DS-7059 Rev 00
Jan 2014

EM750 Narrow-Linewidth DFB Laser ModuleFeatures
 Narrow Linewidth Low RIN High Power Tunable Pin-Compatible with EM650
 Custom 50 GHz ITU Grid Wavelengths AvailableApplications
 Sensors
 Spectroscopy Analog Communications
 LIDAR

General Description
The Gooch and Housego EM750 represents a new generation of OEM narrow-linewidth lasers. It is based on the EM650 family of
integrated DFB lasers known for their ultra-low noise, stability, and tunability. The new EM750 combines these traits with a patentpending mechanism that retains the advantages of the EM650, but reduces the linewidth to a typical value of <10 kHz. Laser phasenoise is significantly reduced for Fourier frequencies below ~15MHz, providing considerable improvements in performance for many
linewidth-sensitive applications. The Relative Intensity Noise (RIN) of the EM750 is below -140dBc/Hz between 10 kHz and 40 GHz,
making it suitable for the most demanding analog applications. The EM750 is also widely tunable, making it well suited for highresolution laser spectroscopy.

Absolute Maximum Ratings
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only and operation of the device at these or conditions beyond these is not implied. Exposure to absolute maximum ratings forextended periods of time may affect device reliability.
ParameterSym.

Storage Temperature
Operating Case Temperature

MinMax

Unit

TSTG
TOP

-40-10+85+65

C
C

Voltage Supply

Vcc

4.6

5.5

VCurrent Supply
Laser Enable Input Voltage
Laser Enable Input Current
Power Adjust Input Voltage
Power Adjust Input Current
Temperature Adjust Input Voltage
Temperature Adjust Input Current
Monitor Detector Output Voltage
Monitor Detector Output Current
1Optical Output PowerIcc
LEILE
Vpa

3.5
Vcc+0.32
3.4+3.5
5+3.5
Vcc
+15
1.1*Pbol

AV
mA
V
mA
V
mA
V
mA
mW

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Vta

Condition

GND-0.3
Warning: see notes
Warning: see notes
Warning: see notes
Warning: see notes

Vmon
Imon
Pop0-3.5
0-3.5-15Pbol

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Page 1 of 7

DS-7059 Rev 00Jan 2014

EM750 Narrow-Linewidth DFB Laser Module
Optical Characteristics
2

Tamb=25C baseplate temperature, continuous wave, and beginning of life (bol ) unless otherwise specified. All parameters measured
after 60s settling time. Vcc = LE = 5.0V with PA and TA open.
Parameter

Sym.

Optical Output Power Setpoint

Pop

Optical Frequency Setpoint Accuracy

Fop

Tamb=25C

Optical Frequency Stability
3
Linewidth4
Relative Intensity Noise
5Side Mode Suppression
Optical Isolation

FoptΔν

P=PbolRINSMSR
ISOPolarization Extinction Ratio

PER

P=Pbol, peak value
P=PbolFopt within C-Bandw/ high quality patchcable

Power Adjust Tuning Coeff.
(Power, above threshold)
FOR REFERENCE ONLYPower Adjust Tuning Coeff.
(Wavelength, at operating point)
FOR REFERENCE ONLY
Temperature Tuning Coeff.
(Wavelength)
Guaranteed Mode-Hop Free Tuning
6RangeCondition

Min

Typ

30

35-5±2.5+5GHz

1510-150

2515-140MHzkHz
dBc/HzdB
dB

3045Max

Unit
mW

55

17dB

dP/dVpa

2.05V DC offset----+Pbol/2----mW/V

dλ/dVpa

2.05V DC offset-----100----

GHz/V

dλ/dVta

2.5V DC offset+58
Fopt-75

GHz/V

Fopt

Fopt+75

GHzElectrical Characteristics
All voltages in this document are taken at the device pins, referenced to GND at the device pins, unless otherwise mentioned.
ParameterSym.

Voltage Supply
7
Current Supply
Laser Enable High
Laser Enable Low
Laser Enable Input Impedance
8Laser Enable Bandwidth9Power Adjust

Vcc
Icc
LEH
LEL
ZLE
VPA

Warning: see notes

Power Adjust Input Impedance

ZPA

to 2V Vref1kΩ

-3dB

8kHz

Power Adjust Bandwidth
10Condition

MinTypMax

Unit

4.85

5.2
3.5

VAVVkΩHzV

3.5
1.55350Temperature Adjust
Temp Adjust Input Impedance

VTAZTA

Warning: see notes
To 2.5V Vref

1Monitor Detector Output

VMONat Pop

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Page 2 of 7

DS-7059 Rev 00
Jan 2014

EM750 Narrow-Linewidth DFB Laser Module
Fiber & Connector Characteristics
Parameter

Sym.

Condition

MinTypMax

UnitPM Panda Parallel
to slow axis

Fiber TypeCore Diameter
Connector KeyingConnector TypeParallel to slow axis

82.05mm keyway
FC/APCμm

Environmental Characteristics
All temperatures in this document are taken at the device baseplate unless otherwise mentioned.
ParameterSym.

Condition

MinTypMax

Unit

Storage TemperatureVcc-40+85⁰C
Operational Temperature
Icc-10+60⁰C
Humidity
noncondensing
Notes1) Output power should not be driven more than 10% beyond delivered operating point.
2) ”bol” references beginning of life, at as-delivered setpoints. Due to manufacturing tolerances, output power may be significantly above rated power.
3) Linewidth measured using 80 km delay, 10 kHz resolution bandwidth, 250 ms sweeptime averaged over 75 scans
4) RIN peak value determined using a 20pt moving average and a 2000 point sweep.
5) EM750 is screened for SMSR within 25MHz of line center during linewidth testing. Internal DFB is screened for SMSR via
wavelength meter.
6) Guaranteed mode-hop free range based on course tuning. Mode-hops in the range of 20Mhz are likely over long periods oftime.
7) Supply current limit should never be set below 3A, which could result in an undervoltage condition at startup, resulting in
erratic behavior and potential failure.
8) Please note that Laser Enable (LE) input has a slow response and is not intended for modulation of the laser. Modulation
should be performed using the PA input.
9) While the PA pin can be pulled to 3V, it should not be used to drive the laser beyond 110% of its BOL as-delivered power
setpoint. PA should be sequenced as described in EM4 DS-7047 EM650 Tuning App Note .
10) Temperature adjust (TA) allowable settings are dependent on ambient/heatsink conditions and laser output power. Careshould be used when adjusting the PA input as driving it too far can result in thermal runaway of the internal TEC anddamage or destruction of the device. TA should be sequenced with respect to the power supply as described in DS-7047
EM650 Tuning App Note and in Warnings section of this document.

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Page 3 of 7

DS-7059 Rev 00
Jan 2014

EM750 Narrow-Linewidth DFB Laser Module
Ordering Information
EM750-

FREQUE-

POW-FB-CON

Parameter

OptionDescription

Connector

FCA

FC/APC

FiberPM

PM (Panda) Fiber

Rated Output
Power03030mW Rated Output

OpticalFrequency

FFFFFF

Frequency in GHz leave as XXXXXX for
don’t care. Standard frequencies
range between 192000 and 196000
other frequencies available upon request

ProductFamily

EM750

Narrow-Linewidth DFB Laser Module

Pinout and Mechanical Drawing

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Page 4 of 7DS-7059 Rev 00
Jan 2014

EM750 Narrow-Linewidth DFB Laser Module

10KHz

Typical Linewidth

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DS-7059 Rev 00
Jan 2014

EM750 Narrow-Linewidth DFB Laser Module
WARNINGS: several of the parameters listed inthe specifications above are denoted with awarning. These warnings are covered by the following notes which should be understood before operating the device.

input to levels corresponding to the desired operating conditions of the laser module. The addition of a series resistor tothis input, which will increase laser current noise and linewidth, is not recommended. The safest method of driving
this input is with a tri-state output whose output is current
limited when active, maintained at high-impedance until Vcc
is established, and whose output returns to high-impedance
before VCC is removed. Damage due to overdrive will not
be covered under warranty. Use of this input will likely deMounting
crease the performance of the EM750 by bypassing its internal ulra-low noise voltage reference.
The EM750 is conductively cooled through its base andThe PA input must never be shorted directly to Vcc whichneeds to be mechanically clamped or bolted to a customer
would cause circuit malfunction or rapidly destroy the DFB
supplied heatsink using a thermal interface material. EM4laser.
recommends Panasonic PGS series pyrolitic graphite sheets,
available in the US from Digi-Key Corporation. Should PGS
Temperature Adjust (TA)not be available, a high-quality non-silicone heatsink grease
applied per the manufacturer’s instructions is an acceptable The EM750 is designed to operate the laser chip at a conalternative. Care should be taken to keep the base tempera- stant temperature holding the output frequency withinture of the module between -10 and 60C at all times during 5 GHz of the ordered frequency. However, some applicaoperation.
tions require coarse tuning of the output frequency via temperature. In these cases, the laser may be tuned using theNoise suppression
TA input. Temperature deviations of more than 8 degrees(100 GHz in laser frequency) from the as-ordered setpoint
The EM750 is a no-compromises low-noise integrated laser
may result in decreased stability and increases the likelihood
solution; the temperature controller output is class AB lineof the laser experiencing a longitudinal mode-hop. Thear, there are no DC/DC converters in the module, the lowest
achievable tuning range will depend on the specific laser
noise components and architectures available are used
chip, the ambient temperature, and the thermal resistancealong with heavy filtering. Nevertheless, power supply ripple
to the ambient. Use of this input carries the inherent potenand noise should be minimized and the cable shield should
tial of overdriving the TEC. The TA input is clamped to Vcc
be connected to the EM750 connector shield and tied to thethrough integrated protection diodes. If Vta is establishedappropriate signal at the power supply end of the cable.
before Vcc these clamp diodes will conduct. The input current should always be limited to ≤3.5mA to prevent destrucPower Adjust (PA)tion of the clamp diodes. The safest method of driving thisThe EM750 is designed to run in constant current mode with input is with a tri-state output whose output is current limthe drive current set for the as-ordered output power to ited when active, maintained at high-impedance until Vcc isachieve the highest possible performance. However, some established, and whose output returns to high-impedance
applications require fine tuning of the laser drive current to before Vcc is removed. The device warranty will not be honfine-tune frequency and power. The PA input provides this ored for lasers with overdriven TECs. Use of this input alsofunctionality, but its use carries an amount of risk. Use of carries the likelihood of decreased frequency stability as it
this input carries the potential to overdrive the laser and/or bypasses the internal ultra-low noise voltage reference.
circuitry with the ability to destroy or drastically reduce the The TA input must never be shorted directly to Vcc ordevice lifetime. No internal protections on this input are ground which would cause circuit malfunction or rapidly
provided, but the user is encouraged to clamp or otherwise destroy the DFB laser.
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Page 6 of 7

DS-7059 Rev 00
Jan 2014

EM750 Narrow-Linewidth DFB Laser ModuleGrounding
Care must be taken with grounding, cabling, and connections due to the amount of current the module consumes.
Make sure that the voltage on pins PA/TA reference groundas close to the EM750 as possible if either input is connected. DO NOT connect the cable shield to ground at both endsof the cable to avoid producing a ground loop. DO NOT connect the EM750 housing to ground to avoid producing aground loop. DO use large gauge and/or short wire runs tominimize power rail fluctuations due to drive current. If
your DC supply has remote sense lines, consider using themto control the voltage as close to the module pins as possible.

Applications Information
Be sure to check the EM4 website for the latest applications
information for this device. Application note DS-7047 covers
general usage of EM4’s integrated modules along with information particular to tuning via temperature or chirp. If
you plan to tune this device, it is highly recommended thatyou read this app note.

Startup Considerations
The EM750 consumes a considerable amount of current in
the startup phase and when operating at temperature extremes. A voltage source plus cabling able to deliver themaximum specified current at no less than the minimum
voltage is therefore needed. Current limiting below thespecified maximum during the startup phase will result in aninternally measured drive voltage lower than specified. Thiscondition can result in permanent, non-warrantable damage
to the device.
If the user fails to sequence the supplies as described in thePower and Temperature adjust sections of this document
and Applications Note DS-7047, the device will immediately suffer non-warrantable damage or destruction.

The component complies with all applicable portions of 21 CFR 1040.10, 21 CFR 1010.2 and 21 CFR 1010.3. Since this is a component, it does not comply with all of the requirements contained in 21 CFR 1040.10 and 21 CFR 1040.11 for complete laser products.
The information published in this datasheet is believed to be accurate and reliable. Gooch and Housego reserves the right to change
without notice including but not limited to the design, specification, form, fit or function relating to the product herein. ©2014
Gooch and Housego. All rights reserved.

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