Yasushi Fujimura

Characterization and theoretical analysis of second-order intermodulation distortion of InGaAs/InP p-i-n photodiode modules for fiber-optic CATV

InGaAs/InP p-i-n photodiode (PD) modules for fiber-optic analog CATV have been developed. The optical configuration was optimized by making use of a spherical lens aberration. Responsivity and second-order intermodulation distortion (IMD2) were 0.95 A/W and -85 dBc at V/sub r/=12 V, P/sub in/=0 dBm, and m=40%, respectively. The improvement of IMD2 by defocusing was explained by the decrease of incident optical power density calculated by ray tracing. IMD2 was quantitatively explained through the reverse voltage dependence of responsivity which originates from the variation of the p/sup +/-InGaAs depletion layer thickness.

A coaxial-type 1.3/1.55 /spl mu/m WDM-PD module for optical access networks

A new 1.3/1.55 /spl mu/m WDM/photodiode(PD) module has been designed and fabricated for use in optical access networks. A 1.3 /spl mu/m-PD and a 1.55 /spl mu/m-PD were arranged in series along the optical axis in a coaxial package. The 1.3 /spl mu/m-PD with an In/sub 0.66/Ga/sub 0.34/As/sub 0.76/P/sub 0.24/ photosensitive layer (/spl lambda//sub g/=1.42 /spl mu/m) absorbs 1.3 /spl mu/m digital optical signals and it is transparent to 1.55 /spl mu/m wavelength. The 1.55 /spl mu/m-PD with an In/sub 0.53/Ga/sub 0.47/As photosensitive layer absorbs 1.55 /spl mu/m analog optical signals. Responsivity of the module is 0.82 A/W at 1.31 /spl mu/m wavelength and 0.75 A/W at 1.55 /spl mu/m wavelength, respectively. IMD2 of the 1.55 /spl mu/m-PD measured by two-tone method was -76.1 dBc at Pf(1.55 /spl mu/m) of -6 dBm. Bit error rate (BER) of the 1.3 /spl mu/m-PD was measured at 28.8 Mb/s by using an amplifier with bandwidth of 200 MHz and was found to be less than 10/sup -8/ at Pf(1.3 /spl mu/m) of -30 dBm.

A compact coaxial-type optical transceiver module using a half-transmittance photodiode for TCM optical access networks

A compact coaxial-type optical transceiver module has been developed without using a conventional 3 dB optical coupler. This transceiver is composed of a newly designed half-transmittance photodiode (HT-PD) and a 1.3-/spl mu/m-MQW-LD. An HT-PD is used both as a photodetector and as a window for LD light. Fiber output power of 1.15 mW at the drive current of 26 mA and responsivity of 0.48 A/W at the reverse-voltage of 5 V were obtained. Temperature dependence of responsivity is also reported.

Low power consumption molded gigabit fiberoptic transceiver module

The standardization task of gigabit Ethernet by IEEE802.3z working group is attracting a great deal of attention. The demands for the modules compliant with the standardized specification will be increased. We have successfully developed gigabit fiberoptic transceiver modules compliant with 1000BASE-LX, proposed specification in gigabit Ethernet. The main feature of this module is 3.3 V operation which leads to low power consumption, while most of the conventional modules operate at 5.0 V. We used the newly designed package with lower profile 9.4 mm in height. The carefully designed modules package was formed by transfer mold encapsulation techniques which contribute to the cost reduction. In this paper, the design, assembling process, and characteristics of the developed module are described.

High-responsivity L-band micro intradyne coherent receiver using InP-based photodetector integrated with 90-degree hybrid

We demonstrate a high responsivity of 64 GBaud micro intradyne coherent receivers (Micro-ICR) operating at the wavelength range from 1565 nm to 1612 nm (L-band). The package body size is 12.0 mm × 22.7 mm × 4.5 mm, which is fully compliant with OIF implementation agreement. A newly developed InP-based photonic integrated circuit (InPPIC) for the L-band High-Bandwidth Micro-ICR is composed of the high-speed p-i-n-photodiode array (f3dB > 40GHz) and a 90° hybrid waveguide consisting of MMIs which is designed to obtain high transmittance over the L-band. They are monolithically integrated through butt-joint regrowth in which a GaInAs absorption layer of the photodiode is directly connected with a GaInAsP core layer of the 90° hybrid in order to achieve the high responsivity with high optical coupling efficiency. Furthermore, the optical couplings between optical fibers and InP-PICs are realized by low optical loss micro optics. Receiver responsivities of more than 65 mA/W for signal input and local input are achieved within the L-band at 25°C. The wide 3-dB bandwidth of 40 GHz is also confirmed using high-bandwidth TIA. These values are comparable to the coherent receiver for 64 GBaud C-band applications. This receiver module is very promising for the increase of transmission capacity through expansion of operation wavelength (C-band and L-band).

Optical WDM transceiver module using wavelength-selective coupler and WDM-PD for optical access networks

We have proposed a new WDM-transceiver module using a wavelength-selective coupler and a 1.3 /spl mu/m InGaAs WDM p-i-n photodiode and InGaAsP MQW laser diode in order to reduce component number and module size. In this report, we confirmed the fundamental operation of this module assembled with pigtailed components. Evaluation results imply that this WDM transceiver module is promising for application to an optical WDM transceiver/receiver.

3.5-mm-square InGaAs p-i-n photodiodes and their application to optical-axis arrangement between 1.3-/spl mu/m laser diodes and a SMF

InGaAs p-i-n photodiodes (PD) with 3.5-mm/spl times/3.5-mm-large photosensitive area have been fabricated using chlorine-vapor-phase-epitaxial (C-VPE) growth. They showed high responsivity of 0.95 A/W (/spl lambda/=1.3 /spl mu/m) and 1.2 A/W (/spl lambda/=1.55 /spl mu/m) and good homogeneity in the whole area. Long-term reliability was confirmed through high-temperature aging tests at 150/spl deg/C up to 5200 hours. A PD with two pairs of parallel electrodes (PE-PD) was applied to optical-axis arrangement between 1.3-/spl mu/m laser diodes (LDs) and a single mode fibre (SMF). The beam position of a LD was detected in error within /spl plusmn/20 /spl mu/m using PE-PD prior to coupling of a LD beam into a SMF. Total inspection time was reduced to one third the original time.