SHF Communication Technologies AG
Wilhelm-von-Siemens-Str. 23D • 12277 Berlin • Germany
Phone ++49 30 / 772 05 10 • Fax ++49 30 / 753 10 78
E-Mail: sales@shf.de • Web: http://www.shf.deDatasheet
SHF 46213C
Optical DQPSK Transmitter

SHF reserves the right to change specifications and design without notice – SHF 46213C V002 – 2/May/2011

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Description
The SHF 46213C is an optical DQPSK transmitter unit. It is a field replaceable plug-in module whichneeds to be installed in a mainframe type SHF 10001B or SHF 10000A. Together with other plug-inmodules from this instruments series, a modular and scalable measurement system can be put together.
In a DQPSK (Differential Quadrature Phase Shift Keying) transmission system, the data is transmitted in
the differential optical phase change between the symbols. The data is encoded in four different phasestates. Since one transmitted symbol includes the information of two bits the symbol rate is reduced by
the factor ½. Therefore one advantage of a DQPSK transmission system is a high spectral efficiency.
The SHF 46213C uses a parallel modulator which converts 2 electrical data streams (I and Q) of up to 32
Gbps into 1 optical data stream of up to 32 GSymbols/s. Both electrical data streams modulate the lightby a thermally stable Chirp-free Lithium Niobate Mach-Zehnder modulator with a phase difference of π/2.
Before superposition of the two light streams the Q part gets π/2 shifted in order to have four different
phase states in the transmitted signal.

The 2 data channels can be switched On and Off independently, thus permitting to generate either DPSKor DQPSK signals.
To detect and to demodulate either the I or the Q channel, the 28 Gbps DPSK optical receiver SHF 47215
is the ideal instrument. It is possible to switch between the I and the Q channel for eye analysis or BER
measurement of both channels separately.
For a 32 Gbps BER measurement the SHF Bit Pattern Generators (SHF 12103) can provide the precoded I and Q data streams.
For the RZ modes, an amplified clock signal drives a third modulator. The output from this modulator is a
train of pulses of constant width. For the NRZ-D(Q)PSK modes, the third modulator is biased to allow lightthrough continuously.
The temperature stable modulators and an automatic bias circuit for both the DQPSK and pulse carver
modulators ensure high stability of the output signal.

Features•

32 GSymbol/s optical data streams•

Separate analysis of I and Q channel possible•

Quick optimization of optical eye diagram performance by user adjustable modulator bias control•

All features computer controlled•

All modulators’ bias conditions controlled automatically•

Selectable automatic and manual bias control (ABC circuit)

SHF reserves the right to change specifications and design without notice – SHF 46213C V002 – 2/May/2011

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Functional block diagramuC Control

Data modulator

Pulse modulator

ϕMZ

MZ
MZ
Data drivers

Pulse driver
Delayline

CW Light inClock inAB
Data inModulated
Light out

Specifications – SHF 46213C
Parameter

Unit

Min.

Typ.

Max.

Comment

Optical parameters
Wavelength range

C- and L-band

Insertion lossdB

12

DC Extinction ratiodB

20

Return lossdB

30

17connector to connector,
maximum transmission
without modulation

without optical connector

Electrical and electro-optical parameters
Electro-optical bandwidth ofData modulator

GHzSymbol rate
RZ-DQPSKDQPSKDrive amplifier electrical return loss
DataClock pulse RZ
Drive amplifier input level
Data input
RZ clock input
Dynamic signal to noise ratio
DPSK-mode, either Data A or B

Gsym/s-3dB electrical

25

20
5

32
32

dB
-10-10
Vpp
0.5
0.5
120.9
1.2
15

measured withSHF 47211
DPSK-receiver.
@ 20Gbps

SHF reserves the right to change specifications and design without notice – SHF 46213C V002 – 2/May/2011

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Absolute maximum ratings
Parameter

Unit

Min.

Typ.

Max.

Conditions

Optical input powerdBm

16

NRZ data amplifier input powerdBm

4

NRZ data

RZ clock driver input power

dBm

4

CW

General specifications
Parameter

1UnitMin.

Typ.

Weightkg

3.3

Dimensions

mm

59x213x450

Power consumption

W

20.5

Operating temperature°C

10Max.

Conditions
w/o Frontpanel Connectors

35

Electrical data input connectors

male K (2.92mm)

Clock input connector

male K (2.92mm)

Optical connectors

FC/PC

1

Other connectors available on request.

SHF reserves the right to change specifications and design without notice – SHF 46213C V002 – 2/May/2011

Page 4/5Test Measurements
The following equipment was used in obtaining these results:
31SHF12100 A Pattern Generator at 21.4 Gbps, PRBS 2 -1
SHF 1550DFB Laser source set to 15mW output power @ 1550 nm.
AMPAQ EDFA + bandpass filter
Agilent 86100A DCA with 70GHz plugin and precision timebase module
D(Q)PSK signals detected with SHF 47211 21.4 GBit/s DPSK receiver
only Data A switched ON

only Data B switched ON

S/N: 16

S/N: 16

Both Data A and Data B channel switched ON(DQPSK), 21.4 GSymbols/s:

S/N: 12RZ-DQPSKCSRZ-DQPSKS/N: 16

S/N: 16

SHF reserves the right to change specifications and design without notice – SHF 46213C V002 – 2/May/2011

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