HFE4192-58x Product Specification – Apr 2013 F i n i s a r
Confidential and Proprietary © 2012 Finisar Corporation. All rights reserved Rev. A1 Page 4
Notes:
1) Reliability is a function of temperature, see www.adopco.com for details.
2) For the purpose of these tests, I
F
is DC current.
3) Threshold current varies as (T
A
– T
O
)
2
. It may either increase or decrease with temperature, depending
upon relationship of T
A
to T
O
. The magnitude of the change is proportional to the threshold at T
O
.
4) Slope efficiency is defined as ΔP
O
/ΔI
F
.
5) To compute the value of Slope Efficiency at a temperature T, use the following equation:
η(T) ≈ η(25
o
C)*[1+(Δη/Δ T)*(T-25)]
6) Rise and fall times specifications are the 20% - 80%. Most of the devices will measure <80ps fall time.
7) To compute the value of Series Resistance at a temperature T, use the following equation:
R
S
(T) ≈ R
S
(25
o
C)*[1+(ΔR
S
/ ΔT)*(T-25)]
8) These specifications are for the TOSA component alone. Reflections introduced by any subsequent
higher level assembly may affect these values.
9) Monitor current tracking is defined as follows:
10) Relaxation Oscillation Frequency (ROF) is determined by the relationship:
2
t
r
2
τ
c
t
1r
2π
1
ROF −
⋅
−
⋅=
Where r= I
F
/I
TH
, t
c
is the photon lifetime (2.5ps), and τ
2
is the spontaneous emission lifetime (1ns).
Both t
c
and τ
2
are functions of temperature. When operating at high temperature, the r (I
F
/I
TH
) value
can be significantly reduced and still maintain adequate speed performance. This is recommended in
order to preserve reliability.
III. Typical Performance Curves
Emitted Power vs. Current: Power varies approximately
linearly with current above threshold.
Threshold Current vs. Temperature: Threshold
current varies parabolically with temperature; thus it can
be nearly constant for a limited temperature range.
Temperature
Threshold Current
T
MIN
, I
MIN
I
TH
≈
I
MIN
[1.1×10
-4
(T-T
MIN
)
2
+1]
0.45mW / 0.45mW) (PI
0.75mW / 0.75mW) (PI
Deltrk
OPD
OPD
=
=
=
rr
n
Pmax
Typical operating current / power
I
th
η
