Data Sheet

8

Pin Definitions

Pin1 MZ data DC Bias input and Pin 2 MZ data-bar

DC Bias input.

DC bias voltages for data and data-bar MZ arms. These pins

must be connected to a low noise negative DC voltage,

typically around -2V (WRT case). These voltages are defined

for each Tx in the deliverable data. A precision voltage source

must be used, which is capable of sourcing up to 10mA to

each pin. Refer to Bookham applications note AN0130 for

circuit implementation and filtering suggestions.

Pin 3 VOA control pin.

VOA control pin. A negative DC voltage (WRT case) between

0V to -8V is applied to pin 3 to control the Variable Optical

Attenuator (VOA). The VOA is used in a control loop with a

power monitor to provide continuous optical power out of the

optical fiber. Refer to Bookham applications document

AN0132 for information.

Pin 4 Power tap pin.

The power tap pin must be biased at -5V (WRT case).

The supply should be regulated if the device is to be used

in mode1 or mode 2 as the monitor diode responsivity is

voltage dependent. Refer to Bookham applications note

AN0132 and AN0143 for information.

Pin 5, 7 and 9 Ground.

Package ground connections.

Pin 6 MZ Data-bar modulation input and Pin 8 MZ Data

modulation input.

Operation is typically using differential electrical drive voltages

applied to both the Data and Data-bar MZ modulator inputs.

AC RF coupling must be used.

Pin 10 TEC(-) and Pin 11 TEC(+).

The LMC10 contains a Peltier heatpump. Applying a negative

voltage on Pin 10 with respect to Pin 11 will cause the

internal optics to be cooled relative to the case temperature.

Reversing the applied voltage will cause the internal structure

to be heated. The heatpump must be used in a feedback

controlled circuit in conjunction with the internal thermistor.

Pin 12 Laser Anode.

The laser is operated with a forward bias current, the laser

cathode being connected internally to case ground.

Pin 13 Thermistor.

The thermistor is used in the TEC control loop for keeping the

internal temperature at a constant value. It has a nominal

resistance of 10k Ohms at the typical operating temperature

of 25ºC and is not polarity sensitive, although one side of the

thermistor is connected to package ground. Operating

current should be limited to less than 100µA to prevent self

heating errors. The exact thermistor value is supplied with

each Tx as part of the deliverable test data to ensure the

correct operating wavelength.

Pin 14 Back Facet Monitor Diode Anode (Etalon).

The signal from this photodiode carries the spectral response

of the wavelength filter.

Pin 15 Back Facet Monitor Diode Common Cathode.

Common connection for the monitor diode cathodes.

Pin 16 Back Facet Monitor Diode Anode (Reference).

The signal from this photodiode is the reference signal and

indicates the power emitted from the rear facet of the laser.

The signal from the reference and etalon monitors are used in

a control loop to maintain the wavelength of the laser at the

defined lock point.