Coaxially mounted high frequency light detector housing

In a light detector housing which comprises:

• a header having two openings therethrough;
• an electrical bias lead and an electrical signal lead, each extending through said header, wherein said bias lead and said signal lead are fastened to and electrically isolated from said header;
• a light detector having two terminals and a light sensitive surface mounted on said signal lead and having a first terminal electrically connected to said signal lead;
• means for electrically connecting a second terminal of said light detector to said bias lead;
• an electrically conducting cap fastened to and electrically connected to the header so as to enclose said bias lead, said electrical signal lead and said light detector;
• a light transmissive medium mounted in said cap, whereby light impinging on said light transmissive medium enters the housing and impinges on the light sensitive surface of said light detector mounted on and;
• the improvement which comprises:
• an electrical signal lead which comprises a coaxial transmission line, having a central conductor, wherein a first terminal of said light detector is electrically connected to the central conductor;
• and
• an electrically conducting sheet, electrically connected to said bias lead and extending at least partially around said light detector;
• means for supporting said electrically conducting sheet;
• one or a plurality of capacitors each having a first plate electrically connected to the header and a second plate electrically connected to said electrically conducting sheet wherein said capacitors are of an effective capacitance to provide a low impedance electrical connection between the electrically conducting sheet and the header at radio frequencies and a high impedance at zero frequency.