DIN EN 62802:2018 pdf free.Measurement methods of a half-wavelength voltage and a chirp parameter for Mach-Zehnder optical modulators in high-frequency radio on fibre (RoF) Systems (IEC 62802:2017).
4 Electro-optic material-based Mach-Zehnder optical modulators 4.1 Mach-Zehnder optical modulators 4.1.1 Component parts The optical modulators and their modules consist of the basic parts as follows: — Mach-Zehnder interferometer type optical modulator; — input and output fibre pigtails (where appropriate); — bias control port (where appropriate); — photodiode for bias monitoring (where appropriate); — laser diode for light source (where appropriate); — thermal sensor (where appropriate); — Peltier element (where appropriate). 4.1.2 Structure
The structure is as follows: — electrode: lumped type, traveling-wave type, etc. — options: optical isolator, photodiode, half-mirror, laser-diode, etc.
Due to the Pockels effect, optical phase retardation at each arm in the Mach-Zehnder interferometer can be controlled by the voltage applied on the electrode. The optical phase retardations at the upper arm and the lower arm are proportional to the voltages V1 and V2 (see Figure 2).
4.2 Requirements for MZMs
4.2.1 General This method is based on the theoretical transfer curve of electro-optic material based Mach-Zehnder interferometer, where the phase shift of traveling light on each arm of the interferometer should be proportional to applied voltage, and the power of traveling lightwaves in each arm are almost the same. Requirements for the modulator of this measurement method are as follows.
4.2.2 Substrate material The main substrate materials of the modulator should be materials such as LiNbO3, LiTaO3, KH2PO4, PZT, PLZT, lnP, GaAs, lnGaAs, InAlAs, lnGaAsP, nonlinear optical chromophore containing polymer, FTC type chromophore containing polymer, etc., which realise the electro-optic effect (Pockels effect). If strictly considered, semiconductor materials do not possess a pure electro optic effect, however, the semiconductor Mach-Zehnder modulators can be adjudged as electro-optic material-based Mach-Zehnder modulators.
4.2.3 Optical waveguide design
The optical waveguide should be designed as a single Mach-Zehnder interferometer type comprised of two Y-junctions or symmetric directional couplers and parallel waveguides. Reflection-type Mach-Zehnder optical modulators are modified designs of the modulators.DIN EN 62802 pdf download.