1 / 13

16.711 Lecture 9 Optical Fiber Amplifier – PDL, Transient, Cross-talk

16.711 Lecture 9 Optical Fiber Amplifier – PDL, Transient, Cross-talk. Last Lecture. Amplifier Noise OSNR and BER System Applications . 16.711 Lecture 9 Optical Fiber Amplifier – PDG, Transient, Cross-talk. Today. Polarization dependent gain (PDG) ASE induced Time Jitter

Thomas
Télécharger la présentation

16.711 Lecture 9 Optical Fiber Amplifier – PDL, Transient, Cross-talk

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. 16.711 Lecture 9 Optical Fiber Amplifier – PDL, Transient, Cross-talk Last Lecture • Amplifier Noise • OSNR and BER • System Applications

  2. 16.711 Lecture 9 Optical Fiber Amplifier – PDG, Transient, Cross-talk Today • Polarization dependent gain (PDG) • ASE induced Time Jitter • Cross-talk, spectral hole burning and gain clamping • Transient • Amplifier Examples

  3. 16.711 Lecture 9 Optical Fiber Amplifier – PDG, Transient, Cross-talk Polarization Dependent Gain (PDG) • Why PDG is important? • Where the PDG originates? (1) Polarization difference between Maximum ASE and the signal PDG ~ 0.01dB (2) Polarization difference between pump laser and the signal PDG ~ 0.05dB

  4. 16.711 Lecture 9 Optical Fiber Amplifier – PDG, Transient, Cross-talk Polarization Dependent Gain (PDG) • PDG and input signal Power

  5. 16.711 Lecture 9 Optical Fiber Amplifier – PDG, Transient, Cross-talk Polarization Dependent Gain (PDG) • Solution to reduce PDG: Polarization scrambling • Improve Q factor by 2dB

  6. 16.711 Lecture 9 Optical Fiber Amplifier – PDG, Transient, Cross-talk ASE induced time jitter • What is time jitter? • Why time jitter is important? • ASE induced time jitter (1) ASE generated carrier density fluctuation (2) Index change due to the carrier density fluctuation --- time jitter • Analysis is complex, approximately:

  7. 16.711 Lecture 9 Optical Fiber Amplifier – PDG, Transient, Cross-talk Transient effect • Two important time scales in Optical amplifier: (1) Stimulated emission: ~ ps (2) Carrier life-time at energy level ~ ms ms ps

  8. Population density of the upper level • response only to the average signal power for bit rate >10Kb/s. 16.711 Lecture 9 Optical Fiber Amplifier – PDG, Transient, Cross-talk Transient effect

  9. 16.711 Lecture 9 Optical Fiber Amplifier – PDG, Transient, Cross-talk Transient effect • Change of population density of the upper level • takes ~ 1ms to settle down.

  10. 16.711 Lecture 9 Optical Fiber Amplifier – PDG, Transient, Cross-talk Transient effect • Ways to reduce the Transient effect. (1) Pump feedback to keep constant population density (2) Gain clamping, --- keep the constant input power.

  11. 16.711 Lecture 9 Optical Fiber Amplifier – PDG, Transient, Cross-talk Cross-talk, multi-channel amplifying • Any multi-channel cross-talk when all channel present? • Why not, (valid Only for EDFA) ? • Cross-talk when a channel is turned on and off.

  12. 16.711 Lecture 9 Optical Fiber Amplifier – PDG, Transient, Cross-talk Examples • Preamp --- receiver sensitivity improvement by EDFA: • Preamp --- receiver sensitivity improvement not valid for Pin arbitrary small.

  13. 16.711 Lecture 8 Optical Fiber Amplifier – noise and BER Receiver noise Total photo-detector current: R is the resistance of the detector load resistor. Total ASE power:

More Related