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IBM42M10SCYAA10
IBM42M10LCYAA20
1063Mb/s Gigabit Link Module
Page 20 of 30
glm1063.02.fm.02
Feb. 15, 2000
Optical Characteristics
Short Wavelength
Parameter
Symbol
Min.
Typical
Max.
Units
Notes
Optical Power Budget
OPB
6
dB
Receiver Specifications
Return Loss of Receiver
RL
12
dB
Received Power
-13.0
1.3
dBm (avg)
1
Operating Wavelength
λ
770
860
nm
Transmitter Specifications
Spectral Center Wavelength
λ
C
770
860
nm
Spectral Width
λ
4
nm (rms)
Launched Optical Power
PT
-7.0
-1.0
dBm (avg)
2
Optical Extinction Ratio
6
dB
3
Relative Intensity Noise
RIN
12
-116
dB/Hz
4
Eye Opening
57
% (pk-pk)
5
Deterministic Jitter
DJ
20
% (pk-pk)
6
1. The minimum and maximum values of the average received power in dBm give the input power range to maintain a BER < 10
-12
.
These values take into account power penalties caused by the use of a transmitter with a worst-case combination of transmitter
spectral width, extinction ratio, and pulse shape characteristics.
2. Launched optical power is measured at the end of a 2 meter section of a 50/125
μ
m fiber (N.A.=0.20) for the IBM42M10SCYAA10
(short wavelength GLM) and a 9/125
μ
m fiber for the IBM42M10LCYAA20 (long wavelength GLM). The maximum and minimum of
the allowed range of average transmitter power coupled into the fiber are worst case values to account for manufacturing vari-
ances, drift due to temperature variations, and aging effects.
3. 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 in the presence of worst case reflections.
4. RIN
12
is the laser noise, integrated over a specified bandwidth, measured relative to average optical power with 12dB return loss.
See ANSI Fibre Channel Specification Annex A.5 [1].
5. Eye opening is the portion of the bit time which is error free for a given bit error rate (BER). The Fibre Channel standard for BER is
<10
-12
. The general laser transmitter pulse shape characteristics are specified in the form of a mask of the transmitter eye dia-
gram. These characteristics include rise time, fall time, pulse overshoot, pulse undershoot, and ringing, all of which should be con-
trolled to prevent excessive degradation of the receiver sensitivity. When assessing the transmit signal, it is important to consider
not only the eye opening, but also the overshoot and undershoot limitations.
6. Deterministic Jitter is measured as the peak-to-peak timing variation of the 50% optical signal crossings when transmitting repeti-
tive K28.5 characters. It is defined in FC-PH, version 4.1, clause 3.1.84 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 depen-
dent jitter (DDJ) caused by the interaction of the limited bandwidth of the transmission system components and the sym-
bol sequence.