Lecture11-228a

Lecture11-228a - ECE 228A Fall 2011 Daniel J. Blumenthal...

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Unformatted text preview: ECE 228A Fall 2011 Daniel J. Blumenthal 11.1 Lecture 11 -Optical Sources and Transmitters ECE 228A Fall 2011 Daniel J. Blumenthal 11.2 Table 1 - MSA Standards Overview Multi -Source Agreement Synopsis Serial Transceivers SFP Small Form Factor Pluggable popular mainstream pluggable for data rates to 2.5 Gb/s, up to 4 Gb/s Fiber Channel SFP+ being promoted for 10 Gb/s QSFP for 4 channel implementations DWDM versions avail able for Metro telecom systems www.sffcommittee.org XFP 10G Small Form Factor Pluggable 10GbEthernet, OC192, (10G FC anticipated) Available in non -WDM, CWDM and DWDM versions Available to 80 km reach www.xfpmsa.org 10 Gbit Ethernet Transponders Xenpak XAUI electrical interface Hot pluggable Large legacy market www.xenpak.org Xpak / X2 Functionally equivalent to Xenpak, but XPAK and X2 are two rival mechanical designs in a smaller form factor. Designs do not require card cutout. Www.x2msa.org www.xpak.org Other Selected Transponder Module MSAs 300pin Fixed pluggable transponder SFF (Small Form Factor) version more space efficient Large power dissipation budget allows advanced (high power) functions to be implemented 10GbE and OC192 Sonet/SDH Tunable Laser versions available. www.300pinmsa.org Parallel Optics SNAP12, POP4, Quadlink 12 channel and 4 channel parallel optics modules for very short reach, ultra high bandwidth applications. www.snapoptics.org www.popoptics.org ECE 228A Fall 2011 Daniel J. Blumenthal 11.3 Photon Energy and Bandgap Energy of Photon E a E b = h = E g + h 2 k 2 2 m c + h 2 k 2 2 m v For an electron in upper state a and potential lower state b, the downward rate of transition is R a b f c ( E a ) 1 f v E b ( ) $ % & ' Effective inversion due to electrons and holes within d k N 2 N 1 ( k ) dk V f c ( E a ) 1 f v ( E b ) [ ] f v ( E b ) 1 f c ( E a ) [ ] { } = ( k ) dk V f c ( E a ) f v ( E b ) [ ] ECE 228A Fall 2011 Daniel J. Blumenthal 11.4 Forward biased p-n junction Spontaneous Emission Electroluminescence P-type N-type Light is emitted from forward biased junction in all directions Light Emitting Diodes (LEDs) ECE 228A Fall 2011 Daniel J. Blumenthal 11.5 Internal optical power P int = int I q " # $ % & ( h ) = # photons sec " # % & energy photon " # $ % & LED Optical Characteristics Output optical Power Important: the output optical power is (to a frst instance) proportional to the driving current: h q I P P int ext int ext out = = Internal quantum efciency Output coupling efciency ) ( ) ( out t I k t P ECE 228A Fall 2011 Daniel J. Blumenthal 11.6 Full width half maximum spectral width: it is roughly given by: Note that it is directly proportional to the device temperature T ch T K h T K B B 2 8 . 1 8 . 1 Ex : GaAs LEDs (830 nm, 300 K) 30 nm InGaAsP LEDs (1310 nm, 300 K) 60 nm LED Spectral Width ) ( f P out The output optical power (coupled in the output ber pigtail) for most commercial LED is in the order of 20 dBm to 10 dBm ECE 228A Fall 2011 Daniel J. BlumenthalECE 228A Fall 2011 Daniel J....
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This note was uploaded on 11/24/2011 for the course ECE 228a taught by Professor Bowers,j during the Fall '08 term at UCSB.

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Lecture11-228a - ECE 228A Fall 2011 Daniel J. Blumenthal...

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