高饱和电流光电探测器在低噪声系数和高增益RoF光链路中的应用

Applications of high-saturation-current photodiode in the RoF links with low noise figure and high gain

研究了光载无线通信(RoF)链路中掺Er3+光纤放大器(EDFA)对链路噪声系数(NF)和增益的影响,同时采用自制的具有高响应度、高饱和功率特性单载子传输光电探测器(UTC-PD)作为链路光电转换器件,在不以NF为代价的同时使得链路增益性能获得大幅提升。实验表明,对于由LD、马赫-曾德调制器(MZM)、EDFA、光滤波器(OBPF)和UTC-PD组成的RoF光链路,在LD输出功率为17dBm、UTC-PD的输出平均光电流为60mA时得到最低链路NF为30.3dB,相比不含EDFA的基本链路在LD输出光功率同为17dBm时的NF略小0.4dB;同时链路增益高达15.5dB,相比基本链路大幅提升了41.3dB。

In this paper, the effects of utilizing an Er3＋ doped fiber amplifier （EDFA） in analog optical links on the link characteristics, i. e. , noise figure and gain, are invesitgated, while a high-responsivity and high saturation-power uni traveling-carrier photodiode （UTC-PD） developed by ourselves is adopted as the optoelectronic conversion component to sustain high power operation. A great enhancement in the link gain is expected,without sacrificing the noise figure performance. The experiment is carried out to compare the performance of two links,one of which is composed of a laser diode （LD） ,a Mach-Zehnder modulator （MZM） and a photodiode （PD） ,while the other of which is composed of an LD,a MZM,an EDFA, an optical band pass filter （OBPF） and a PD. The link performance is characterized based on the Y factor method. When the LD output power is set to 17 dBm and the DC photocurrent of the PD is as high as 60 rnA by utilizing an appropriate pump for the EDFA,the later link has demonstrated the lowest noise figure of 30. 3 dB, which is 0.4 dB smaller than that of the former one without an EDFA. Meanwhile,the gain of the later link is as high as 15.5 dB,which is 41.3 dB larger than that of the for mer one.