MCQOPTIONS
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MCQOPTIONS
This section includes 14 Mcqs, each offering curated multiple-choice questions to sharpen your Optical Communications knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The active layer of E-LED is heavily doped with ____________ |
| A. | Zn |
| B. | Eu |
| C. | Cu |
| D. | Sn |
| Answer» B. Eu | |
| 2. |
The InGaAsP is emitting LEDs are realized in terms of restricted are ____________ |
| A. | Length strip geometry |
| B. | Radiance |
| C. | Current spreading |
| D. | Coupled optical power |
| Answer» B. Radiance | |
| 3. |
Mesa structured SLEDs are used ____________ |
| A. | To reduce radiance |
| B. | To increase radiance |
| C. | To reduce current spreading |
| D. | To increase current spreading |
| Answer» D. To increase current spreading | |
| 4. |
The overall power conversion efficiency of electrical lens coupled LED is 0.8% and power applied 0.0375 V. Determine optical power launched into fiber. |
| A. | 0.03 |
| B. | 0.05 |
| C. | 0.3 |
| D. | 0.01 |
| Answer» B. 0.05 | |
| 5. |
Determine the overall power conversion efficiency of lens coupled SLED having forward current of 20 mA and forward voltage of 2 V with 170 Wof optical power launched into multimode step index fiber. |
| A. | 1.256*10<sup>-5</sup> |
| B. | 4.417*10<sup>2</sup> |
| C. | 4.25*10<sup>-3</sup> |
| D. | 2.14*10<sup>-3</sup> |
| Answer» D. 2.14*10<sup>-3</sup> | |
| 6. |
In a multimode fiber, much of light coupled in the fiber from an LED is ____________ |
| A. | Increased |
| B. | Reduced |
| C. | Lost |
| D. | Unaffected |
| Answer» D. Unaffected | |
| 7. |
Estimate optical power coupled into fiber of DH SLED having emission area of 1.96*10-5, radiance of 40 W/rcm2, numerical aperture of 0.2 and Fresnel reflection coefficient of 0.03 at index matched fiber surface. |
| A. | 5.459*10<sup>-5</sup> |
| B. | 1.784*10<sup>-3</sup> |
| C. | 3.478*10<sup>2</sup> |
| D. | 9.551*10<sup>-5</sup> |
| Answer» E. | |
| 8. |
A DH surface emitter LED has an emission area diameter of 60 m. Determine emission area of source. |
| A. | 1.534*10<sup>-6</sup> |
| B. | 5.423*10<sup>-3</sup> |
| C. | 3.564*10<sup>-2</sup> |
| D. | 2.826*10<sup>-9</sup> |
| Answer» E. | |
| 9. |
DH surface emitter generally give ____________ |
| A. | More coupled optical power |
| B. | Less coupled optical power |
| C. | Low current densities |
| D. | Low radiance emission into-fiber |
| Answer» B. Less coupled optical power | |
| 10. |
Internal absorption in DH surface emitter Burros type LEDs is ____________ |
| A. | Cannot be determined |
| B. | Negligible |
| C. | High |
| D. | Very low |
| Answer» E. | |
| 11. |
In surface emitter LEDs, more advantage can be obtained by using ____________ |
| A. | BH structures |
| B. | QC structures |
| C. | DH structures |
| D. | Gain-guided structure |
| Answer» D. Gain-guided structure | |
| 12. |
As compared to planar LED structure, Dome LEDs have ______________ External power efficiency ___________ effective emission area and _____________ radiance. |
| A. | Greater, lesser, reduced |
| B. | Higher, greater, reduced |
| C. | Higher, lesser, increased |
| D. | Greater, greater, increased |
| Answer» C. Higher, lesser, increased | |
| 13. |
In optical fiber communication _____________ major types of LED structures are used. |
| A. | 2 |
| B. | 4 |
| C. | 6 |
| D. | 3 |
| Answer» D. 3 | |
| 14. |
The amount of radiance in planer type of LED structures is ____________ |
| A. | Low |
| B. | High |
| C. | Zero |
| D. | Negligible |
| Answer» B. High | |