Takashi Motoda

Uniform Fabrication of Highly Reliable, 50-60 mW-Class, 685 nm, Window-Mirror Lasers for Optical Data Storage

Uniform fabrication of highly reliable 50–60 mW-class 685 nm laser diodes (LDs) with a window-mirror structure has been realized by using selective solid-phase Zn diffusion and three-inch full wafer processing. A window-mirror structure at the LD mirror is formed by Zn-induced disordering of an ordered GaInP multiple quantum-well (MQW) active layer. High uniformity of characteristics such as the operating current and the far-field pattern has been obtained by realization of highly uniform Zn diffusion. A small astigmatic distance (ΔZ3 µ m), a low relative intensity noise (RIN-135 dB/Hz) and a high speed response (T r, T f1.2 ns) are obtained in addition to the high-power and high-temperature characteristics (70 mW, 80° C) in spite of the existence of the window structure. The LDs have exhibited reliable 6,000–10,000 h operation under the conditions of 60° C and 50–60 mW for the first time.

Reliability study on 50-100-mW CW operation of 680-nm visible laser diodes with a window-mirror structure

We have studied reliability of 680-nm visible laser diodes (LDs) with a window-mirror structure formed by zinc-diffusion-induced disordering of GaInP quantum wells. Aging tests under the condition of CW output power in the range of 50-100 mW for ambient temperature from 40/spl deg/C to 70/spl deg/C have been carried out for 650-/spl mu/m-long LDs and 900-/spl mu/m-long LDs with three kinds of the front facet reflectivities (1.5%, 6% and 13%). In all tests, laser operation was stable for over 5000 h. For example, reliable 500-10000-h operation of the 900-/spl mu/m LDs was realized under the conditions of output power of 50 mW at 70/spl deg/C, 70 mW at 60/spl deg/C, and 100 mW at 40/spl deg/C for the first time. By various aging test results, dependence of the temperature and the output power on increase of the operating current has been investigated. Also, influences of the facet reflectivities and the cavity lengths on the reliability have been studied with focus on the optical power density and the current density. Consequently, it has been clarified that the degradation of the window LDs rather strongly depends on the operating current density than the optical power density. Moreover, it has been proven that the reliability of the window LDs is effectively improved by the reduction of the operating current density due to extension of the cavity length.

Uniform and high-power characteristics of AlGaInP visible laser diodes and their four-element arrays fabricated on a three-inch /spl phi/ wafer

The versatile potential of a three-inch diameter wafer processing technology has been successfully demonstrated by the realization of a large number of 680 mn high-power laser diodes (LDs) and their individually addressable four-element arrays on a single wafer at one time. The excellent uniformities of the laser characteristics, such as threshold current, operating current, beam divergences and lasing wavelength have been obtained. The LDs have been operating stably for over 2500 hours under the condition of 60/spl deg/C and 30 mW. In the four-element LD arrays with a junction-up configuration, the linear power-current (P-I) characteristics have been obtained up to 50 mW, even at 50/spl deg/C for each element. Moreover, the thermal crosstalk, defined as the output decrease rate caused by the temperature rise due to neighboring elements operation of 2.9-11.1%, has been realized in the high-power simultaneous operation. >

Reliability of 680-nm window laser diodes at 50-100 mW CW operation

By reduction of the operating current density due to a long cavity length of 900 /spl mu/m, reliable 5,000-hour operation of 680-nm window lasers has been realized under the conditions of 70 mW at 60/spl deg/C and 100 mW at 40/spl deg/C for the first time.

Highly reliable 685-nm 50-mW visible lasers with Zn-diffused windows

High-power, highly reliable 685 nm Zn-diffused type window structure laser diodes (LDs) are developed using 3-inch (phi) wafers. The lasers have exhibited over 7000 hours operation under the condition of 60 degrees Celsius, 50 mW. In addition, over 4000 hours operation under the condition of 60 degrees Celsius, 60 mW is also achieved. These LDs are fabricated by well controlled 3-inch full wafer processing. The window regions near both facets consist of the disordered GaInP wells formed by an open-tube solid-phase Zn-diffusion technique. It is confirmed that highly uniform characteristics are achieved over the 3-inch wafer. Moreover, low astigmatic distances of less than 3 micrometer m are obtained in the range of 3 - 50 mW in spite of the window structure.

Uniform and high-power characteristics of AlGaInP visible laser diodes and their four-element arrays fabricated on a 3-inch wafer

Summary form only given. High-power, 68O nm laser diodes (LDs) with uniform characteristics and 100 /spl mu/m-spaced, 4 element individually addressable LD arrays have been fabricated, for the first time, on a 3-inch GaAs substrate. The LDs have been operating for over 2,000 hours and the elements of the LD arrays have exhibited uniform high-power and high-temperature characteristics.