1.5-μm and 10-Gb s⁻¹ etched mesa buried heterostructure DFB-LD for datacenter networks

Abstract

We report a 1.5 μm and 10 Gb s −1 etched mesa buried heterostructure λ/4-shifted distributed feedback laser diode (DFB-LD) for the low-cost application of WDM-based datacenter networks. To reduce the threshold current and improve the modulation bandwidth in a conventional p-/n-/p-InP current blocking structure, a thin undoped-InP (u-InP) layer was inserted between the side walls of the active region and the p-InP layer (i.e., a u-/p-/n-/p-InP structure), and the region containing the active region and the current blocking structures was etched in a mesa form (i.e., an etched mesa). From this work, it was found that a 300 μm long anti-reflection (AR)-AR DFB-LD with a mesa width of 8 μm is reduced by about 25% while a side mode suppression ratio is >50 dB and a 3 dB bandwidth is >10 GHz at a current of 40 mA; in addition, it shows a clear eye-opening with a dynamic extinction ratio of >4.5 dB at 10 Gb s −1 , and a power penalty of <1 dB after a 2 km transmission.

Dynamic Device Characteristics and Linewidth Measurement of InGaN/GaN Laser Diodes

“…From here, using known values for constants contained within D [40], as well as values calculated for vg, Γ, and V through simulations using RSoft's LaserMOD software tool, a differential gain of g' = 7.42 x 10 -16 cm 2 was estimated. For lasers in more well established materials such as InP and GaAs, D and g' are typically an order of magnitude higher [18,22,23], however in previous reported works for GaN FP devices, D was found to be significantly lower, ranging from ~0.1 GHz/mA 0.5 [27] to ~0.5 GHz/mA 0.5 [28]. Finally, from the values found for fr and γ, the intrinsic response was found for the GaN DFB.…”

“…A narrow spectral linewidth ensures that minimal chromatic dispersion occurs, and for quantum applications such as atomic clocks the linewidth frequency must be narrower than the atomic transition being targeted, ensuring that atoms can be cooled efficiently [16]. Whilst these parameters have been well established in InP [17][18][19] and GaAs [20][21][22][23] DFB lasers, this is not the case for GaN devices. GaN LEDs have been the subject of vigorous research in terms of their recombination coefficients [24][25][26], while modulation efficiency and differential gain have been reported only for GaN FPs [27,28].…”

100-Gb/s/λ PAM-4 EAM-Integrated DBR-LD Supporting Multiple Sub-Channels Within 1.29 μm Window

“…After the PL test, the active region and core layer in the tuning sections and the SSC were etched to widths of approximately 1.2, 1.2, and 0.6 µm, respectively. For the waveguide structure of the device, the DBR-LD and SSC were fabricated into an etched-mesa buried hetero-structure (EMBH) [7], [20] with a width of 12, 9, 8 µm for the gain and tuning sections and the SSC, respectively, and the EAM was made into a deep ridge waveguide (DRWG) with a width of approximately 2.2 µm. A 3D beam propagation method (BPM) simulation was conducted to analyze the beam propagation properties of the SSC, as shown in Fig.…”

Improvement of Power and Efficiency of High-Mesa Semi-Insulating InP: Fe Buried Heterostructure Lasers with Wide Bandgap Layers

“…Firstly, almost all BH lasers suffer from severe leakage currents under high current injections because existing BH structures inevitably introduce leakage current channels [4][5][6] during selective area growth (SAG), together with the diffusion of Zn near an active region [7]. Secondly, Fe-doped InP will lose semi-insulating (SI) properties in the p-doped environment due to double injection [4,8,9].…”