavelength intersubband absorption down to λ = 1.55 µm in (CdS/ZnSe)/BeTe type‐II superlattices

“…The high ionicity in CdS and ZnSe compounds speeds up carriers relaxation by enhancing the interaction of electrons and LO phonons. Recently, we have found that recovery time becomes faster with shorter wavelength (350 fs at λ = 1.8 µm and 150 fs at λ = 1.55 µm) in this structure [3].…”