Zhike Zhang

A 3D RF impedance matching circuit used to package of multi-channel parallel EML array

In this paper, a novel three-dimensional (3D) RF impedance matching circuit has been designed to match the characteristic impedance of RF transmission line and reduce the reflection of RF signal. It consists of a coplanar RF transmission line array circuit and a non-coplanar termination resistor array circuit. The latter is vertically installed on the RF transmission line array circuit by soldering. The resistor array is fabricated on the two sides of circuit board that helps to increase the heat dissipation and power density of resistor. Simultaneously, the thermal characteristic is greatly improved. Moreover, the structure overcomes the limitation of conventional microwave circuit design which only focuses on two-dimensional (2D) plane. In the design, electrical crosstalk between transmission lines is comprehensively investigated by building simulation model based on three-dimensional electromagnetic field simulator. Finally, as the measurement result demonstrates, the RF impedance matching circuit we fabricated, which is only 5mm×4mm×1.2mm in size, has a good performance with reflection response of less than -10dB at about 22GHz and the 3-dB transmission bandwidth has reached up to 20GHz. The circuit can be used to the compact package of multi-channel parallel electro-absorption modulator laser (EML) array, electronic absorption modulator (EAM) array and Mach-Zehnder modulator (MZM) array.

30-GHz directly modulation DFB laser with narrow linewidth

we report a 1.3μm 30-GHz directly modulation distributed feed-back laser with narrow linewidth of 130kHz and high side-mode suppression ratio of 52dB. The output power is more than 16mW at 100mA and the input 1-dB compression point is showed with different frequencies.

Packaging investigation of optoelectronic devices

Compared with microelectronic packaging, optoelectronic packaging as a new packaging type has been developed rapidly and it will play an essential role in optical communication.In this paper, we try to summarize the development history, research status, technology issues and future prospects, and hope to provide a meaningful reference.

Modulation properties enhancement in a monolithic integrated two-section DFB laser utilizing side-mode injection locking method

A monolithic optical injection-locked (MOIL) DFB laser with large stable injection locking range is experimentally demonstrated using the side-mode injection locking technique. The low-frequency roll-off in the MOIL DFB laser is suppressed significantly. The relaxation oscillation frequency is measured to be 26.84 GHz and the intrinsic 3-dB response bandwidth is more than 30 GHz, which is about 20 GHz higher than that of the free running DFB laser. The nonlinear distortions, including the 1-dB compression point, second harmonic distortion (2HD) and third-order intermodulation distortion (IMD3), are also suppressed significantly. A simple radio-over-fiber system transmitting 40 Msymbol/s 32-QAM signal with 6 GHz carrier is achieved using the MOIL DFB laser. After 50 km transmission, the average error vector magnitude (EVM) of the whole link is 2.94% in injection locked state, while the EVM in free running DFB laser is 5.25% as a comparison. To our knowledge, this is the first time that the MOIL DFB laser is realized utilizing the side-mode injection locking method.

Three-dimension package design for electro-absorption modulation laser array

We report a new 3-D package design technique in this paper. Based on this technique, a 3-D RF impedance matching circuit used in the packaging of electroabsorption modulation laser (EML) array is achieved, which has the characteristics of low electrical crosstalk and small size. The 3-D package design technique overcomes the limitation of conventional 2-D design technique in which many bonding wires have to be employed. The measurement results demonstrate that the 3-D impedance matching circuit has a transmission bandwidth of 25 GHz and the reflection is suppressed below -10 dB in a wide frequency range. Compared with NTTs schemes, the 3-D impedance matching circuit and the wires in our scheme have a lower electrical crosstalk. A ten-channel EML module is fabricated, employing the above technique, and demonstrated. The module has good frequency characteristics over a bandwidth of 10 GHz. To our knowledge, this is the first time that such a 3-D impedance matching circuit has been reported publicly.