Investigation of Semiconductor Lasers for Wideband Recording
Abstract
The purpose of this investigation was to determine if it is feasible to build a wideband laser recorder using a semiconductor laser as the film exposure source. The argon laser and its external light modulator of a Government furnished, developmental wideband FM recorder/readout system were replaced by an internally modulated laser diode. The lasers were developmental (Al Ga)As devices supplied by RCA Laboratories. These double-heterojunction lasers were capable of emitting continuous output powers up to 10 mW at 710 nm when operated at 77 K. The semiconductor lasers have been internally modulated from 1-200 MHz (+ or - 2 dB) and film recording frequencies in excess of 100 MHz (160 cycles/mm) have been made. Stationary film playback of a 30-MHz FM recording achieved a 31 dB (p-p to rms) wideband signal-to-noise ratio over a 30-MHz bandwidth. Tradeoffs for diode operation at elevated temperatures are discussed. Comparisons are made between semiconductor laser performance and data taken previously on the argon laser recorder.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1975
- Accession Number
- ADB004233
Entities
People
- J. E. Roddy