Silicon Mach-Zehnder Modulator With SOA for High-Bandwidth Output
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Solution Overview
Problem
Existing Mach-Zehnder modulators face limitations in performance, particularly in bandwidth and extinction ratio, when operating at a quadrature point, which also leads to increased power consumption and reduced optical modulation amplitude.
Innovation Solution
A photonic chip with a Mach-Zehnder modulator using silicon technology, featuring reduced modulation section lengths and integrated semiconductor optical amplifiers (SOA) to adjust the operating point between 0.6*pi and 0.9*pi, combined with control mechanisms to optimize phase shift and optical gain, thereby enhancing bandwidth and extinction ratio while reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the Mach-Zehnder modulator operates at a quadrature point (set phase shift = pi/2), then the output intensity modulation is linearized, but the bandwidth and extinction ratio are limited and power consumption increases
Solution Approach 1:
The patent changes the operating point parameter from the conventional quadrature point (pi/2) to a new range (0.6*pi to 0.9*pi). This parameter change enables simultaneous achievement of high bandwidth (>60 GHz), high extinction ratio (>20 dB), and reduced power consumption while maintaining sufficient modulation linearity through the specific phase shift range optimization
2Productivity
If the modulation section length L is reduced to increase bandwidth, then the bandwidth exceeds 60 GHz, but the optical modulation amplitude decreases and power consumption increases
Solution Approach 1:
The patent introduces a semiconductor optical amplifier (SOA) as an intermediary component placed after the Mach-Zehnder modulator. The SOA compensates for the optical modulation amplitude loss caused by reduced modulation section length, enabling short-length modulation sections (L < 3 mm) to achieve high bandwidth (>60 GHz) while the SOA restores the optical signal strength, thereby reducing the need for high input power and lowering overall power consumption
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves a bandwidth exceeding 60 GHz, maintains a sufficient extinction ratio, and lowers power consumption by integrating a low-gain SOA, ensuring efficient optical modulation with improved performance characteristics.
Implementation Method 1
a semiconductor optical amplifier formed on and/or in the useful layer and arranged downstream of the Mach-Zehnder modulator output, said semiconductor optical amplifier being configured to amplify a signal modulated by the Mach-Zehnder modulator
Implementation Method 2
the first adjustment means comprises a first heating element configured to locally modify, by heating, the refractive index of either the first branch or the second branch in order to impose the set phase shift F
Data Source
AI summary
The invention relates to a photonic system provided with a photonic chip made in silicon technology, said photonic chip (10) comprising:—a Mach-Zehnder modulator (100) the modulation sections (105, 106) of which extend over a length L smaller than 3 mm;—first means (107) for adjusting operating point;—a semiconductor optical amplifier (SOA) configured to amplify a signal modulated by the Mach-Zehnder modulator, the semiconductor optical amplifier (SOA) being such that the amplitude of optical modulation associated with the photonic chip, when the set phase shift F is adjusted to the range 0.6*pi-0.9*pi, is of between −2 dBm and 6 dBm, at an output port S placed downstream of the semiconductor optical amplifier (SOA).