DP-QPSK Hybrid, Kylia COH28, 90 Deg. Optical Dual Polarization Hybrid
To be used for optical coherent detection such as DP-QPSK receivers, Kylia’s ten-port 2×8 Coherent Mixer (aka QPSK mixer) combines the incoming signal with a local oscillator to generate eight light states in the complex-field space. The eight light output signals can then be coupled into four pairs of balanced detectors. The block diagram below shows the application of a 2×8 coherent mixer in a DP-QPSK receiver. Since the mixing process is data rate independent, the devices can be used for any data rate in applications such as 40Gb/s or 100Gb/s transmission systems.
The COH28 and COH28-X are based on two single polarization 90° optical hybrids that enable to extract phase, amplitude and polarization from a signal with any polarization. The COH28-X is a new generation optical hybrid with improved performances (among other things, a wider operating wavelength range and much better dual uniformities).
These products are purely passive and athermal.
The COH28-X also feature a phase tunability option in order to perfectly adjust the 90° of the hybrid depending on the wavelength used. Kylia also offers a dual polarization 180° hybrid named COH22.
Key Features and Benefits
- Purely passive (no temperature control)
- Low insertion loss, Low phase error, <1ps skew
- Colorless (wavelength independent)
- Data-rate independent
- Compact size
Applications
- Optical coherent detection
- DP-QPSK demodulation
- Transmission at 100Gb/s, 200Gbps or 400Gbps (preferred choice of modulation format)

