Optical Full-Field Transmitter with Integrated SOI Circulators
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Solution Overview
Problem
The limited performance of direct modulation/detection technology in optical networks restricts data rates per user, and existing coherent optical access network technologies are costly and have large footprints, limiting their scalability and efficiency in meeting increasing bandwidth demands.
Innovation Solution
An optical full-field transmitter (OFFT) using coherent optical injection-locking (COIL) with integrated optical circulators and phase modulators on a silicon-on-insulator (SOI) substrate, replacing bulky and expensive components with photonic integration to reduce cost and footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If coherent optical access network technology is used to meet high bandwidth demands, then data throughput and receiver sensitivity are improved, but device cost and footprint increase
Solution Approach 1:
The patent merges multiple optical components (circulator, phase modulator, Fabry-Perot laser) into a single integrated photonic circuit on a silicon substrate. This integration eliminates the need for separate bulky components, significantly reducing the overall device footprint and cost while maintaining coherent optical transmission capabilities for high data throughput
Solution Approach 2:
The integrated photonic circuit performs multiple functions within a single device: optical signal routing (circulator), phase modulation (phase modulator), and light generation (Fabry-Perot laser). This multi-functionality reduces the number of separate components needed, thereby reducing device footprint and cost while preserving coherent optical network performance
2Adaptability or versatility
If parallel Mach-Zehnder modulators are used for amplitude and phase modulation, then modulation capability is improved, but optical insertion loss and device complexity increase
Solution Approach 1:
The patent extracts and eliminates the parallel Mach-Zehnder modulator structure from the system. Instead, it uses a single phase modulator combined with direct modulation of the Fabry-Perot laser to achieve both amplitude and phase modulation. This extraction of the problematic component reduces optical insertion loss while maintaining modulation capability
Solution Approach 2:
The patent replaces expensive and lossy parallel Mach-Zehnder modulators with a more efficient combination of a single phase modulator and directly modulated laser. This substitution uses simpler, less lossy components to achieve the same modulation functions, reducing optical insertion loss and improving overall system efficiency
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 OFFT significantly reduces laser and modulator costs, optical insertion loss, and modulation loss, while enhancing data throughput and reducing device complexity and power consumption, making it suitable for high-capacity optical access networks.
Implementation Method 1
The optical circulator includes a plurality of silicon waveguides, a plurality of silicon ring resonators, a magneto-optic film, a magneto-optic garnet layer, and a plurality of metal strips
Data Source
AI summary
An optical full-field transmitter (OFFT) includes a plurality of optical circulators and a polarization beam combiner. The plurality of optical circulators are fabricated on a silicon-on-insulator (SOI) substrate, where each of the optical circulators has (a) a first port that optically couples to a high-quality optical source, (b) a second port that optically couples to a child laser configured to receive amplitude modulation data, and (c) a third port optically coupled to a phase modulator that (i) is configured to receive a phase modulation data and (ii) includes an output port that outputs amplitude and phase modulated light. The polarization beam combiner receives the amplitude and phase modulated light from each of the optical circulators and outputs combined amplitude and phase modulated light.