Optical devices using an external cavity semiconductor laser

In an optical system including a semiconductor diode laser having opposed first and second facets, a method for providing a source of modulated optical energy comprising the steps of:

• positioning an at least partially optically reflective surface a predetermined distance from one of said first and second facets, thereby forming a resonant cavity between said one facet and said at least partially optically reflective surface;
• and
• modulating said predetermined distance between said at least partially optically reflective surface and said one facet so as to modulate amplitude of optical output produced by said semiconductor diode laser.

In an optical system including a semiconductor diode laser having opposed front and rear facets, a method for providing a source of modulated optical energy during operation of said laser in a signal generation mode and for amplifying light input during operation of said laser in an amplification mode, said method comprising the steps of:

• applying said light input to said front facet during operation in said amplification mode;
• amplifying said light input within said laser during operation in said amplification mode;
• positioning an at least partially optically reflective surface a first predetermined distance from one of said front and rear facets during operation of said device in said amplification mode, and positioning said at least partially optically reflective surface a second predetermined distance from said one of said front and rear facets during operation in a signal generation mode so as to induce optical oscillation within said body of semiconductor material.