Author Affiliations
1School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, China2Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China3Institute of Atomic and Molecular Science, Shaanxi University of Science and Technology, Xi’an 710021, China4The Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China5Division of Nanomaterials, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Nanchang 330200, Chinashow less
Fig. 1. (Color online) External cavity feedback semiconductor laser. (a) Block diagram. (b) Equivalent model.
Fig. 2. (Color online) (a) Illustration of the role of factor A. (b) Illustration of factor B (optical negative feedback).
Fig. 3. (Color online) The relationship between the external cavity length, the waveguide loss and the intrinsic linewidth of the laser [36].
Fig. 4. (Color online) Optical path extension under different coupling coefficients and different losses.
Fig. 5. (Color online) (a) SSC structure diagram[42]. (b) Heterogeneous integration[41].
Fig. 6. (Color online) The intrinsic linewidth of hybrid integrated laser based on butt coupling technology: a-[43], b-[44], c-[45], d-[46], e-[47], f-[48], g-[49], h-[50], i-[51], j-[52], k-[53], l-[54], m-[55], n-[56], o-[57], p-[58], q-[59], r-[60], s-[61], t-[62], u-[63], v-[64].
Fig. 7. (Color online) Schematic view of the hybrid laser based on a Si3N4 feedback circuit comprising a spiral and three MRRs[64].
Fig. 8. (a) Laser structure diagram based on triple MRR. (b) Frequency noise spectrum[76].
Platform | Propagation loss (dB/cm) | Group index | Refractive index contrast |
---|
SiON/SiO2[27] | 0.05 | 1.4816 | 0.025 | SiO2/Si[28] | 0.023 | 1.465 | 0.02 | Si-wire/SiO2[29] | 2.4 | 3.47 | – | Si3N4/SiO2[30] | 0.013 | 1.996 | 0.5 | Ultralow-loss SOI[31] | 0.16 | 3.61 | 2.145 |
|
Table 1. Optical properties of the waveguide external cavity platforms.
First author | Structure | SMSR
(dB)
| Tuning range
(nm)
| Min. linewidth
(kHz)
|
---|
Hulme[70] | MRR | 35 | 40 | 338 | Komljenovic[71] | MRR + LR | 45 | 54 | 50 | Komljenovic[72] | MRR | >40 | 29 | 260 | Liang[73] | MRR + LR | >40 | 40 | 150 | Tran[74] | MRR + LR + MZI | >50 | 55 | 50 | Huang[75] | Grating | >55 | – | 1 | MRR + Grating | – | 0.5 | Tran[76] | Dual MRR + LR | >45 | 40 | 2 | Triple MRR + LR | >40 | 110 | <0.22 |
|
Table 2. The performances of heterogeneous integrated lasers.