Kuniharu Kato

Low-loss laser diode module using a molded aspheric glass lens

The fabrication and characteristics of a 1.3- mu m laser diode (LD) module for single-mode fiber using a molded aspheric glass lens is discussed. An average coupling loss of 2.2 dB with a standard deviation of less than 0.5 dB after thermal heat cycling tests was achieved. The average assembly loss was 0.24 dB. The LD module demonstrated stability during thermal and heat cycling tests from -10 to 60 degrees C.<<ETX>>

Broad passband multi/demultiplexer for multimode fibers using a diffraction grating and retroreflectors

A broad passband multi/demultiplexer for multimode fibers employing a diffraction grating and retroreflectors is presented. As shown by calculation and experimental results, a passband width proportional to the difference between the retroreflector length and the input fiber core diameter is attainable. Using a standard ( 50/125 mu m) graded index fiber as the transmission fiber, 1-dB passband widths of 100 nm for the multiplexing channel and 94 nm for the demultiplexing channel with a channel spacing of 125 nm are achieved in a two-channel multi/demultiplexer. The minimum insertion losses for each channel are 2.3 and 2.7 dB, respectively.

Plastic module of laser diode and photodiode mounted on planar lightwave circuit for access network

Low-cost plastic packaging of laser diodes and photodiodes mounted on planar lightwave circuit (PLC) platform are developed and its reliability is confirmed under various environmental and endurance tests. The high performance of the module is maintained under reliability tests, such as high-humidity high-temperature tests (85/spl deg/C, 85%RH) and temperature cycling tests (-40/spl deg/C/85/spl deg/C). No laser diodes show any device characteristics change during environmental tests and their stability has very little dependence on current bias. Although the photodiodes show an increase in leakage current under high-temperature high-humidity tests and the rate of leakage current increase is proportional to the square root of bias voltage, the increase is negligible for system use. These plastic modules can be applied to actual access networks and other fiber-optic networks.

Optical coupling characteristics of laser diodes to thermally diffused expanded core fiber coupling using an aspheric lens

A discussion is presented of the optical coupling characteristics of a 1.3 mu m laser diode to a thermally diffused expanded core (TEC) single-mode fiber coupling using an aspheric lens. The misalignment tolerance width for a 0.5 dB loss increment of the expanded core fiber was enlarged to 8.4 mu m from 1.9 mu m of a nonexpanded core fiber without a remarkable coupling-loss increase. The TEC fibers will make the LD module assembly easier, and reduce the assembly cost.<<ETX>>

Three-channel WDM transceiver module assembled by adjustment-free process using aligned LED and PD ball-lens packages

A technique is proposed for assembling wavelength-division-multiplexing transceiver modules by an adjustment-free process using previously aligned LED and PD (photodiode) ball-lens packages. This technique utilizes a jig to position the module component accurately. The tolerance limits of the dimension and angle errors of the module components are specified by random-number simulation. According to simulation and experiments, the fabrication yield of a three-channel module using a multimode fiber is confirmed to be about 90% when the assembly loss increase is limited to 0.5 dB. >

Packaging technologies for large-scale integrated-optic planar lightwave circuits

Summary form only given. Packaging technologies are important in order to utilize planar lightwave circuits (PLCs) practically in indoor and outdoor environments. There is no clear guideline for categorizing large-scale integrated-optic PLCs. However, in this paper, a star coupler and an arrayed-waveguide grating (AWG) multiplexer with channel number more than 32, and a matrix optical switch with a scale more than 8/spl times/8, are categorized as large-scale PLCs because of their large channel-number or large number of switch elements. Developmental objectives and techniques for packaging large-scale integrated-optic PLCs are described.

Plastic Packaging Reliability of Optoelectronic Devices for Telecom Use

Two types of plastic modules for laser diodes and photodiodes are developed and tested under various environmental conditions. The stable operations for both types of modules are confirmed under various long-term aging tests, high humidity high temperature tests (85°C, 85% RH), and temperature cycling tests (-40 / +85°C). These plastic moduless are potentially suitable for economic access networks.