Baud-Rate Flexible Optical Transmitter With Sample Rate Converter
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Solution Overview
Problem
Existing optical communication systems face challenges in generating electrical signals at high data rates, such as 150 Gbit/s, 200 Gbit/s, and 250 Gbit/s, particularly in maintaining a stable sampling rate for coherent transmission systems, which is difficult with traditional transmitters.
Innovation Solution
A baud-rate flexible transmitter is developed, incorporating a sample rate converter that transforms digital electrical signals through Fourier and inverse Fourier transforms to achieve flexible sampling rates, allowing for spectral shaping and processing at various data rates using a fixed-sample-rate digital-to-analog converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional transmitters are used to generate electrical signals at high data rates, then signal transmission can be achieved, but maintaining a stable sampling rate becomes difficult
Solution Approach 1:
The transmitter employs a dynamic sampling rate conversion mechanism that adapts to different baud rates while maintaining stability. The sample rate converter dynamically adjusts the sampling rate based on the input signal characteristics, allowing the system to operate at various data rates (150 Gbit/s, 200 Gbit/s, 250 Gbit/s) while preserving sampling rate stability through real-time adaptation.
Solution Approach 2:
The system changes the sampling rate parameter dynamically to match different baud rates. By implementing a sample rate converter that transforms the sampling rate according to the input signal's baud rate, the system maintains optimal performance across varying data rates without compromising sampling rate stability.
2Adaptability or versatility
If flexible baud rates are implemented, then adaptability to different data rates is improved, but device complexity increases
Solution Approach 1:
The transmitter is designed with multi-functional components that can operate across multiple baud rates. The sample rate converter and digital-to-analog converter are configured to handle various data rates (150, 200, 250 Gbit/s) using the same hardware architecture, reducing overall system complexity while maintaining baud rate flexibility.
Solution Approach 2:
A sample rate converter is introduced as an intermediary component between the signal processing stages. This mediator transforms the sampling rate to match the desired baud rate, enabling flexible data rate adaptation without requiring completely different transmitter architectures for each rate.
3Speed
If high data rates are generated without proper sampling rate conversion, then transmission speed increases, but signal distortion occurs
Solution Approach 1:
The sample rate converter performs preliminary sampling rate adjustment before the digital-to-analog conversion stage. By pre-converting the sampling rate to match the target baud rate, the system prevents signal distortion from occurring during high-speed transmission, ensuring signal quality is maintained at data rates up to 250 Gbit/s.
Data Source
AI summary
An optical transmitter may include a sample rate converter and a digital-to-analog converter operable to convert an inputted digital electrical signal to an analog optical signal. The signal converter may include a first interface operable to receive a digital electrical signal that may include a block of input data having N symbols in a time domain. The signal converter may also include: a first module operable to transform, via a Fourier Transform, the input data having N symbols from the time domain to a frequency domain; a second module operable to up-sample the N frequency domain samples so that there are 1.6N, 2N, or 2.67N frequency domain samples, for example; and then a third module operable to transform, via an inverse Fourier Transform, the 1.6N, 2N, or 2.67N frequency domain samples to an equivalent number of time domain samples at 1.6, 2.0, or 2.67 samples per symbol, respectively.