Dynamic Spectral Equalizer动态光均衡器

1、dynamic spectral equalizerjoseph ford, james walker, david neilson, keith goossenreferences:ford, walker, goossen & neilson, european conference on optical communications 1999greywall, busch & walker, sensors & actuators a a72, 1999.ford, walker, greywall & goossen, ieee j. lightwave

2、 tech. 16, 1998goossen, arney & walker, ieee phot. tech. lett. 6, 1994l li but power divergence is inevitable spectral gain dependence in amplifiers is 1 db at best fixed wavelength add/drop creates divergence dynamic add/drop switching creates radical divergence gain saturation in amplifiers de

3、pletes weaker signals, and transmission nonlinearities limit maximum useful laser output powerl lidynamic gain equalizationl lil lisignals start out uniform source power adjusted by fixed line-build-out attenuatorsl liequalizerl lisolution: dynamic spectral equalizationl lil li basic: 2 nm resolutio

4、n over 35 nm passband, 0.5 sec response(resolves amplifier cascade nonuniformity) fancy: 50 ghz resolution (0.2 nm) over 70 nm band, 10 usec response(resolves wavelength add/drop dynamics)the “mars” resonant mems modulatormars (membrane anti-reflection switch) analog optical modulator l/4 silicon ni

5、tride “drumhead” suspended over a silicon substrate 0 vdrive 30v3l/4 gap l/2 inputl/4 sinxsiliconpsgreflecttransmitvdrive 0 vdrive 30v3l/4 gap l/2 inputl/4 sinxsiliconpsgreflecttransmitvdrivevoltage responsetheorymeasureddrive voltage (v)ford, walker, greywall & goossen, ieee j. lightwave tech.

6、16, 1998greywall, busch & walker, sensors & actuators a a72, 1999.goossen, arney & walker, ieee phot. tech. lett. 6, 1994mars equalizer devicematerial: 200 nm low-stress silicon-rich nitride on 1150 nm psg spacer membrane dimensions: 300 um x 1500 um (8x8 mm chip)actuators: 40 chrome-gol

7、d electrode pairs on a 32 micron pitchvoltageapplied silicon substratepsgelectrodes optical windowvoltageapplied ford & walker, ieee phot. tech. lett. 10, 1998reflection loss: 2.0 db 0v, 27 db 30vmechanically continuous membrane with segmented actuator electrodesfree-space wdm packageford, walke

8、r, goossen & neilson, european conf. on optical commun. 19993.7 db loss, 0.1 db pdl (incl. optical circulator)100 nm spectral range (5 mm active area)custom achromatic lens (athermal lens & kovar mechanics)i/o fiber(to circulator)electrical i/olens and l l/4f = 50mmmicromechanicalattenuator

9、arraygrating in tip/tilt mount600 lp/mm, 43o blaze anglegold-coated epoxy on zerudur substratewavelength (nm)ase power (db, relative to input)1520153015401550156015700-10-20-30-40-50initial ase (gain) spectraequalized ase (gain) spectramanual dynamic gain equalization filterford & walker, ieee p

10、hot. tech. lett. 10, 1998; ford, walker, goossen & neilson, european conference on optical communications 19991db11db6 db uniform insertion loss, 0.1 db pdl 0.1 ps polarization mode dispersion,0.5 ps/nm chromatic dispersion25 db dynamic range over 40 nm spectrumperformance:computer-controlled eq

11、ualizer prototypecontrol algorithm users program power setpoints computer estimates drive voltages* feedback from osa refines settingsford, walker, goossen & neilson, european conference on optical communications 1999optical spectrum analyzerrack-mounted pc controllerdgef & optical circulato

12、requalizer response model: membrane displacement estimated by adding lorentzian-shaped features with crosscoupling; optical response computed analytically. original “monet” amplifier 1st stage2nd stageinput power spectrum1525wavelength, nm0-10-20-30-40input power, dbm (schematic)-13 dbm/ch x 36 ch-1

13、8 dbm/ch x 36 ch1565-8 dbm/ch x 16 ch2 gain stageswith dcf port(7 db fixed loss)original amplifier design: 12 nm band & fixed input power 1 db output power divergence1525wavelength, nm0-10-20-30-40input power, dbm (schematic)-13 dbm/ch x 36 ch-18 dbm/ch x 36 ch1565-13 dbm/ch x 36 choriginal ampl

14、ifier design: 12 nm band & fixed input power 1 db output power divergenceextended operation? operating band to 30 nm input power range by 15 dboutput power spectrum1525wavelength, nm0-10-20-30-40input power, dbm (schematic)1565-18 dbm/ch x 36 ch-18 dbm/ch x 36 choriginal amplifier design: 12 nm

15、band & fixed input power 7 db loss divergence15250-10-20-30-40input power, dbm (schematic)1565wavelength, nm-23 dbm/ch x 36 chconventional erbium fiber amplifierauto-equalized amplifier1st stage2nd stagedgefpc controllerosatapinput power spectrum1525wavelength, nm0-10-20-30-40input power, dbm (s

16、chematic)-13 dbm/ch x 36 ch-18 dbm/ch x 36 ch1565-13 dbm/ch x 36 choriginal amplifier design: 12 nm band & fixed input power 1 db output power divergenceextended operation? operating band to 30 nm input power range by 15 dbadd equalizer at dcf port feedback output tap into osa1525wavelength, nm0

17、-10-20-30-40input power, dbm (schematic)1565-18 dbm/ch x 36 ch-18 dbm/ch x 36 choriginal amplifier design: 12 nm band & fixed input power 1 db output power divergenceextended operation: operating band to 30 nm input power range by 15 dbusing equalizer at dcf port: 20 db input power range 30 nm bandwidth15250-10-20-30-40input power, dbm (schematic)1565wavelength, nm-23 dbm/ch x 36 chau