The modulator group is developing InP based Modulators with a travelling wave electrode design. This electrical design approach is the key to achieve a 3 dB bandwidth beyond 50 GHz. Such high speed external modulators are the key components for metro and long haul fibre networks.

The Mach-Zehnder Modulator structure is suited not only for standard on-off-keying modulation, but also for enhanced new modulation schemes like Duobinary or Differential Phase Shift Keying (DPSK). The nested IQ Modulator structure is capable for the enhanced DQPSK modulation format. 

A 40 Gbit Modulator module has been developed with this component. Either GPPO or V-Connectors are used. 

Typical bandwidth of such a module is 40 GHz, the necessary driving voltage is V_pp = 2.5 V with an insertion loss of 8 dB.

Lowest drive voltage achieved for a 40 Gbit Modulator was V_pp = 1.5 V.

A variety of different modulators has been developed: 

• MZ Modulator for OOK
• MZ Modulator for DPSK, Duobinary
• IQ-Modulator for DQPSK
• Phase Modulators

All devices are completely fabricated at HHI using our InP processing line. The electro-optic RF-Response can be measured up to 67 GHz on chip and module level.