The transmission loss in quartz optical fibers has been reduced by the reduction of hydroxyl (OH) groups so that the minimum loss is presently located at around 1.3 /xm and 1.55 /xm. Because of these properties of quartz optical fibers, fiber communications are realized in these wavelength regions. For quaternary InGaAsP III-V alloys in these wavelength regions, InP is an indispensable material since it has a good lattice matching with these alloys. InP is therefore a key material for the production of InP photonic devices such as laser diodes (LDs), light emitting diodes (LEDs) and photodetectors in these communications . In reality, high-speed Internet communication systems are now established wholeover the world based on these devices.