Emcore’s Model 755M is a directly modulated (DM) DWDM optical
transmitter specifically designed for wideband applications that require
both CATV and DBS signals to be carried over up to 20 km of fiber. This
facilitates networks designs that may use a single transmitter to carry
multiple signals.
The 755M supports full 79-channel NTSC analog signal and or a
combination of QAM, DBS with reduced channel analog CATV. The
fiber length the 755M can support is up to 20km.
The 755M family of transmitter products is designed to support various
CATV transmitter applications with a common platform. A 75Ω CATV RF
video input supports frequencies up to 1002 MHz. Integrated within the
transmitter design are Emcore’s low chirp control, noise suppression
circuitry, and patented predistortion technology to provide outstanding
performance with any of Emcore’s wide range of cooled broadband
lasers. A second 75Ω RF input supports frequencies up to 2600 MHz for
FTTP, L-Band satellite, and wireless applications.
Performance Highlights
Min
Operating Temperature Range
Wavelength (100 GHz ITU Options)
Optical Power
Frequency Response (75Ω CATV Port)
(75Ω L-Band Port)
CNR
CSO
CTB
C/I (3 order, 950 – 2600 MHz)
SBS Suppression Capability
(Channel Option 11J & 57J only)
rd
Applications
Video signal distribution to
HFC CATV and FTTP nodes
Supports CATV, QAM, and
1527
DBS signal carriage
Replacement for externally
modulated transmitters
Features
Dual redundant power
supplies
SNMP network interface
Dual RF inputs for CATV and
DBS
Available on 100 GHz spaced
ITU DWDM C-band channels
Optimized RF integration of
predistorter, amplifiers, and
laser
Complete, efficient laser bias
and TEC control circuitry
OEM/ODM opportunities
available through Emcore
RoHS
Typ
25
-
-
-
-
-
-
-
-
-
Max
50
1560
-
1002
2600
-
-60
-65
-60
18
Units
°C
nm
dBm
MHz
dB
dBc
dBc
dBc
dBm
0
1530
10
47
950
51
-
-
-
-
Noise and distortion performance above assumes 79 channel NTSC loading with no QAM, 0 dBm
received optical power, 20 km SMF-28 fiber or equivalent. See following pages for complete
specifications and operating/test conditions.
For more information on this and other products:
Contact Sales at Emcore 626-293-3400, or visit www.emcore.com.
Model 755M Optical Transmitter
DATASHEET| AUGUST 6, 2008
Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings can cause permanent damage to the transmitter. These
are absolute stress ratings only. Functional operation of the device is not implied or guaranteed at these or any
other conditions in excess of those given in the operational sections of the data sheet. Exposure to absolute
maximum ratings for extended periods can adversely affect device reliability.
Parameter
Storage Temperature (power off)
75Ω CATV RF Input Level
Manual Mode
AGC Mode
L-Band RF Input Level
AC Input Range
AC Input Frequency Range
Power Consumption
-
-
V
AC
f
AC
P
Symbol
T
stg
Min
-40
-
-
-
-
94
50
-
Max
85
-10
-5
+15
250
60
50
Unit
°
C
dBm
dBm
V
AC
Hz
W
Optical Characteristics
Parameter
Optical Output Power
SBS Threshold
Wavelength
Side Mode Suppression Ratio
Optical Return Loss
1
Condition
-
For RF input option 11J and
57J only
-
-
APC style connector
Min
10
-
Typ
-
-
See table
Max
-
18
Unit
dBm
dBm
nm
30
40
-
-
-
-
dB
dB
1. In order to prevent reflection-induced distortion, the laser must be connected to an optical cable having a return loss of at least 55 dB for discrete
reflections and 30 dB for distributed reflections.
EMCORE CORPORATION
2
Model 755M Optical Transmitter
DATASHEET| AUGUST 6, 2008
RF Characteristics
The following specifications are reference at 25C. The test receiver responsivity of 0.95 A/W (at 1550 nm) and an
equivalent noise current of 7pA/rt(Hz). Test fiber is single mode, Corning SMF-28 (or equivalent) with 0.25 dB/km
maximum loss (at 1550 nm). In order to prevent reflection-induced distortion, the transmitter subassembly must be
connected to an optical cable with discrete reflections < -55 dB and distributed reflections < -30 dB.
PARAMETER
Operating Temperature Range
CATV Response Flatness
Test Port Response Flatness
CATV Input Return Loss
Test Port Return Loss
RF Test Point Level
CATV RF input power detection range
SYMBOL
T
op
S
21-CATV
S
21-TP
S
11-CATV
S
11-TP
P
out-TP-CATV
-
-
S
21-Lband
S
11-LBand
P
in-LBand
CONDITIONS
-
47MHz - 1002MHz,
Peak to Valley
Relative to 75 Ohm Input
47 MHz – 1002 MHz, 75Ω
47 MHz – 1002 MHz, 75Ω
Relative to 75 Ohm
Input Level
Note 1
Perform to specification
950MHz – 2600 MHz,
Peak to valley
950MHz – 2600 MHz
-
F1=2000MHz, F2=2000.5MHz
2-tone @ -3dBm/tone
Rx Opt Power = 0dBm
CATV Input with Loading specified
in CATV 75Ω Input Option
MIN
0
-
-1
16
16
-21
-20
-3
-
16
-0.5
TYP
-
-
-
-
-
-20
-
MAX
50
1.5
1
-
-
-19
-9.7
+3
UNIT
°C
dB
dB
dB
dB
dBm
dBm
dB
dB
dB
dBm
AGC Range
L-Band Response Flatness
L-Band Return Loss
L-Band Input Level
-
-
0
3.5
-
+0.5
L-Band Input C/I (3 Order)
rd
-
-
-60
dBc
1.
Detects RF power of CATV input port only. The total input power is defined in section 3.10 and 3.11. The input RF power detector
can handle the input power range between +5 to –10dB range from the nominal input power level.
EMCORE CORPORATION
3
Model 755M Optical Transmitter
DATASHEET| AUGUST 6, 2008
755M, Noise and Distortion Characteristics for CATV Input
CATV 75Ω Input Option
Ω
79ch NTSC
(4)
RF Level/ch
(dBmV)
15
Composite
(dBm)
-14.77
-13.84
-14.77
-14.77
-14.77
-14.70
-14.76
BER
-
10
-
-
-
-
-
(5)
CNR
(dB)
51
(1,2)
CSO
(dBc)
-60
-60
-60
-60
-60
-60
-60
(1,3,6)
CTB
(dBc)
-65
-65
-65
-65
-65
-65
-65
(1,3,6)
79ch NTSC + 75ch QAM @ -6dB
110ch NTSC
(4)
(4)
(4)
79ch = 15
75ch QAM = 9
13.57
17.75
16.2
(7)
-7
49
48.5
52
52
46
46
42ch CENELEC
60ch PAL
(4)
JCTEA: 57ch Analog + 40ch QAM @ -10dB
JCTEA: 11ch + 80ch QAM @ -10dB
1.
2.
3.
4.
5.
6.
7.
8.
(8)
57ch = 16.2
40ch QAM = 6.2
11ch = 21.2
80ch QAM = 11.2
Test with 3m and 20km of SMF28 fiber.
CNR may degrade
up
to 0.5dB over the operating temperature range.
CSO and CTB may degrade up to 1.5dB over the temperature range.
Test with 0 dBm received optical power.
QAM format = 256-QAM, ITU-T J.83 Annex C, Analog channels are modulated.
L-band input is injected with 2 tones, F1 = 2000MHz, F2 = 2000.5MHz with –3dBm/tone.
Test with EDFA,
–6dBm
received optical power, QAM format = 64-QAM. 2 tones, F1 = 2000MHz, F2 = 2000.5MHz,
applied to L-Band port with –3dB/tone. 18dBm launch power.
Test with EDFA,
–8dBm
received optical power, QAM format = 64-QAM. 2 tones, F1 = 2000MHz, F2 = 2000.5MHz,
applied to L-Band port with –3dB/tone. 18dBm launch power.
1. Introduction
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