Optical Coherent Transceiver Tunable Filter Passband Adjustment
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Solution Overview
Problem
Conventional optical coherent transceivers face challenges in handling high bit rates due to increased waveform distortion and the need for high-output optical amplifiers, which are difficult to integrate due to thermal design issues and size constraints, especially when trying to maintain signal quality and reduce noise.
Innovation Solution
The optical coherent transceiver incorporates a tunable filter on the input stage of the receiver, using auto level control to amplify reception light with a single wavelength, eliminating the need for high-output optical amplifiers and reducing power consumption by optimizing the passband adjustment based on detected signal levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-output optical amplifiers are used to maintain signal quality at high bit rates, then signal quality is improved, but device size and thermal design complexity increase
Solution Approach 1:
The optical amplification function is segmented into multiple distributed Raman amplification sections along the optical fiber transmission path, replacing the conventional single high-output amplifier. This distributes the amplification gain across multiple segments, reducing the output power requirement of each individual amplifier while maintaining overall signal quality.
Solution Approach 2:
Distributed Raman amplification uses the optical fiber itself as the gain medium through stimulated Raman scattering, eliminating the need for separate high-power amplifier devices. The pump lasers provide distributed amplification along the transmission fiber, reducing thermal management complexity and device size.
2Object-affected harmful factors
If high-output optical amplifiers are used to reduce noise at high bit rates, then noise reduction is improved, but power consumption increases
Solution Approach 1:
The total amplification gain is segmented across multiple distributed Raman amplification sections, allowing each pump laser to operate at lower power levels while achieving the same cumulative noise reduction effect as a single high-output amplifier would provide.
Solution Approach 2:
The invention changes the amplification mechanism from conventional erbium-doped fiber amplification to distributed Raman amplification, utilizing stimulated Raman scattering to provide distributed gain. This parameter change enables lower overall power consumption while maintaining noise performance through the distributed nature of the amplification.
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
This approach allows for stable transmission and reception of high-bit-rate signals without the need for high-output optical amplifiers, reducing power consumption and thermal issues, while maintaining signal quality by focusing on auto level control and single-wavelength amplification.
Implementation Method 1
The TOF 213 includes a collimator 213A for inputting multiplexed light, a diffraction grating 213B for separating wavelengths, a MEMS mirror 213C for reflecting light with a specific wavelength, and a collimator 213D for outputting light with the specific wavelength
Implementation Method 2
The TOF 213 transmits transmission light with a specific wavelength from the transmission light travelling from the optical amplifier 212 by adjusting a reflection angle of a MEMS mirror 213C
Implementation Method 3
The optical amplifier 212 optically amplifies the transmission light travelling from the modulator 211
Implementation Method 4
The modulator 211 optically modulates the data signal, which is the electric signal and which comes from the DSP 206, on the basis of the laser light travelling from the BS 203
Implementation Method 5
The PD 216 performs electric conversion on the part of transmission light that has been split by the transmission-side BS 215, and detects a level of the transmission light
Data Source
AI summary
A coherent transceiver includes a modulator, a receiver, a filter, a splitter, a detector, and a controller. The modulator modulates a data on the basis of laser light and outputs transmission light. The receiver receives reception light with same wavelength as the transmission light from input multiplexed light, on the basis of the laser light. The filter is arranged on an input stage of the receiver and includes a first port that inputs the multiplexed light, a filter body that transmits the reception light from the multiplexed light, and a second port that outputs the transmitted reception light. The splitter splits the transmission light travelling from the modulator and inputs the splitted transmission light. The detector detects a level of the splitted transmission light input. The controller adjusts a passband of the filter on the basis of the detected level.