Ultra Linear RF Amplifier (32G QAM, OFDM)

In high speed optical communications most amplifiers are optimized for the amplification of binary bit sequences. In some applications, however, multilevel signals (e.g. as driving signals for optical QAM or PAM) or even analog signals (e.g. for optical OFDM) need to be amplified to drive the external modulator. These applications require the amplifier to have an even higher emphasis on the following parameters:

  • High Bandwidth (fast rise and fall times)
  • Minimum over- and undershoot (ringing)
  • Bessel-roll-off characteristic in frequency response for linear phase
  • High linear output power (high first order compression, P1dB & third order intercept point, IP3) to maintain a linear drive for a given modulator Vπ

A illustration of how these parameters affect the signal quality is exemplarily shown here.

The SHF S807, in particular, is an amplifier specifically designed for 4-level signals.

Below you will find a selection of SHF amplifiers with different gain and output drive to suit different input signal conditions and output amplitude to suit different modulator drive requirement for such complex signal generation. To judge linearity and characteristic of the individual amplifier, the 1dB & 3dB compression point and the third order intercept point are listed.

 

Type
Min. Bandwidth
Typ. Gain
Min. P1dB
Min. P3dB
Min. IP3
Datasheet

SHF 827

50 kHz - 65 GHz

10 dB

12 dBm
(2.5 Vpp)

16 dBm
(4 Vpp)

25 dBm

Datasheet SHF 827

SHF 803P

35 kHz - 40 GHz

17 dB

20 dBm
(6.3 Vpp)

22 dBm
(7.8 Vpp)

30 dBm

Datasheet

SHF S807

60 kHz - 50 GHz

24 dB

15 dBm
(3.5 Vpp)

18 dBm
(5 Vpp)

28 dBm

Datasheet SHF 807

SHF 806 E

40 kHz - 38 GHz

26 dB

20 dBm
(6.3 Vpp)

22 dBm
(7.8 Vpp)

33 dBm

Datasheet

 

The SHF 100BP amplifier can be specially tuned for multi-level operation (option ML).  This enables the device to perfectly amplify signals of up to 8 levels at data rates of more than 10 Gbps. An ideal source to drive this amplifier could be one of SHF’s digital-to-analog converters (DACs)

Type
Min. Bandwidth
Typ. Gain
Min. P1dB
Min. P3dB
Min. IP3
Datasheet

SHF 100BP Opt. ML

35 kHz - 14 GHz (typ.)

17 dB

21 dBm
(7 Vpp)

22 dBm
(8 Vpp)

36 dBm

Sorry, no data sheet available