研究目的
To analyze the impact of frequency chirp in directly modulated long-wavelength VCSELs for high-capacity optical metro networks, evaluating transmission performance with DMT modulation and WSS filtering.
研究成果
Directly modulated long-wavelength VCSELs can achieve over 50 Gb/s per polarization in metro networks with coherent detection, even after multiple WSS crossings and over hundreds of kilometers. Lower chirp VCSELs perform better for DSB modulation, while a limited amount of chirp can benefit SSB modulation at lower OSNRs. This approach offers a cost-effective and efficient solution for high-capacity optical communications.
研究不足
The study is limited to specific VCSEL designs and assumes ideal conditions in simulations. The tunable VCSEL with lower chirp is not currently available with high modulation bandwidth, and the impact of chirp may vary with different network configurations. Further optimization of chirp and filter bandwidth trade-offs is needed.
1：Experimental Design and Method Selection:
The study involves experimental measurements of chirp parameters for two types of InP VCSELs (short-cavity and tunable with MEMS top mirror) using a small-signal frequency response analysis. Simulations are conducted using a Matlab-based tool to model transmission performance with DMT modulation, coherent detection, and WSS filtering.
2：Sample Selection and Data Sources:
Two VCSEL devices are used: a 20-GHz short-cavity VCSEL and an 8-GHz tunable VCSEL. Data is collected from experimental setups and simulations.
3：List of Experimental Equipment and Materials:
Equipment includes a vector network analyzer, VCSELs, SSMF coils, EDFA preamplifier, PIN photodiode, VOA, temperature controller, and WSS with 25-GHz spacing.
4：Experimental Procedures and Operational Workflow:
For chirp measurement, VCSELs are directly modulated, and the signal propagates through SSMF of varying lengths. The transfer function is measured and fitted to extract chirp parameters. Simulations involve generating DMT signals, applying WSS filtering, propagating through SSMF with EDFAs, and using coherent detection with DSP for CD compensation and bit loading.
5：Data Analysis Methods:
Chirp parameters are estimated by fitting experimental data to theoretical models. Transmission capacities are evaluated using Chow's bit loading algorithm with a target BER of 3.8e-3, and performance is analyzed based on OSNR, number of WSS crossings, and fiber span length.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容-
Vector Network Analyzer
40-GHz bandwidth
Generates RF signal for small-signal modulation analysis of VCSELs.
-
VCSEL
20-GHz short-cavity
Optical source for direct modulation and transmission experiments.
-
VCSEL
8-GHz tunable with MEMS
Optical source with wide tunability for chirp measurement.
-
EDFA
Optical amplifier to compensate for transmission losses.
-
PIN Photodiode
25-GHz electrical bandwidth
Converts optical signal to electrical for detection.
-
VOA
Attenuates optical signal to maintain constant received power.
-
WSS
25-GHz spacing
Filters optical signals in WDM networks.
-
SSMF
Transmission medium for optical signals.
-
Temperature Controller
Maintains constant temperature for VCSEL operation.
-
登录查看剩余7件设备及参数对照表
查看全部
