Generalized Mach–Zehnder interferometer architectures for radio frequency translation and multiplication: Suppression of unwanted harmonics by design

A full‐duplex dual‐polarization QPSK in a digital radio‐over‐fiber system

“…However, the approximations to the propagation constants can be used to solve the mode propagation and therefore, the MMIs are named as nonideal. Referring to an earlier work, in such a case, the main parameters of interest are the power imbalance and the phase errors at the output of the MMIs. Although the matter may be relevant from the computation time viewpoint, its effect in the present work is negligible because the width of the simulated structure is in the tens of micrometers range and the number of simulated modes in both ideal and nonideal is significantly large.…”

“…An identical replica of the MPIC is used afterwards as an IQ modulator for the baseband information signal. The optical signal was modulated with an I and Q baseband 25 Gbps non-return-to-zero 2 15 -1 pseudo random binary signal (PRBS). Both modulated and unmodulated singlesidebands of each polarization are passively combined, and both polarizations are multiplexed via polarization beam combiner (PBC).…”

“…Since coherent RoF systems have been implemented based on DSP algorithms which are well known from high capacity baseband systems, one of the main challenges in RoF systems is generation and distribution of mm‐wave RoF signals. Several possible methods of generation and distribution of mm‐wave RoF signals have been proposed, and widely used (eg, the heterodyne mixing of two correlated and spatially separated harmonics). A system has been recently proposed and numerically demonstrated in, where the microwave photonics integrated circuit (MPIC) is used for three roles; (i) spatially‐separated carrier generation for remote heterodyning, (ii) IQ‐modulation in the downlink (iii) up‐conversion in the uplink.…”

Dual-function photonic integrated circuit for frequency octo-tupling or single-side-band modulation

“…The difference between the circuits proposed have largely concerned variations of the static optical and electrical phase shifts required or the implementation of an equivalent circuit using standard Mach-Zehnder modulators (MZM) rather than individual phase-modulators (PM) as the basic building brick. It has been shown in recent works [10][11][12] how to use the intrinsic phase relations between the ports of splitters and combiners and specifically multi-mode interference (MMI) couplers to implement substantially the static optical phase shifts required by these circuits, thereby avoiding the need to apply static DC bias to the electrooptic modulators and the associated drift issues that otherwise require complex stabilization circuitry [13,14]. The aim of this Letter is to show that relatively minor modifications or additions to a particular circuit in the generalized MZM class [11] may enable the reuse of much of the circuit for distinct applications, heralding the prospect of a first-general purpose microwave photonic integrated circuit.…”

A generalized circuit architecture for RF-photonic frequency multiplication with minimum RF energy

“…where N is the number of MZM stages. As a proof of the concept, the general architecture is illustrated by an example of frequency sex-tupling by a three MZM stages in cascade (N = 3) and compared with a functionally equivalent parallel MZM structure [17]. The intrinsic conversion efficiency of the sex-tupling circuit is found to be 5 dB greater than the fully parallel architecture.…”