Yoshitaka Yokoyama

1.55-μm wavelength-selectable microarray DFB-LD's with monolithically integrated MMI combiner, SOA, and EA-modulator

We developed compact (1.136 mm/sup 2/) eight-channel wavelength-selectable microarray distributed feedback laser diodes (DFB-LDs) with a monolithically integrated 8/spl times/1 multimode-interference (MMI) optical combiner, a semiconductor optical amplifier (SOA), and an electro-absorption (EA) modulator. By using /spl plusmn/10/spl deg/C thermal tuning, an addressable wavelength range of 15.3 nm with uniform device characteristics and 2.5-Gb/s modulation performance were successfully demonstrated.

Growth pressure dependence of neighboring mask interference in densely arrayed narrow-stripe selective MOVPE for integrated photonic devices

We have investigated the dependence of neighboring mask interference on growth pressure in narrow-stripe selective MOVPE with arrayed stripe masks for the growth of densely-arrayed optical waveguides. Atmospheric-pressure MOVPE is effective in fabricating densely arrayed waveguide without inducing neighboring mask interference. On the other hand, low-pressure MOVPE has the advantage that the distribution of PL-wavelength over the microarray waveguide can easily be controlled by utilizing neighboring mask interference. An appropriate mask pattern and growth conditions for fabricating integrated photonic devices can thus be selected. A mask interference constant was introduced and used to simulate distributions of PL-wavelengths in arrayed waveguide. Simulated results matched experimental results well.

Multiwavelength locker integrated wide-band wavelength-selectable light source module

A wide-band wavelength-selectable light source module having an integrated multiwavelength locker has been developed. An eight-distributed-feedback (DFB) arrayed monolithic light source was designed to have 40-nm tunable range in the L-band by covering 5 nm per DFB laser diode. A uniquely designed etalon-based wavelength locker achieved very stable operation and uniform locking performance for all channels. Wavelength variation in the short term at room temperature was much less than 1 pm and the locked wavelength stayed within +/-5 pm when the case temperature of the module was varied from -20/spl deg/C to 65/spl deg/C.

1.55 /spl mu/m wavelength-selectable microarray DFB-LDs with integrated MMI combiner, SOA, and EA-modulator

We developed compact (1.136 mm/sup 2/) eight-channel wavelength selectable microarray DFB-LDs with monolithically integrated 8/spl times/1 MMI combiner, S0A, and EA-modulator. The wavelength tuning range of 15.3 nm with uniform device characteristics and 2.5 Gbit/s modulation performance were successfully demonstrated.

94-channel wavelength-selectable light source module with integrated multiwavelength locker

We have first reported on a 94-channel wide-band WSL installed in a 22-pin butterfly package with a multi-wavelength locker. We could realize 40-nm operation in the L-band for an 8-DFB arrayed monolithic WSL by covering 5 nm per DF3-LD. By using a monolithically integrated WSL and minimizing the number of components on the wavelength locker we could install all function in a 12.7-mm /spl times/ 20.8-mm standard butterfly package. This WSL module with a stable-wavelength operation and uniform locking performance is a promising development to provide a large degree of flexibility in DWDM system design.

Wavelength-independent operation of EA-modulator integrated wavelengthselectable microarray light sources

In this letter, we have simultaneously fabricated five wavelength-selectable microarray light sources (WSLs), each having a different wavelength range integrated with an electroabsorption (EA) modulator on a single wafer. We also introduced a novel device configuration scheme for wavelength-independent modulation. The five EA-WSLs fully covered the entire C-band and had a low uniform threshold current of 6 /spl plusmn/ 1 mA at 25/spl deg/C. Wavelength-independent extinction characteristics were obtained over a tuning wavelength range of 8 nm, and 2.5-Gb/s transmission over 600 km was successfully achieved.