
IBM42S10SNNAA20
IBM42S10SNYAA20
1063/1250MBd Gigabit Interface Converter
IBM42S12SNYAA20
IBM42S10LNNAA20
IBM42S10LNYAA20
IBM42S12LNYAA20
IBM Corporation. All rights reserved.
Use is further subject to the provisions at the end of this document.
Page 16 of 34
GBIC.02
04/27/99
Notes for Short Wavelength Optical Characteristics
1. This 5.5dB optical power budget is a result of the difference between the worst case transmitted launch power and the receiver sen-
sitivity plus a 2dB optical path power penalty (as specified in the ANSI Fibre Channel specification): (-9.5dBm) - (-17dBm + 2dB) =
5.5dB.
2. Launched optical power is measured at the end of a two meter section of a 50/125
μ
m fiber for the GBIC-1063N, GBIC-1063NS, and
GBIC-1250NS, and a 9/125mm fiber for the GBIC-1063N-LW, GBIC-1063NS-LW, and GBIC-1250NS-LW. The maximum and mini-
mum of the allowed range of average transmitter power coupled into the fiber are worst case values to account for manufacturing
variances, drift due to temperature variations, and aging effects.
3. Optical rise time is determined by measuring the 20% to 80% response of average maximum values using an oscilloscope and 4th
order Bessel Thompson filter having a 3 dB bandwidth of 0.75
nominal baud rate. The measurement is corrected to the full band-
width value. Optical fall times are measured using a 6 GHz photodetector followed by a 22 GHz sampling oscilloscope. No correc-
tions due to filtering or system bandwidth limitations are made on the measured value.
4. Extinction Ratio is the ratio of the average optical power (in dB) in a logic level one to the average optical power in a logic level zero
measured under fully modulated conditions with a pattern of five 1s followed by five 0s, in the presence of worst case reflections.
5. RIN
12
is the laser noise, integrated over a specified bandwidth, measured relative to average optical power with 12 dB return loss.
See ANSI Fibre Channel Specification Annex A.5.
6. Eye opening is the portion of the bit time where the bit error rate (BER) is
≤
10
-12
. The general laser transmitter pulse shape charac-
teristics are specified in the form of a mask of the transmitter eye diagram. These characteristics include pulse overshoot, pulse
undershoot, and ringing, all of which should be controlled to prevent excessive degradation of the receiver sensitivity. When assess-
ing the transmit signal, it is important to consider not only the eye opening, but also the overshoot and undershoot limitations.
7. Deterministic Jitter is measured as the peak-to-peak timing variation of the 50% optical signal crossings when transmitting repetitive
K28.5 characters. It is defined in FC-PH, version 4.3, clause 3.1.87 as:
Timing distortions caused by normal circuit effects in the transmission system. Deterministic jitter is often subdivided into
duty cycle distortion (DCD) caused by propagation differences between the two transitions of a signal and data dependent
jitter (DDJ) caused by the interaction of the limited bandwidth of the transmission system components and the symbol
sequence.
8. Coupled Power Ratio is the ratio of average power coupled into a multimode fiber to the average power coupled into a single mode
fiber. The single mode fiber should be single mode at the wavelength of interest. This measurement is defined in EIA/TIA-526-14A.
Additionally, the values shall be time averaged while the multimode test jumper is shaken and bent to simulate temperature and time
variations of the laser.
9. The minimum and maximum values of the average received power in dBm allow the input power range to maintain a BER < 10
-12
when the data is sampled in the center of the receiver eye. These values take into account power penalties caused by the use of a
laser transmitter with a worst-case combination of spectral width, extinction ratio, and pulse shape characteristics.
10. The Rx_LOS has hysteresis to minimize
“
chatter
”
on the output line. In principle, hysteresis alone does not guarantee chatter-free
operation. These GBICs, however, present an Rx_LOS line without chatter, where chatter is defined as a transient response having
a voltage level of greater than 0.5 volts (in the case of going from the negate level to the assert level) and of any duration that can be
sensed by the host logic.